Introduction

This document summarises the Round 1 - Initial estimates of the ACT Urban Habitat and Connectivity Project expert elicitation for small woodland birds using the IDEA protocol (refer to Hemming et al. 2018 “A practical guide to structured expert elicitation using the IDEA protocol” and Burgman 2016 “Trusting Judgements: How to get the best out of experts”).

For each question asked in the expert elicitation, we have summarised the results. All responses from the expert elicitation remain anonymous, with visualised experts estimates being denoted by a number on the x- axis. Below each visualised estimate, the comments provided by experts are collated.

The intervals displayed are for a Three-Step Elicitation.

Shared resources

Please click the link provided to access the PDFs and documents provided by experts in the initial estimates round

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Structural habitat metrics

The next series of visualisations relate to structural habitat metrics.

Structural habitat metrics describe how the various elements of a species’ habitat are arranged in space. For example, some arboreal species may need tree canopies a certain distance apart to be able to successfully navigate from one to the next. Another species might require grass heights of a certain amount to escape predation, whilst another species might only be able to persist within a certain distance from a water body.

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Preferred distance between tree canopies

This could be related to the amount of shade the taxon group prefers or is tolerant of in its preferred habitat, the distance an arboreal species can move from one tree to the next without going along the ground, or some other feature of the taxon groups’ general biology or life history. This metric considers the availability of both exotic and native tree species in the environment, as well as both young and mature trees (> 3m height). The answer to this question will give an equivalent score to something like “percentage canopy cover”, which might be a more familiar (but harder to map) version of this metric.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 30 5.0 100 Not clear if birds use this cue, as opposed to tall trees–probably far more important for reptiles, given the effects on insolation and, hence, basking resources. My thinking here is guided by published research on foraging ecology and dietary composition of declining woodland birds, noting that 25 of the 26 species are insectivores, with most foraging primarily on detritovores in litter. So more trees = more litter, but too many trees = dark forest which they avoid, so my numbers are an attempt to find this Goldilocks zone 40 Small_woodland_birds tree_canopy Initial
51 100 0.0 200 Not confident on these distances at all. Some decent work done by Veronica Doerr et al. and Joern Fischer et al. but hard to say for small birds. Movement surveys rarely done at night, and not uncommon to find small birds colonising very isolated woodland patches. I suspect their dispersal ability is greater than we typically think. 10 Small_woodland_birds tree_canopy Initial
53 1 0.0 5

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the estimated canopy tree cover (%). My best, lower and upper estimates were derived from the raw data I recorded across the 158 sites where small woodland birds were present. 		60 Small_woodland_birds tree_canopy Initial
54 15 1.0 70 Based on observations of bird movement. Will vary between sepcies in this taxa. 80 Small_woodland_birds tree_canopy Initial
55 100 50.0 300 A guestimate. Birds as a group are highly mobile, eg upper estimate could be much higher, particularly for strong fliers, migratory species. 60 Small_woodland_birds tree_canopy Initial
56 15 2.0 70 I think canopy-foraging species like White-plumed Honeyeaters would struggle if they had to fly more than about 70 m from one tree to the next OVER AND OVER. Conversely, ground feeders like Yellow-rumped Thornbills, will be “shaded out” with canopies closer than 2 m apart. 50 Small_woodland_birds tree_canopy Initial
59 80 0.0 200 Here, I was thinking about the gap crossing patterns in the most sensitive woodland birds, particularly robins, wrens, treecreepers. Larger distances would be ok for honeyeaters and some thornbills, pardolotes, etc. Example paper attached, several more are published by this research group. 80 Small_woodland_birds tree_canopy Initial
60 20 0.0 200 Lowest estimate written as 0m - in that canopies could be touching. In reality, many woodland birds will even be fine with overlap of tree canopies (ie negative 2 or more) 75 Small_woodland_birds tree_canopy Initial
Aggregated 45 7.2 143 NA 57 Small_woodland_birds tree_canopy Aggregated

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Percentage of trees which need to be native

This relates to the composition of the urban forest or remnant woodland in terms of native and exotic trees. What percentage of trees need to be native for an area to be suitable habitat for this species group? This will relate to things such as food availability or the year-round availability of canopy cover. For some species, only native trees will be beneficial whilst other species might happily utilise any tree species as part of core habitat structure.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 80 25 100 This has never been quantified before, so is a seat of the pants guess. Some exotics need not be problematic, but if they dominate, I suspect that their litter fall (in terms of quantity, quality, associated allelochemicals and periodicity especially for deciduous taxa) will provide such a foreign resource base for the detritivores the ground-foraging birds rely on for food. Likewise, if eucalypts, acacias, ballasts, sallitrcis and casuarinas aren’t canopy dominates, foliage gleaners will simply forage elsewhere. This is crying out for dedicated research in peri urban habitats, gardens and parklands in the ACT, because this has never been quantified 15 Small_woodland_birds native_trees Initial
51 70 20 100 I’ve gone with a wide range to balance benefits to small bird diversity (req high % native) vs abundance (achievable at low % native). 50 Small_woodland_birds native_trees Initial
53 70 60 80

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the proportion of native vs. exotic canopy tree cover. My best estimate was derived from the mean proportion of native canopy tree cover across the 158 sites where small woodland birds were present. The upper and lower estimates came from the upper and lowest 95% confidence intervals, rounded to the nearest 10%. 		90 Small_woodland_birds native_trees Initial
54 80 0 100 Own observations and work by Karen Ikin where any tree good, but natives best. 70 Small_woodland_birds native_trees Initial
55 70 40 80 A guesstimate. Non-native structure is utilised by most birds at different times and for different periods of time (food, cover, movement corridor). Breeding for most woodland species (eg woodland-dependent group) relies on high % of native trees/veg. 70 Small_woodland_birds native_trees Initial
56 100 75 100 Some of the species (e.g. Yellow-rumped Thornbill) can cope with very low percentages of native trees, but the COMMUNITY as a whole is most abundant in native woodland. 75 Small_woodland_birds native_trees Initial
59 60 50 100 For many small birds, the origin of trees might be less important than levels of cover, and as long as some native nectar and insect sources are available, this might be ok, but my knowledge in this area is limited. 60 Small_woodland_birds native_trees Initial
60 25 0 100 Assumption that “non native” trees include planted trees which are of the same genus, but not a local species. Such as Tasmanian Blue Gums planted in the ACT. 33 Small_woodland_birds native_trees Initial
Aggregated 69 34 95 NA 58 Small_woodland_birds native_trees Aggregated

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Preferred distance between mature trees

This relates to the composition of the urban forest or remnant woodland in terms of native and exotic trees. What percentage of trees need to be native for an area to be suitable habitat for this species group? This will relate to things such as food availability or the year-round availability of canopy cover. For some species, only native trees will be beneficial whilst other species might happily utilise any tree species as part of core habitat structure.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 60 15 90 My thinking here is guided by tree height in these woodlands, using 30 m as the maximum height of a White Box or Blakely’s Redgum. Trees closer to one another than half canopy height are approaching forest densities, lacking the understory structure, space and warmth needed to fuel decomposition and abundant insect prey. Further than three canopy heights from another is beyond the crossing distance threshold as estimated by Doerr and Doerr. So, two trees apart = open woodland, strikes me as about the right neighbourhood. 60 Small_woodland_birds mature_trees Initial
51 500 0 1000 Really don’t know. I think mature trees are a motivation to move rather than a permeable feature. 10 Small_woodland_birds mature_trees Initial
53 20 10 40

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the direct count of remnant native trees in a 40m radius of each site. I interpreted the term ‘mature’ to mean remnant in this context. My best, lower and upper estimates were derived from the raw data I recorded across the 158 sites where small woodland birds were present. 		50 Small_woodland_birds mature_trees Initial
54 20 10 70 Based on observations in urban settings. 85 Small_woodland_birds mature_trees Initial
55 100 50 300 A guestimate. Same answer as for tree canopies distance? Not sure if there is significant difference between these two? 60 Small_woodland_birds mature_trees Initial
56 25 2 200 Mature trees are most likely to be important for Scarlet Robin (indirectly, by providing fallen branches) and Mistletoebird (by hosting Mistletoe). Distances (I have assumed between trunks, rather than canopies) are a guess. 25 Small_woodland_birds mature_trees Initial
59 80 0 200 similar to the first question, literature and personal observations suggest the most sensitive species have thresholds of dispersal ability (<200m), and mean distances avg around 80m during typical foraging movements. 80 Small_woodland_birds mature_trees Initial
60 25 0 200 Have entered the same estimates as for first metric as feel that for woodland birds, canopy trees implies the same thing as mature trees (and also assuming that this doesn’t mean ‘large old trees’ explicitly) 75 Small_woodland_birds mature_trees Initial
Aggregated 104 11 262 NA 56 Small_woodland_birds mature_trees Aggregated

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Preferred distance between mid-storey canopies

This metric might reflect the overall amount of mid-storey cover (0.5 – 3m height) required by a taxon group, or how far they can move between shrubs. This metric considers the availability of both exotic and native mid-storey species in the environment. The answer to this question will give an equivalent score to something like “percentage mid-storey canopy cover”, which might be a more familiar (but harder to map) version of this metric.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 50 5.0 250 Aside from regenerating canopy trees, mid storey plants are important structural elements of box gum grassy woodlands as far as birds are concerns. Some of the more forest-leaning taxa like Yellow Robins prefer more densely wooded galleys including wattles growing as understory shrubs, but as High Ford and other have reminded us, these are effectively forest birds that also live in denser parts of some woodlands. I’ve worked in woodlands with effectively no understory shrubs that supported the full complement of woodland birds. Canopy and ground layer FAR more important ion my view 55 Small_woodland_birds mid_canopy Initial
51 100 0.0 200 See previous comments re movement 10 Small_woodland_birds mid_canopy Initial
53 1 0.0 3

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the estimated mid-storey/shrub cover (%). My best, lower and upper estimates were derived from the raw data I recorded across the 158 sites where small woodland birds were present. 		70 Small_woodland_birds mid_canopy Initial
54 25 15.0 100 Dont think required for many, but crucil for some (i..e brown thornbill, speckled warblers) 70 Small_woodland_birds mid_canopy Initial
55 50 30.0 100 A guestimate 60 Small_woodland_birds mid_canopy Initial
56 15 1.0 40 Tricky, because some of the species (e.g. White-browed Scrubwren) like dense mid storeys, and others (e.g. Yellow-rumped Thornbill) don’t. Ideally, for this community you’d want small patches of habitat with dense midstorey, and larger patches with sparse or no midstorey, rather than a midstorey shrub every 15 m. I’d suggest that midstorey patchiness is important. 25 Small_woodland_birds mid_canopy Initial
59 50 0.0 100 small woodland birds reliant on understory vegetation would be predicted to have a lower typical gap-crossing preference to tree-dependent species. 60 Small_woodland_birds mid_canopy Initial
60 7 0.0 200 Entry iof 0 for lower estimate - when in reality, canopies of midstory plants could be overlapping and woodland birds would utilise them (which would be a negative estimate) 75 Small_woodland_birds mid_canopy Initial
Aggregated 37 6.4 124 NA 53 Small_woodland_birds mid_canopy Aggregated

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Percentage of native mid-storey vegetation

This metric might reflect the overall amount of mid-storey cover (0.5 – 3m height) required by a taxon group, or how far they can move between shrubs. This metric considers the availability of both exotic and native mid-storey species in the environment. The answer to this question will give an equivalent score to something like “percentage mid-storey canopy cover”, which might be a more familiar (but harder to map) version of this metric.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 70 0 100 Again, no data has been collected on this, so guesswork on my part. Given that canopy structure is all important for mid storey rather than provision of hollows, I think % native is a lesser concern that overall density. 40 Small_woodland_birds native_mid Initial
51 80 0 100 As per overstorey - diversity served by high native component - abundance can be achieved with low %. I’d be checking out the work of Rebecca Montague-Drake , Donna Belder and various Lindenmayer for small woody bird habitat stuff in this region. 50 Small_woodland_birds native_mid Initial
53 50 40 60

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the proportion of native vs. exotic mid-storey/shrub cover. My best estimate was derived from the mean proportion of native mid-storey/shrub cover across the 158 sites where small woodland birds were present. The upper and lower estimates came from the upper and lowest 95% confidence intervals, rounded to the nearest 10%. 		80 Small_woodland_birds native_mid Initial
54 80 0 100 Some exotics arguably more important than natives (blackberry, box thorn). Hard to know if 100% native best. 80 Small_woodland_birds native_mid Initial
55 50 30 80 A guestimate 60 Small_woodland_birds native_mid Initial
56 90 0 100 Given that the community evolved with a purely native midstorey, it probably does well with 100% native midstorey cover (assuming the full complement of original plant species is present). But I reckon in many cases the full complement of original plants won’t be present, and a bit of Blackberry or other exotic shrub probably improves the habitat value for these birds. 50 Small_woodland_birds native_mid Initial
59 75 50 100 less vulnerable small woodland birds are often found in areas dominated by by lantana, for example, but we do observe much higher bird diversity in areas with a high proportion of native vegetation, as this is more likely to provide seed, fruit and insects, not just structural cover. 70 Small_woodland_birds native_mid Initial
60 0 0 25 For many species, there is no need for native midstory species to be present. Many small woodland birds will happily exclusively use exotic midstory species as habitat 75 Small_woodland_birds native_mid Initial
Aggregated 62 15 83 NA 63 Small_woodland_birds native_mid Aggregated

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Preferred distance from ground layer vegetation

This metric enables mapping of the potential distribution for those species which are tied in some way to ground layer vegetation. This might be a small species which lives within the grass layer (e.g. invertebrates, reptiles) or a larger species which relies on grass as food (e.g. kangaroos). How far will this taxon group be found from ground-layer vegetation?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 12 0.00 30 Not sure I understand the question here, but I figure a treecreeper on the ground is zero, and flying to the top of a 30 m tall dead tree is 30 metres from the ground layer. 20 Small_woodland_birds ground_layer Initial
51 0 0.00 0 No answer here. Too uncertain and heterogeneity likely to trump distance. Ground layer critical for food/nesting resources, but doubt it plays a strong role in facilitating or blocking dispersal without some major caveats. 0 Small_woodland_birds ground_layer Initial
53 5 2.00 6

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the estimated grass cover (%) and referred to my catalogue of site photos. To be honest, I found this metric challenging as not all small woodland birds will be dependent on ground-layer vegetation. 		30 Small_woodland_birds ground_layer Initial
54 5 0.00 50 Really depends on presence of trees and shrubs. 70 Small_woodland_birds ground_layer Initial
55 0 0.00 0 Not important for birds 0 Small_woodland_birds ground_layer Initial
56 0 0.00 15 Does ground layer vegetation include veg in gardens and parks? I have assumed that it is everything except concrete. Only canopy birds will move far from ground layer veg - ground-feeding species like Scrubwrens, Thornbills, Fairywrens and Finches won’t. 75 Small_woodland_birds ground_layer Initial
59 0 0.00 0 while ground cover might be important to finches (grass seed resources), this metric is less likely to be important to most small passerines compared to tree and shrub cover 60 Small_woodland_birds ground_layer Initial
60 10 0.00 100 Assuming that ground layer vegetation means native or non native - and is opposed to bare ground, litter, or rock areas with no vegetation at all. 50 Small_woodland_birds ground_layer Initial
Aggregated 4 0.25 25 NA 38 Small_woodland_birds ground_layer Aggregated

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Percentage of native ground layer vegetation

This metric relates to the composition of the ground storey vegetation (grasses, rushes, forbs, sedges; < 0.5m height). What is the percentage of the ground layer vegetation which needs to be native to provide suitable habitat for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 75 40 100 This really matters in terms of providing the resources needed by small woodlands birds throughout the year, with this otherwise lovely sites dominated by exotic annuals simply not providing the right kinds of food and, possibly nesting materials and perching structures / opportunities to see and capture prey. Some exceptions (eg some of the seed eaters will favour exotic grasses), but those sites dominated by native ground covers will have more intact microbial communities and nutrient levels, so far better able to sustain bird communities though periodic droughts 40 Small_woodland_birds native_ground Initial
51 80 20 100 See other native composition comments. I think ground layer % native can be a strong indicator for high quality woodland and therefore a strong metric for diverse woodland bird communities (but not necessarily abundant ones). 50 Small_woodland_birds native_ground Initial
53 30 20 40

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the estimated grass cover (%) and referred to my catalogue of site photos. To be honest, I found this metric challenging as not all small woodland birds will be dependent on ground-layer vegetation. 		30 Small_woodland_birds native_ground Initial
54 100 0 100 Arguably more native better but for most species probably does not matter. 80 Small_woodland_birds native_ground Initial
55 50 30 80 A guestimate. Not based on studies. Woodland birds tolerance for non-native ground layer can be quite high, provided other native veg structures remain, eg mature eucalypts, range of smaller trees/wattles. 60 Small_woodland_birds native_ground Initial
56 90 0 100 I don’t think nativeness of ground layer veg is very important for this community, but as per a previous answer, the comm. has evolved with native ground storey veg so it probably doesn’t do the birds any harm! 25 Small_woodland_birds native_ground Initial
59 0 0 0 as suggested previously, this metric is not likely to be important to small songbirds 60 Small_woodland_birds native_ground Initial
60 50 0 100 Woodland birds can be sustained in areas of wholely non-native ground vege. 50 Small_woodland_birds native_ground Initial
Aggregated 59 14 78 NA 49 Small_woodland_birds native_ground Aggregated

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Minimum height of ground layer vegetation

This metric relates to the average height (excluding seed stalks or other reproductive structures) of grasses, sedges, rushes, forbs and other ground layer vegetation. It might affect things like the availability of food sources (e.g. grass seeds) or opportunities for small animals to escape from predators. What is the minimum height of ground layer vegetation that provides suitable habitat for this taxon group?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 30 10.0 130 Again, not sure of the relevance here, but I see this has a proxy measure of weediness or gazing pressure and have answered accordingly 25 Small_woodland_birds min_height_ground Initial
51 10 5.0 20 I could read into this, but no time right now (sorry!) I would think Brett Howland’s PhD thesis would be a good source for info on this. Otherwise, I’d sail close to standards for high quality BGW. 10 Small_woodland_birds min_height_ground Initial
53 10 0.0 10

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I referred to my catalogue of site photos to look at the average height of ground-layer vegetation, where present. To be honest, I found this metric challenging as not all small woodland birds will be dependent on ground-layer vegetation. 		40 Small_woodland_birds min_height_ground Initial
54 5 2.0 8

Most small birds are pounces so shorter vegetation best.

Howland, B.W., Stojanovic, D., Gordon, I.J., Radford, J., Manning, A.D. and Lindenmayer, D.B., 2016. Birds of a feather flock together: Using trait-groups to understand the effect of macropod grazing on birds in grassy habitats. Biological Conservation, 194, pp.89-99

Martin, T.G. and Possingham, H.P., 2005. Predicting the impact of livestock grazing on birds using foraging height data. Journal of Applied Ecology, 42(2), pp.400-408. 		90 Small_woodland_birds min_height_ground Initial
55 15 10.0 50 Guestimate. Refer next answer, p14. I think factors such as ground layer height variability and patchiness are more relevant. 60 Small_woodland_birds min_height_ground Initial
56 5 1.0 10 None. 25 Small_woodland_birds min_height_ground Initial
59 0 0.0 0 not likely to improve resources (diet or structure) important to small songbirds 60 Small_woodland_birds min_height_ground Initial
60 12 0.0 40 Assuming that this includes both native and non native vegetation 50 Small_woodland_birds min_height_ground Initial
Aggregated 11 3.5 34 NA 45 Small_woodland_birds min_height_ground Aggregated

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Maximum height of ground layer vegetation

As above, but this time please describe the maximum height of ground layer vegetation that provides suitable habitat for this taxon group? It might affect things like the ability of a species to effectively move through ground layer vegetation, or find suitable burrowing sites, or access to solar radiation.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 80 15 220 Some exotic grasses are well over my head when seeding in a good year–fine places to find Brown Quail and Rufous Songlarks, but otherwise, not quality bird habitat. More open is better, lower is better 30 Small_woodland_birds max_height_ground Initial
51 30 30 60 See prev comment 10 Small_woodland_birds max_height_ground Initial
53 30 20 50

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I referred to my catalogue of site photos to look at the average height of ground-layer vegetation, where present. To be honest, I found this metric challenging as not all small woodland birds will be dependent on ground-layer vegetation. 		40 Small_woodland_birds max_height_ground Initial
54 8 7 10

Most small birds are pounces so shorter vegetation best.

Howland, B.W., Stojanovic, D., Gordon, I.J., Radford, J., Manning, A.D. and Lindenmayer, D.B., 2016. Birds of a feather flock together: Using trait-groups to understand the effect of macropod grazing on birds in grassy habitats. Biological Conservation, 194, pp.89-99

Martin, T.G. and Possingham, H.P., 2005. Predicting the impact of livestock grazing on birds using fo 		90 Small_woodland_birds max_height_ground Initial
55 0 0 0 Not sure how to answer this. I think factors such as ground layer height variability and patchiness are more relevant. A uniform tall ground/grass layer in an area will limit use by woodland species. 0 Small_woodland_birds max_height_ground Initial
56 40 20 100 Really high grass would probably exclude Yellow-rumped Thornbills, but Finches and Fairy-wrens like to have some high grass. 25 Small_woodland_birds max_height_ground Initial
59 0 0 0 not likely to improve resources (diet or structure) important to small songbirds 60 Small_woodland_birds max_height_ground Initial
60 20 10 60 Assuming for native and non native vege 50 Small_woodland_birds max_height_ground Initial
Aggregated 26 13 62 NA 38 Small_woodland_birds max_height_ground Aggregated

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Non-structural habitat metrics

The next series of visualisations relate to non-structural habitat metrics.

This section asks questions regarding the non-structural elements which dictate habitat suitability for each taxon group. These includes things such as the amount of light which is tolerable at the time the species is active, or appropriate thermal conditions.

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Maximum tolerable night-time light levels

This metric relates to the maximum tolerable light level which is associated with suitable habitat for this taxon group. It relates to the amount of artificial light provided at night in the urban environment (e.g from streetlights, or buildings). For some species, artificial light may disrupt foraging behaviours, mate finding behaviours, or circadian rhythm.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 0.0 0.0 0 No data on this exists, save for some recent work on night-time singing of Willy Wagtail and Magpies. Given the large numbers of small woodland birds found in parklands and reserves were there are lights on all night for human safety, I think this is a lesser concerns for this group, but that’s purely a hunch. 0 Small_woodland_birds night_light Initial
51 0.0 0.0 0 Prob important, but I have no idea. 0 Small_woodland_birds night_light Initial
53 20.0 10.0 50

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I referred to my catalogue of site photos and my count of houses per site to estimate the amount of light that would be present at night. I also searched for some additional reference points in lux units (e.g. family room lights ~ 50 lux). 		40 Small_woodland_birds night_light Initial
54 10.0 5.0 15 No idea 10 Small_woodland_birds night_light Initial
55 0.0 0.0 0 I have no experience in this field to make any estimates 0 Small_woodland_birds night_light Initial
56 20.0 10.0 100 The community seems to do fine in suburban areas with street lighting. 10 Small_woodland_birds night_light Initial
59 0.2 0.0 10 while i do not have a strong background in this area, a quick search of overseas literature does suggest sublethal impacts of light exposure on songbirds. Impacts on native australian birds are unknown. Personal experience suggest most small woodland birds are not found in areas with lighting above that of streetlights, but that could be confounded by the fact that only very altered industrial areas with no tree/shrub cover are brightly lighted? 40 Small_woodland_birds night_light Initial
60 0.5 0.0 10 . 10 Small_woodland_birds night_light Initial
Aggregated 6.3 3.1 23 NA 14 Small_woodland_birds night_light Aggregated

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Maximum tolerable ambient temperature

This metric relates to the maximum ambient temperature which is associated with suitable habitat for this taxon group. Ambient temperature is the temperature which a mercury thermometer would record if it was suspended in the air out of direct sunlight (e.g. in the shade). This metric is likely to be relevant to larger terrestrial species, such as kangaroos, as well as arboreal species such as birds and bats.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 45 1 47 Given the basal temperature of most songbirds is between 36 and 44 degrees Celsius, once ambient temperature exceeds that, birds need to expend energy to cool themselves. These data are not available for most species of interest here, but are highly conserved at the order level, so published data on European and North American taxa are informative 66 Small_woodland_birds ambient_temp Initial
51 0 0 0 Too complex! Not a suitable metric for this exercise in my opinion. 0 Small_woodland_birds ambient_temp Initial
53 34 30 35

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the ambient temperature recorded in the shade during each of my bird surveys. I calculated the mean and maximum ambient temperature across all sites where small woodland birds were recorded. This metric was a little challenging as I didn’t survey in weather conditions where the ambient temperature was greater than 30 degrees. 		40 Small_woodland_birds ambient_temp Initial
54 36 35 40 Dont know literature here 60 Small_woodland_birds ambient_temp Initial
55 30 25 42 A guestimate, based on general field experience/observation and banding small birds in hot weather. Not based on studies of temperature effects. Birds seem able to tolerate extreme temps for limited periods. 60 Small_woodland_birds ambient_temp Initial
56 50 45 55 Birds seemed to cope OK with a run of days around 47-48 in 2018-19. 10 Small_woodland_birds ambient_temp Initial
59 35 0 45 Small birds can survive high temperatures for several days, but heat waves lasting more than a couple days are likely to result in nest failure, as adults will be unable to feed or incubate effectively at temperatures above their thermal limits (>40C). 90 Small_woodland_birds ambient_temp Initial
60 42 0 52 Straya is hot! 50 Small_woodland_birds ambient_temp Initial
Aggregated 34 17 40 NA 47 Small_woodland_birds ambient_temp Aggregated

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Habitat patch size and typical dispersal distances

The next series of visualisations relate to habitat patch size and typical dispersal distances.

This section asks questions regarding habitat patch sizes and typical dispersal distances for your selected taxon group.

Habitat patch size is explored for both core habitat (where the species lives full time) and corridors (areas the species might move through when dispersing, or when moving between connected habitat patches). Dispersal capability covers how far a species will typically move within and between habitat patches (e.g. within a home range), as well as how far they typically will move during a major dispersal event, e.g. when migrating or dispersing to a new home range.

The answers to these questions will help us to understand how far apart different patches of habitat can be whilst still being connected for a taxon group, as well as what the aspirations should be in terms of the total extent of connected habitat at the landscape or regional scale to facilitate typical dispersal patterns for the species. Below, we ask you to provide your upper, lower and best estimates for a range of metrics related to patch size and movement behaviour.

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Minimum suitable core habitat patch width

This metric relates to the minimum dimensions of an area which could be considered suitable core habitat for the taxon group. By core habitat, this would mean the area was able to provide all resources required by the species, including food, shelter, mates, etc.

For example, for a small mammal, the edge effects associated with a narrow strip of suburban woodland nestled between two rows of residential blocks may prevent it being classified as suitable core habitat. For an aquatic species, a stream may need to be some minimum width to provide sufficient core habitat for the species to move around in. If a core habitat patch in this instance is considered to have a rectangular shape, what would be the minimum width of the shorter side, regardless of how long the longer side might be?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 60 30 2000 I figure 30 metres is effectively one mature tree wide, like many roadside strips, which can support a surprising diversity of small birds. Ideally, two trees wide is a realistic minimum 60 Small_woodland_birds min_width_core Initial
51 0 0 0 Sorry - I need to revisit the literature on this one - can’t answer right now. My first point of call for this info will be Joern Fischer and his small remnant work. Very species specific - I actually think we should be using a handful of specialists/vulnerable woodland birds to create connectivity rules for this taxa… (food for thought) 0 Small_woodland_birds min_width_core Initial
53 12 10 15

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I referred to my catalogue of site photos to look at the average width of habitat patches. I also referred to my landscape-scale data on the maximum patch sizes in each of my study landscapes. These values were expressed as a patch size in hectares, but it was still useful to consider the patch sizes in landscapes where small woodland birds were recorded. 		50 Small_woodland_birds min_width_core Initial
54 50 20 100 The rarer birds would need alot more. Averagign makes this hard. 70 Small_woodland_birds min_width_core Initial
55 500 200 1000 A best estimate, based on experience bird surveying in various sized patches. This will vary widely depending on species, some tolerate small core patches, eg 2ha/circa 200 m, some require 10 ha or more. Breeding territories tend to be smaller than the all year round patch/territory required. 70 Small_woodland_birds min_width_core Initial
56 200 100 500 Based on recent observations around Canberra, I think the Western Gerygone and Rufous Whistler probably require the widest habitat patches. 50 Small_woodland_birds min_width_core Initial
59 200 60 1000 While the literature on minimum patch size for woodland bird persistence seems to suggest that total patch size needs to be >100ha in many cases, width and edge effects are not factors i am overly familiar with in urban settings. From observations in rural areas, linear strip widths of 200m or more with intact understory vegetation held the highest abundance of small woodland birds. 50-100m widths did sometimes contain less sensitive species. 50 Small_woodland_birds min_width_core Initial
60 15 2 20 Assumes native and non native vege 50 Small_woodland_birds min_width_core Initial
Aggregated 130 53 579 NA 50 Small_woodland_birds min_width_core Aggregated

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Minimum suitable corridor habitat patch width

This metric relates to the minimum dimensions of an area which could be considered suitable habitat for the taxon group to move through, e.g. between different patches of ‘core’ habitat, or when dispersing (e.g. as a sub-adult looking for a new home range). Corridor habitat would need to provide all resources required by the species to effectively move through the urban space, e.g. suitable perch sites for birds, suitable protection from predation for mammals and reptiles.

For example, for a small mammal, the edge effects associated with a narrow strip of suburban woodland nestled between two rows of residential blocks may prevent it being classified as suitable core habitat, but it might be sufficient habitat to facilitate movement through the area. For an aquatic species, a stream may need to be some minimum width to provide sufficient core habitat for the species to move around in, however the same species may be able to navigate a narrow culvert if just being used as part of a movement corridor. If a movement corridor in this instance is considered to have a rectangular shape, what would be the minimum width of the shorter side, regardless of how long the longer side might be?

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 500 50 5000 I have lived on a property that is a remnant of Grassy Box woodland, so have witnessed firsthand how many species come and go. Babblers, thornbills, honeyeaters, scrub wrens and robins. As work by Martine Maron demonstrated, species come and go from woodlands at a surprising rate, so they can clearly cover plenty of ground to get there 60 Small_woodland_birds min_width_corridor Initial
51 0 0 0 Not critical metric for this exercise 0 Small_woodland_birds min_width_corridor Initial
53 5 3 8

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I referred to my catalogue of site photos to look at the average width of habitat corridors. I also referred to my landscape-scale data on the maximum patch sizes in each of my study landscapes. These values were expressed as a patch size in hectares, but it was still useful to consider the patch sizes in landscapes where small woodland birds were recorded. 		60 Small_woodland_birds min_width_corridor Initial
54 30 5 50 Gogin off Canberra corridors. 60 Small_woodland_birds min_width_corridor Initial
55 50 10 200 In answering this, I drew on experience doing bird surveys in degraded landscapes, in re-vegetated/plantings in linear strips, roadside remnant veg strips, windbreaks. I have seen a range of small woodland birds moving along strip plantings or remnants, species depending on veg width and veg structure, Wider the corridor the bird diversity/species increases. Greening Aust ACT Region, Birdwatch program/Bringing Back Birds publication has useful information. 70 Small_woodland_birds min_width_corridor Initial
56 10 5 50 Most of the species are able to fly across substantial gaps (hundreds of metres or more) between trees. The species that may not be able to do this (Superb Fairy-wren and White-browed Scrubwren) are able to infiltrate suburban areas by moving from yard to yard. I’m not sure that this community requires movement "“corridors”" - the percentage of tree or understorey cover in a landscape may be a better indicator of landscape permeability for small woodland birds. 25 Small_woodland_birds min_width_corridor Initial
59 50 20 70 most woodland birds are fairly good dispersers, however, corridor distance should be short. White-browed scrubwrens typically only move 2km during juvenile dispersal, for example. 70 Small_woodland_birds min_width_corridor Initial
60 2 0 2 Lowest value is 0 as woodland birds can exit core habitat for movement 50 Small_woodland_birds min_width_corridor Initial
Aggregated 81 12 672 NA 49 Small_woodland_birds min_width_corridor Aggregated

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Typical dispersal distance when seeking new home range/territory

This metric describes how far dispersing individuals from this taxon group will travel, usually to find a new home range or territory. This metric assumes the availability of continuous habitat.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 1500 80 30000 Paul Sunnucks and co have looked at this explicitly with genetic data, but one and a half kilometres seems about right to me 50 Small_woodland_birds disperal_distance Initial
51 0 0 0 Sorry - too unsure. Some good work done here for Brown Treecreepers, which could arguable provide a defendable range given it is a sensitive woodland bird in our region… 0 Small_woodland_birds disperal_distance Initial
53 400 100 1000 This is outside the scope of my expertise. I have never studied the dispersal of any bird species, so I honestly don’t know how far small woodland birds could disperse. 0 Small_woodland_birds disperal_distance Initial
54 1000 200 2000 Some of these birds travel many kilometers. Don’t think value in guessing here. 60 Small_woodland_birds disperal_distance Initial
55 700 300 1000 A guestimate, not based on studies. Hard to answer as birds are highly mobile and will vary with species. In terms of resident species, some will disperse close to home or in neighbouring territories; some disperse across wider landscape. Upper value could be much higher for some species, and those in very low abundance across fragmented habitats (seeking breeding partners). 60 Small_woodland_birds disperal_distance Initial
56 500 200 1500 Dispersal distances vary hugely between the different species. 5 Small_woodland_birds disperal_distance Initial
59 500 200 2000 due to the highly variable dispersal abilities and territory sizes of woodland birds, this is a rough estimate based on wren behaviour 60 Small_woodland_birds disperal_distance Initial
60 1500 0 30000 Birds can disperse really far! Capped higher estimate at 30km to keep it within the ACT. 50 Small_woodland_birds disperal_distance Initial
Aggregated 762 135 8438 NA 36 Small_woodland_birds disperal_distance Aggregated

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Typical movement distance within established home range/territory

This metric describes how far an individual typically moves within a suitable habitat patch. It could be considered as the distance between the centre and the edge of a home range or territory.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 350 60 1000 There is some information available for some species, but this is so context dependent it will likely vary a bunch within species, let alone between them… 40 Small_woodland_birds movement_within Initial
51 0 0 0 Not enough work done to represent taxa/group. 0 Small_woodland_birds movement_within Initial
53 40 20 50 To derive my estimates, I drew on my prior bird survey experience in Melbourne. Whilst I have never studied the home ranges of any bird species, I felt somewhat confident in estimating how far a species would move around within its territory, based on repeatedly recording the same species at the same site over multiple visits. 30 Small_woodland_birds movement_within Initial
54 300 100 1000 Used average home range of a few woodland birds. 70 Small_woodland_birds movement_within Initial
55 700 300 1000 Similar to last answer. This is guestimate. Not based on any studies. In breeding season, territory/movement will be smaller. 60 Small_woodland_birds movement_within Initial
56 200 150 500 Again, there are big differences between the species. E.g. Mistletoebirds (which are rare in the ACT) probably have very big territories. 10 Small_woodland_birds movement_within Initial
59 500 200 1000 due to the highly variable dispersal abilities and territory sizes of woodland birds, this is a rough estimate based on wren behaviour 60 Small_woodland_birds movement_within Initial
60 450 250 1500 . 50 Small_woodland_birds movement_within Initial
Aggregated 318 135 756 NA 40 Small_woodland_birds movement_within Aggregated

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Typical capacity for movement outside of suitable habitat (in the absence of a physical barrier)

This metric aims to quantify how far this taxon group can or will typically move outside of areas mapped as suitable habitat. For example, a kangaroo might be able to cross a road, even though a road is not classified as suitable habitat, so long as there are no wildlife exclusion fences. A cockatoo might be able to move across a suburb between one suitable woodland habitat patch and another.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 5000 100 15000 The term describing these movements is Levi fights, and many woodland dependent species move many kilometres looking for potential real estate. 60 Small_woodland_birds capacity_movement Initial
51 0 0 0 Could assume same answers as mature tree distance. 0 Small_woodland_birds capacity_movement Initial
53 20 10 30 To derive my estimates, I drew on my prior bird survey experience in Melbourne. I have previously recorded small woodland birds in street trees in peri-urban Melbourne, but such street trees were often within 20m of a suitable patch of bushland. I’m not sure if these records would be considered normal for this group , so I don’t have much confidence in these estimates. 30 Small_woodland_birds capacity_movement Initial
54 300 200 1000 What is non habitat to a bird 60 Small_woodland_birds capacity_movement Initial
55 1000 500 10000 Not sure, guestimate. Birds as collective are highly mobile; seasonal species move long distances and over areas not suitable as habitat, following corridors of remnant trees/veg, creeklines etc, sometimes move at night. 60 Small_woodland_birds capacity_movement Initial
56 1000 500 5000 A guess. 5 Small_woodland_birds capacity_movement Initial
59 200 100 300 again, based on tracking studies, most small birds move only short distances outside suitable habitat, but this might be increased by paddock/street trees for some species 70 Small_woodland_birds capacity_movement Initial
60 150 0 30000 Birds can disperse super far! Capped upper estimate at 30km to keep within ACT. 50 Small_woodland_birds capacity_movement Initial
Aggregated 959 176 7666 NA 42 Small_woodland_birds capacity_movement Aggregated

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Barriers to movement

The next series of visualisations relate to barriers to movement.

This is the final section of this survey. This section asks questions regarding barriers to movement in the urban space, which might be represented by vertical barriers (fences, walls, buildings, gutters), water barriers (lakes, streams, rivers), substrate barriers (e.g. concrete or bitumen) or barriers relating to the use of an area by people (traffic, pedestrians). By quantifying these barriers we can use remote sensing data to identify their location in the urban environment and demonstrate functional habitat fragmentation.

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Maximum crossable extent of paved surface (incl. concrete drains)

This metric aims to capture the distance this taxon group can move across a paved surface, e.g. concrete or bitumen. Examples might include bike or pedestrian paths, roads and driveways, concrete drainage channels, tennis courts, car parks, etc. For reptiles, for example, a taxon group may choose this substrate as a basking site but not be able to move a long distance due to the lack of suitable habitat cover to protect from predation. For fish, platypus or turtles, there may be some maximum distance a species can move through an artificial waterbody (e.g. a concrete drainage channel) between naturalised pools or streams.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 300 30 3000 guesswork, and can’t visualise more than a few hundred metres of paved area except for an airport. Probably not nearly as relevant as tree based measures of distance… 20 Small_woodland_birds paved_surface Initial
51 0 0 0 Take answer from mature tree distance. High uncertainty. May be night/day dependent. 0 Small_woodland_birds paved_surface Initial
53 3 3 6 To derive my estimates, I drew on my prior bird survey experience in Melbourne. I have previously witnessed small woodland birds cross footpaths and roads in peri-urban areas of Melbourne. These paths and roads were often narrow and very quiet, with few pedestrians or cars. I feel this is a tricky metric to estimate as it it highly dependent on the surrounding habitat and the amount of noise disturbance. 30 Small_woodland_birds paved_surface Initial
54 40 15 100 Dont really know. 60 Small_woodland_birds paved_surface Initial
55 0 0 0 not important for birds 0 Small_woodland_birds paved_surface Initial
56 500 50 1000 Some of the species would be able to cross at least several km of paved surface; Scrubwrens and Fairy-wrens only 50-100 m. I have opted for 500 m as an "“average”". 25 Small_woodland_birds paved_surface Initial
59 200 50 300 again, based on tracking studies, most small birds move only short distances outside suitable habitat, but this might be increased by paddock/street trees for some species 70 Small_woodland_birds paved_surface Initial
60 250 0 500 Birds can disperse real far! Capped at 500m max as I can’t think of anywhere with more than 1km of paved surface width 50 Small_woodland_birds paved_surface Initial
Aggregated 162 18 613 NA 32 Small_woodland_birds paved_surface Aggregated

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Maximum crossable height of vertical structures

This metric aims to determine how much of a vertical structure will impede movement by this taxon group. For example, turtles may not be able to climb up a steep roadside curb, however for a gecko a vertical structure equivalent to a multi-storey building may not be prevent movement. Birds may be able to cross vertical barriers of any height, unless they are flightless.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 300 30 3000 Guesswork–not really an issue for birds, except for the brief interaction they increasingly have with shiny office towers 15 Small_woodland_birds max_height_building Initial
51 0 0 0 Not relevant 0 Small_woodland_birds max_height_building Initial
53 20 15 30 This is outside the scope of my expertise. I have previously witnessed Spotted Pardalotes disperse across a road/between patches of habitat at canopy tree height, but I’m not sure if they would be considered an outlier or normal for this group. Hence, I don’t have much confidence in these estimates. 10 Small_woodland_birds max_height_building Initial
54 60 30 1000 Not really reinvent. 60 Small_woodland_birds max_height_building Initial
55 0 0 0 Not important for birds 0 Small_woodland_birds max_height_building Initial
56 30 10 1000 Again, Scrubwrens and Fairy-wrens may struggle to get over something as high as 20 m, while other species can fly much higher. I’ve opted for an “average”. 25 Small_woodland_birds max_height_building Initial
59 0 0 0 maybe not a metric of concern for birds? i am assuming this does not apply to placement of buildings, just fences? 60 Small_woodland_birds max_height_building Initial
60 0 0 0 Birds may be able to cross vertical barriers of any height 0 Small_woodland_birds max_height_building Initial
Aggregated 51 11 629 NA 21 Small_woodland_birds max_height_building Aggregated

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Maximum crossable extent of water body

This metric aims to quantify the distance this taxon group can move across a permanent waterbody. In some instances, larger species such as kangaroos may be readily able to navigate a small stream by hopping from one side to the other, however the same might not be possible for a small grassland reptile.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 300 30 3000 again, not a core issue for the average woodland bird, me thinks 15 Small_woodland_birds max_waterbody Initial
51 0 0 0 Not relevant 0 Small_woodland_birds max_waterbody Initial
53 15 10 20 This is outside the scope of my expertise. I have never surveyed for birds adjacent to a large permanent waterbody (just narrow riparian corridors), so I honestly don’t know how far small woodland birds could fly across a body of water. 10 Small_woodland_birds max_waterbody Initial
54 30 20 100 Not sure. 50 Small_woodland_birds max_waterbody Initial
55 250 100 500 Guestimate. Not very relevant for mobile species like birds. I have seen variety of small birds fly across open water/rivers for several hundred metres; best estimate based on field obs. 60 Small_woodland_birds max_waterbody Initial
56 500 100 5000 Again, I’ve gone for an “average” value. 25 Small_woodland_birds max_waterbody Initial
59 200 100 300 again, based on tracking studies, most small birds move only short distances outside suitable habitat, but this might be increased during rare long distance dispersal 70 Small_woodland_birds max_waterbody Initial
60 5000 0 15000 Birds can fly really far! Capped at 15000 which is the length of Lake George 50 Small_woodland_birds max_waterbody Initial
Aggregated 787 45 2990 NA 35 Small_woodland_birds max_waterbody Aggregated

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Tolerable vehicle traffic flow (incl. boats) during active period (day/night)

This metric aims to quantify the level of vehicle traffic (including boats in an urban waterbody) which would represent a barrier to this taxon group. The number should be based on the amount of traffic occurring during the species’ active part of the day or night. For example, an echidna may be willing and able to cross a road at night when there is little traffic, however during the day an increased traffic volume may result in the road (or rather, the traffic on the road) becoming a barrier for this species. A similar approach can be applied to aquatic and riparian species in terms of boat traffic.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 0 0 0 n/a for woodland birds 15 Small_woodland_birds traffic_flow Initial
51 0 0 0 No idea. Nelida Vessinor (spelling!) may have considered Canberra road impacts on birds in her PhD… not sure… Karen Ikin could confirm. Karen Ikin and Darren Le Roux can also provide better estimates for the influence of urban features than I can. 0 Small_woodland_birds traffic_flow Initial
53 20 10 20

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the direct count of people per site visit and tried to remember what traffic flow was like in the suburbs where small woodland birds were most common. 		30 Small_woodland_birds traffic_flow Initial
54 0 0 200 Have low impact, but still zero would be best. 60 Small_woodland_birds traffic_flow Initial
55 0 0 0 Not important for birds 0 Small_woodland_birds traffic_flow Initial
56 3600 740 50000 Most of the species would just fly above vehicle level; however ground-dwellers like Scrubwrens may not. I’ve used a rate of 1 vehicle per second to estimate an "“average”" figure. 25 Small_woodland_birds traffic_flow Initial
59 400 300 1200 I have no experience in this area, literature is lacking, but i would guess that most birds could survive a 5-10 second gap between vehicles, hence my above estimates. 40 Small_woodland_birds traffic_flow Initial
60 0 0 0 Treated same as estimates for physical barriers - as birds can fly over traffic flow, there is no maximum number of vehicles per hour 0 Small_woodland_birds traffic_flow Initial
Aggregated 502 131 6428 NA 21 Small_woodland_birds traffic_flow Aggregated

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Tolerable pedestrian traffic flow (incl. swimming) during active periods (day/night)

This metric aims to quantify the level of pedestrian traffic (including swimmers in an urban waterbody) which would represent a barrier to this taxon group.The number should be based on the amount of pedestrians passing during the species’ active part of the day or night. A similar approach can be applied to aquatic and riparian species in terms of people swimming in a waterbody.

For example, a kangaroo may be willing and able to cross school playground at dusk in summer when there are few people about, however during winter an increased use of the school oval for organised sports in the evening may result in the grassy area becoming a barrier for this species.

Expert Best Lower Upper Comments Confidence Taxon Variable Group2
44 10 1 100 no idea 15 Small_woodland_birds pedestrian_flow Initial
51 0 0 0 No idea. Will be trait specific. To get to an average estimate, we’d want to do some work on proportion of Canberra small bird community that spend more time in overstorey (e.g. honeyeaters, martins, sitellas, some thornbills) vs near ground (warblers, finches, wrens, other thornbills)… 0 Small_woodland_birds pedestrian_flow Initial
53 30 20 60

To derive my estimates, I drew on my prior bird survey experience in Melbourne and referred to my PhD dataset of 1,500 bird surveys conducted at 300 sites across Greater Melbourne (5 visits per site x 300 sites = 1,500 surveys). I filtered my data to include only small woodland birds, such as Grey Fantails, Spotted Pardalotes, Superb Fairywrens, Weebills and White-browed Scrubwrens. In total, I recorded small woodland birds at 158 sites. For these 158 sites where small woodland birds were present, I looked at the recorded habitat characteristics of the site.

For this metric, I focused on the direct count of people per site visit. I calculated the average number of people encountered per hour for each suburb where small woodland birds were most common, and the average number of people encountered per hour in suburbs where small woodland birds were rarely recorded. 		70 Small_woodland_birds pedestrian_flow Initial
54 10 0 120 Hooded robins won’t bred if repeatable disturbed by people. In terms of movement no idea impacts. 60 Small_woodland_birds pedestrian_flow Initial
55 0 0 0 not important for birds 0 Small_woodland_birds pedestrian_flow Initial
56 1800 370 50000 Most of the species would just fly above head height; however ground-dwellers like Scrubwrens may not. I’ve used a rate of 1 person per two seconds to estimate an "“average”" figure. 25 Small_woodland_birds pedestrian_flow Initial
59 400 300 1200 similar to cars, small gaps in pedestrian activity should provide opportunities for gap crossing, so possibly not an issue for most woodland birds? 40 Small_woodland_birds pedestrian_flow Initial
60 0 0 0 Treated same as estimates for physical barriers - as birds can fly over traffic flow, there is no maximum number of vehicles per hour 0 Small_woodland_birds pedestrian_flow Initial
Aggregated 281 86 6435 NA 26 Small_woodland_birds pedestrian_flow Aggregated