Background

Questionnaire

Emmigration probability



Alternative Expert Minimum Plausible Most Likely Maximum Plausible Confidence
Status Quo BH 0.0e+00 0.1000000 0.5000000 70
BT 0.0e+00 0.0500000 0.1000000 95
BZ 0.0e+00 0.0100000 0.0200000 80
DF 0.0e+00 0.0000000 0.0001000 90
KF 0.0e+00 0.0300000 0.0500000 100
NM 5.0e-01 0.9000000 1.0000000 100
PT 1.0e-01 0.3000000 0.5000000 100
QP 0.0e+00 0.0000000 0.0100000 100
Aggregated 4.0e-07 0.1863754 0.9105496 95
Tītī town (Recruit to Tuteremoana) BT 5.0e-02 0.3000000 0.5000000 95
BZ 0.0e+00 0.0100000 0.0150000 80
DF 0.0e+00 0.5000000 0.8000000 91
KF 0.0e+00 0.0200000 0.0500000 100
NM 0.0e+00 0.1000000 0.3000000 100
PT 3.0e-01 0.4000000 0.5000000 100
QP 0.0e+00 0.0000000 0.0100000 100
Aggregated 8.6e-05 0.1937582 0.7534485 95
Tītī town (Recruit to other colonies) BT 0.0e+00 0.0500000 0.1000000 95
BZ 0.0e+00 0.0100000 0.0150000 80
DF 0.0e+00 0.0000000 0.0001000 90
KF 0.0e+00 0.0200000 0.0500000 100
NM 0.0e+00 0.1000000 0.3000000 100
PT 3.0e-01 0.4000000 0.5000000 100
QP 0.0e+00 0.0000000 0.0100000 100
Aggregated 1.1e-06 0.0871070 0.4855460 95
Weka fence plus BH 0.0e+00 0.0500000 0.2000000 100
BT 0.0e+00 0.0300000 0.1000000 95
BZ 0.0e+00 0.0100000 0.0150000 80
DF 0.0e+00 0.0000000 0.0001000 90
NM 5.0e-01 0.9000000 1.0000000 100
PT 1.0e-01 0.2000000 0.3000000 100
QP 0.0e+00 0.0000000 0.0100000 100
Aggregated 1.0e-07 0.1679371 0.9118353 95

Comments

Status Quo
  • DF: All procellariiformes are very phylopatric, the probability of emigration is extremely low and should probably be considered as an occasional phenomenon more than a usual habit
  • QP: Whatever low number of chicks manage to fledge from those that have hatched, first have to survive to adulthood (an achievement in itself) before they can return to this area of New Zealand. Is there a known percentage for fledged titi to return as adults? i.e. for fluttering shearwaters who don’t migrate this is less than 50%
  • NM: Natal recruitment is very low in this species. Expect most birds to disperse away from the main colony
Tītī town (Recruit to other colonies)
  • QP: depends on where new colony is located. If close to Tahoramaurea, a few may recruit there.
Tītī town (Recruit to Tuteremoana)
  • QP: unlikely if sound system in place at new location.
  • PT: Depends if you are playing acoustic lures at the main colony
  • NM: I would expect some fledglings to return to the lager colony on Kapiti. Probably more likely to congregate up top than in a new site as social dynamics plays a key role in site attraction
Weka fence plus
  • NM: Titi do not seem to have strong natal philopatry


Number of recruits



Alternative Expert Minimum Plausible Most Likely Maximum Plausible Confidence
Status Quo BH 0.0000000 2.000000 10.00000 50
BT 0.0000000 1.000000 3.00000 95
BZ 1.0000000 2.000000 3.00000 80
DF 0.0000000 0.500000 2.00000 90
KF 0.0000000 1.000000 3.00000 100
NM 1.0000000 10.000000 20.00000 100
PT 5.0000000 10.000000 15.00000 100
QP 0.0000000 0.000000 2.00000 100
Aggregated 0.0330978 4.278016 18.12129 95
Tītī town BT 0.0000000 1.000000 2.00000 95
BZ 3.0000000 5.000000 10.00000 80
DF 0.0000000 5.000000 10.00000 90
KF 0.0000000 0.500000 1.00000 100
NM 1.0000000 5.000000 10.00000 100
PT 5.0000000 10.000000 15.00000 100
QP 0.0000000 0.000000 5.00000 100
Aggregated 0.0834973 4.241821 16.17749 95
Weka fence plus BH 0.0000000 5.000000 30.00000 89
BT 0.0000000 2.000000 5.00000 95
BZ 3.0000000 7.500000 15.00000 80
DF 0.0000000 5.000000 10.00000 90
KF 0.0000000 0.500000 2.00000 100
NM 1.0000000 10.000000 20.00000 100
PT 10.0000000 15.000000 20.00000 100
QP 0.0000000 0.000000 2.00000 100
Aggregated 0.0629997 7.382980 30.96284 95

Comments

Status Quo
  • NM: There should be some birds arriving from other colonies to pair with birds that lost partners.

  • QP: Recruitment has two possible outcomes, permanent recruitment to a new location or “just visiting”. Just visiting may be for a single visit, a few weeks or a single season.

    I believe it is significant that several birds from Mana returned to Mana after visiting Tuteremoana. Any possible recruitment therefore may well not be permanent.

    In my limited experience, birds recruited to other colonies stay in the other colonies unless forced out. Of the 13 FS recruited to Matiu from Mana, only one returned when it was ejected from its burrow by penguins. It returned to Mana to breed. The remainder have established on Matiu and successfully breed there.
Tītī town
  • QP: Again depending on where it is located and with the sound system playing, it may well attract recruits into it.
  • NM: Would expect low levels of recruitment as its a new site and lacking attractive features that you find near the summit
Weka fence plus
  • NM: It is going to be a long slow rebuild. The titi translocation to Gap Sanctuary on Chathams should provide some early indications of how site faithful this species is. Also analysis of the recruitment rates on Mana Island.


Breeding probability



Alternative Expert Minimum Plausible Most Likely Maximum Plausible Confidence
Burrow modifications BH 0.6500000 0.8000000 0.9000000 100
BT 0.6300000 0.7900000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.5000000 0.6500000 0.8000000 90
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.5971176 0.7624748 0.8937934 95
Burrow modifications + supplementary feeding of weka BH 0.6500000 0.8000000 0.9000000 100
BT 0.6300000 0.7900000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.5000000 0.6500000 0.8000000 90
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6100000 0.7600000 0.8800000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.6016778 0.7607385 0.8885682 95
Burrow special BT 0.6300000 0.7900000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.6000000 0.7000000 0.8500000 90
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.6322376 0.7708298 0.8844014 95
Select weka BT 0.6500000 0.8000000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.5000000 0.6500000 0.8000000 86
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.5932717 0.7610466 0.8939648 95
Select weka + burrow modification BT 0.6500000 0.8000000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.6300000 0.7900000 0.9000000 89
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6100000 0.7600000 0.8800000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.6395060 0.7747915 0.8857626 95
Supplementary feeding of weka BH 0.6300000 0.7900000 0.9000000 100
BT 0.6300000 0.7900000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.2000000 0.3000000 0.5000000 90
KF 0.6300000 0.8000000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.3892147 0.7236906 0.9434409 95
Translocate weka BT 0.6500000 0.8000000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.5000000 0.6500000 0.8000000 86
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.6011381 0.7637983 0.8931344 95
Tītī town BT 0.4000000 0.7000000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.5500000 0.7000000 0.8500000 90
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.5624152 0.7511900 0.8982695 95
Weka deterrent BH 0.6000000 0.7900000 0.9000000 100
BT 0.6300000 0.7900000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.5000000 0.6500000 0.8000000 90
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7000000 0.9000000 100
PT 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.5931016 0.7551477 0.8859276 95
Weka deterrent + supplementary feeding BH 0.6300000 0.7900000 0.9000000 100
BT 0.6300000 0.7900000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.4000000 0.5000000 0.6000000 85
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.5199743 0.7447024 0.9122887 95
Weka fence BH 0.6500000 0.8000000 0.9000000 100
BT 0.7000000 0.8000000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.6000000 0.6500000 0.8000000 90
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6300000 0.7900000 0.9000000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.6360736 0.7732458 0.8854767 95
Weka fence plus BH 0.6500000 0.8000000 0.9000000 100
BT 0.7000000 0.8000000 0.9000000 95
BZ 0.6300000 0.7900000 0.9000000 95
DF 0.5500000 0.7000000 0.8500000 90
KF 0.6300000 0.7900000 0.9000000 100
NM 0.6300000 0.7900000 0.9000000 100
PT 0.6900000 0.8100000 0.9100000 100
QP 0.6300000 0.7900000 0.9000000 100
Aggregated 0.6368171 0.7765986 0.8897971 95

Comments

Burrow modifications
  • BH: If exclusion flaps result in less distrubance then probabilty of commiting to breeding may change, otherwise it is likely to remain the same.
  • NM: I don’t expect breeding probability to change as its driven by at sea factors. Provided the entrance flaps are not too tight and deterring birds from entering burrows the breeding probability should remain the same. If birds are put off by flaps then it would decrease.
  • QP: no change for egg laying
Supplementary feeding of weka
  • PT: This would not change the probability a female lays an egg
  • BH: Unlikley to change probability of egg laying
  • QP: adult titi probably can fight off a weka, it’s the young chicks that are predated. Supplementary feeding should have little effect on egg laying
  • NM: I don’t expect a change as its is determined by at-sea conditions
  • DF: Providing food to weka would be only a temporary solution. It would support an increase in the population of weka that would eventually increase the predation on titi, making it even harder for them to survive in the medium- to long-term
Weka deterrent
  • PT: Unfeasible due to high longterm cost and some management likely to have little effect. Weka are to smart for dumb stuff like this
  • NM: There is a possibility that peppermint oil could deter some titi. The birds use odour cues to find nests and strong peppermint oil could possibly disrupt those cues. Would need some testing done before it was trialled. Also need to see if it really does deter weka.
  • BH: If weka deterrent actions cause any disturbance to titi this may reduce their likelihood of committing to breeding.
Weka fence
  • PT: Yip would work but expensive option and especially in the long term with storm damage etc
  • NM: Breeding probability is largely driven by at-sea factors. However numbers of breeding birds should increase over time in this scenario.

Breeding success



Alternative Expert Minimum Plausible Most Likely Maximum Plausible Confidence
Burrow modifications BH 0.0020000 0.2500000 0.6700000 100
BT 0.0020000 0.0500000 0.1500000 95
BZ 0.2500000 0.3750000 0.5000000 95
DF 0.0020000 0.1700000 0.5000000 85
KF 0.0020000 0.1000000 0.6700000 100
NM 0.0000000 0.0500000 0.3000000 100
PT 0.1700000 0.3500000 0.6700000 100
QP 0.0020000 0.0500000 0.2000000 100
Aggregated 0.0121726 0.2090597 0.5749097 95
Burrow modifications + supplementary feeding of weka BH 0.0020000 0.2400000 0.6700000 100
BT 0.0020000 0.0500000 0.1500000 95
BZ 0.2500000 0.3750000 0.5000000 85
DF 0.0020000 0.1700000 0.5000000 85
KF 0.0020000 0.1500000 0.6700000 87
NM 0.0000000 0.1000000 0.3000000 100
PT 0.0500000 0.3000000 0.6500000 100
QP 0.0020000 0.0500000 0.2000000 100
Aggregated 0.0152299 0.2161533 0.5778532 95
Burrow special BT 0.0500000 0.2000000 0.5000000 95
BZ 0.2500000 0.4250000 0.6000000 90
DF 0.0020000 0.2100000 0.6700000 100
KF 0.0020000 0.1200000 0.6700000 100
NM 0.0500000 0.2000000 0.5000000 100
PT 0.0500000 0.2900000 0.6900000 100
QP 0.0020000 0.0200000 0.1000000 100
Aggregated 0.0173059 0.2408384 0.6191168 95
Select weka BT 0.0500000 0.3000000 0.6000000 95
BZ 0.2000000 0.3500000 0.5000000 90
DF 0.0020000 0.1700000 0.4000000 85
KF 0.0020000 0.1500000 0.6700000 100
NM 0.1000000 0.2500000 0.5000000 100
PT 0.1600000 0.3700000 0.6700000 100
QP 0.0020000 0.0200000 0.1000000 100
Aggregated 0.0210224 0.2543884 0.6293665 95
Select weka + burrow modification BT 0.0500000 0.3000000 0.6000000 95
BZ 0.3000000 0.5000000 0.7000000 90
DF 0.0020000 0.2100000 0.6700000 90
KF 0.0020000 0.2000000 0.6700000 100
NM 0.0500000 0.2600000 0.5000000 100
PT 0.1900000 0.4000000 0.6700000 100
QP 0.0020000 0.1000000 0.2000000 100
Aggregated 0.0467452 0.3089907 0.6783943 95
Supplementary feeding of weka BH 0.0050000 0.0500000 0.4000000 94
BT 0.0020000 0.0200000 0.0600000 95
BZ 0.0000000 0.0500000 0.1000000 90
DF 0.0000000 0.0400000 0.1000000 85
KF 0.0020000 0.1200000 0.6700000 100
NM 0.0000000 0.1000000 0.3000000 100
PT 0.0200000 0.1500000 0.6000000 100
QP 0.0020000 0.0500000 0.2000000 100
Aggregated 0.0063491 0.1092037 0.3319480 95
Translocate weka BT 0.0500000 0.3000000 0.6000000 95
BZ 0.2000000 0.3500000 0.5000000 90
DF 0.0020000 0.1700000 0.4000000 85
KF 0.0020000 0.1500000 0.6700000 100
NM 0.0500000 0.2000000 0.5000000 100
PT 0.1900000 0.4000000 0.6700000 100
QP 0.0020000 0.2500000 0.5000000 100
Aggregated 0.0712107 0.2861237 0.5738306 95
Tītī town BT 0.1500000 0.4500000 0.8000000 95
BZ 0.4500000 0.6000000 0.7500000 95
DF 0.0020000 0.2000000 0.6500000 90
KF 0.0020000 0.1000000 0.6700000 100
NM 0.0000000 0.0500000 0.3000000 100
PT 0.1900000 0.4000000 0.6700000 100
QP 0.0020000 0.0200000 0.1000000 100
Aggregated 0.0071767 0.2970245 0.8004105 95
Weka deterrent BH 0.0020000 0.0500000 0.4000000 100
BT 0.0200000 0.1000000 0.2000000 95
BZ 0.0000000 0.0500000 0.1000000 95
DF 0.0020000 0.2000000 0.5000000 90
KF 0.0020000 0.0300000 0.6700000 100
NM 0.0000000 0.0500000 0.3000000 100
PT 0.0500000 0.2500000 0.6700000 100
QP 0.0020000 0.0200000 0.1000000 100
Aggregated 0.0057779 0.1301194 0.4060448 95
Weka deterrent + supplementary feeding BH 0.0050000 0.0900000 0.4000000 94
BT 0.0200000 0.1000000 0.2000000 95
BZ 0.0000000 0.0500000 0.1000000 90
DF 0.0020000 0.1000000 0.2000000 85
KF 0.0020000 0.0800000 0.6700000 100
NM 0.0000000 0.1000000 0.3000000 100
PT 0.0020000 0.2700000 0.6700000 100
QP 0.0020000 0.0200000 0.1000000 100
Aggregated 0.0088121 0.1338553 0.3915809 95
Weka fence BH 0.0020000 0.2500000 0.6700000 100
BT 0.2000000 0.4500000 0.7500000 95
BZ 0.4500000 0.6000000 0.7500000 95
DF 0.0020000 0.1900000 0.6000000 90
KF 0.0020000 0.0800000 0.6700000 74
NM 0.2000000 0.5000000 0.7500000 100
PT 0.1900000 0.4000000 0.6700000 100
QP 0.0020000 0.3000000 0.8000000 100
Aggregated 0.0743680 0.3865444 0.7619840 95
Weka fence plus BH 0.0020000 0.2500000 0.6700000 100
BT 0.2500000 0.5000000 0.8000000 95
BZ 0.4500000 0.6000000 0.7500000 95
DF 0.0020000 0.2000000 0.6500000 90
KF 0.0020000 0.1500000 0.6700000 50
NM 0.2000000 0.5000000 0.7500000 100
PT 0.1900000 0.4000000 0.6700000 100
QP 0.0020000 0.3000000 0.8000000 100
Aggregated 0.0839990 0.3985042 0.7675065 95

Comments

Burrow modifications
  • DF: Breeding success would increase but would not reach the same as where weka is not present as we can assume some burrows will fail protection and some birds would still be breeding in natural burrows, hence susceptible to protection
  • QP: Weka are cunning (clever) birds. After a short period of time they will learn how to get around the weka exclusion flap.
  • NM: Sadly it seems weka know how to enter these burrows and with flaps alone I don’t think it is going to stop determined individual weka getting into burrows
Burrow modifications + supplementary feeding of weka
  • NM: I think feeding will distract some birds and modified burrows will make it less likely inexperienced birds will enter nests if they have easer food available
Burrow special
  • NM: It would be a demanding project and probably would increase chick production. But surely there are cheaper and easier alternatives. Just annually remove all the weka near the titi burrows in Nov-Dec. I think that will make a big difference.
Select weka

  • QP: Not a long term solution as weka will reinvade the colony area as existing weka are removed from it. This will need to continue year after year.

    Lots of effort needed to catch and then remove weka (if alive carry them down the hill) and then care for them while they are on their journey to a new home location.

    What if you miss removing one weka that predates on chicks? this weka could kill many chicks before it is identified and/or captured.
  • NM: I think this is the best and most practical option. Remove all weka annually with knowledge of the burrows and titi chicks. Some new birds will arrive and learn to take chicks. But I would expect significant improvements on status quo
Select weka + burrow modification
  • NM: removing weka and modifying burrows should further enhance breeding success
Supplementary feeding of weka
  • NM: I think there could be a net gain in breeding success as the less experienced weka will be distracted by the feeders and would be less interested in burrows. The old experienced weka are likely to keep taking chicks as they provide a valuable nutritional reward. I think if all the local weka were culled and supplementary food was provided around Jan/Feb period this method may actually work

  • QP: Titi chicks do not cause a danger to weka during predation so even with supplementary feeding weka will still harvest Titi chicks.

    With a more healthy weka population from supplementary feeding, predation may even increase because more weka survive the winter due to being fatter.
  • PT: Any benefit could be offset by higher weka densities at the site plus long term this is a costly and expensive management option
  • DF: Supplementary feeding is only a temporary measure as it will support an increase of weka that would eventually increase the predation on titi
Tītī town
  • NM: Sadly probably wont change much at all from status quo

  • QP: This option is basically abandoning Tuteremoana to its extinction within a few years. There is a reason why titi choose this location. Any alternative location is less preferred by them.

    Translocating chicks from Tuteremoana to the new location removes chicks from there. They will need to be protected at Tuteremoana until transferred and then fed at the new location until they fledge.

    This option involves a lot a work and it will be 5-10 years before progress will be seen as fledglings will take several years before they return and then build up sufficient numbers to be viable. 240 FS chicks translocated to Matiu over 3 years between 2012-2014. In 2025, 100 FS adults are now resident there. Similar story for Mana FS translocation. And this proposal is talking about smaller numbers of translocated chicks.

Translocate weka
  • NM: Removing weka familiar with the burrows will help titi. However not sure translocation is going to work for weka. When this was done on Whenua Hou. the birds tried to swim back and most drowned. Would need a major captive holding project to break down territory behaviour followed by release into suitable habitat (Queen Elizabeth Park)?

  • QP: If titi predation is a learned behaviour, this is one of the best alternatives.

    It also provides an ongoing source of birds to iwi for another colony establishment project elsewhere or eating.
Weka deterrent
  • NM: Not really convinced that weka could be deterred. If they have strong reason to enter a burrow ( a fat chick inside) they would habituate to most calls and smells. Guarding nests sounds good in theory but would it be sustainable within a season and across years

  • QP: Though these efforts are directed at weka, what effect will they have on titi? Will the peppermint oil smell affect them? Do karearea predate titi and will hearing their calls cause stress on titi? will it attract karearea to the colony? will they predate titi chicks?

    Manually checking of burrows twice daily is extremely labour intensive and hardly a viable long tern solution. To be done in wet storming weather as well as fine conditions, trudging up to the summit of Kapiti Island twice daily????
Weka deterrent + supplementary feeding
  • NM: Likely to be an improvement but seems to be a labour intensive method
Weka fence
  • BH: Complete exclusion of weka should provide similar conditions to those present on weka-free colonies like Mana.

  • QP: A weka exclusion fence should not be as difficult or expensive to construct as a general predator exclusion fence as it is targeting a specific species not a range of species.

    The weka fence needs to be enclose a reasonably large area so titi don’t land on the wrong side of it and build burrows outside the enclosure.
  • NM: I would expect it to be similar to Mana, possibly slightly higher as the peat soil is less prone to flooding
Weka fence plus
  • NM: Sound may lure in extra birds and speed up numbers breeding but unlikely to alter breeding success
  • QP: The enclosed area needs to be big enough that attracted birds do not land outside the fence and establish burrows there (remember Chatham Petrels at Sweetwater). Think long term when there is an expanding colony present that will need a larger area, not just a small area for the protection of the present colony.