Introduction

(About this document: This is an R notebook. As such, it is very informal and contains lots of typos and poorly constructed fragment sentences. It’s purpose is to generate converstation among staff. It’s not suitable for publishing in the Daily Camera.)

Reading in a file of bird sampling along line transects and looking through it to understand its dimension. This file will be used to compare some different approaches to converting the raw observation data for the decay in detection probability from an observation. In principle, this inflates the value of detection that are far from the observer.

options(stringsAsFactors = FALSE)
library(readxl)
## Warning: package 'readxl' was built under R version 3.6.2
d <- read_excel('S:/OSMP/ECO_SYSTEMS/WILDLIFE/BIRDS/Distance data analysis/qry.GMAPAllSpp.No.FO.wDistance.and.EnivroData.2017thru2019.xlsx')
names(d)
##  [1] "Sample_name"     "Property"        "Year"           
##  [4] "BirdSpp"         "Number"          "Date"           
##  [7] "Distance"        "Angle"           "DetectionType"  
## [10] "Comments"        "CloudIndexBegin" "WindIndexBegin" 
## [13] "NoiseIndexBegin" "Description"

The first 8 variables are the main ones of interest. Cloud, Wind, and Noise are covariates that could be used to change the detection probability. I’m not sure what DetectionType is.

Looking at one variable at a time

Next, we’ll step through each one to get a sense of the study design.

Sample_name

table(d$Sample_name)
## 
##  AWBM-96  AWBM-97 BWBM-100 BWBM-101  DVBM-98  DVBM-99 EBBM-102 EBBM-103 
##       28       39       46       28       39       29       62       23 
##  EBBM-66  EBBM-67  EBBM-68  EBBM-69  EBBM-70  EBBM-71  EBBM-72  EBBM-73 
##       35       29       35       51       46       42       39       31 
##  EBBM-74  EBBM-75  ETBM-01  ETBM-02 GHBM-104 GHBM-105 GHBM-106 GHBM-107 
##       32       42       33       40       34       29       43       46 
##  GHBM-32  GHBM-33  GHBM-34  GHBM-35  GHBM-36  GHBM-37  GHBM-38  GHBM-39 
##       36       33       40       29       26       24       39       31 
## IBMBM-50 IBMBM-51   JBM-01   JBM-02   JBM-03  JFBM-52  JFBM-53  JFBM-54 
##       32       35       24       48       34       16       15       34 
##  JMBM-10  JMBM-11  JMBM-12  JMBM-14  JMBM-15  JMBM-16  JMBM-17  JMBM-18 
##       50       42       38       35       43       40       26       25 
##  JMBM-19  JMBM-91  JMBM-92  JMBM-93  JMBM-94  JMBM-95  NBBM-20  NBBM-21 
##       29       40       31       54       31       40       46       57 
##  NBBM-22  NBBM-23  NBBM-24  NBBM-25  NBBM-26  NBBM-27  NBBM-28  NBBM-30 
##       44       34       28       27       32       46       35       34 
##  NBBM-31  NBBM-76  NBBM-77  NBBM-78  NBBM-79  NBBM-80  PGBM-01  PGBM-02 
##       47       57       30       51       47       55       32       39 
##  PGBM-03  PGBM-04  PGBM-05  PGBM-06  PGBM-07  PGBM-08  PGBM-09 PGBM-108 
##       40       44       35       45       43       48       44       46 
## PGBM-109 PGBM-110  SGBM-40  SGBM-41  SGBM-42  SGBM-43  SGBM-44  SGBM-45 
##       53       66       38       44       51       39       38       58 
##  SGBM-46  SGBM-47  SGBM-60  SGBM-61  SGBM-81  SGBM-82  SGBM-83  SGBM-84 
##       31       38       34       42       47       47       40       31 
##  SGBM-85  SGBM-86  SGBM-87  SGBM-88  SGBM-89  SGBM-90  STBM-58  STBM-59 
##       33       43       36       64       42       56       56       64 
##  TGWB-04  TGWB-15  TGWB-20  TGWB-21  TGWB-23  TGWB-24  TGWB-26  TGWB-27 
##       32       34       36       48       35       36       38       30 
##  TGWB-28  TGWB-29  TGWB-30  TGWB-31  TGWB-32  TGWB-34  TGWB-35  WBBM-55 
##       32       39       30       38       43       38       44       29 
##  WBBM-56  WBBM-57 
##       61       55
length(table(d$Sample_name))
## [1] 122

122 different samples. The 4 character code appears to concatenate two different things. Guessing property, and then the 2nd set of 2 vary between BM and WB. Not sure what those are yet.

The number of records per sample varies from around 16 to over 60.

Property

table(d$Property)
## 
##           Aweida II   Boulder Warehouse        Damyanonvich 
##                  67                  74                  68 
##          East Beech            Ertl III      Gunbarrel Hill 
##                 467                  73                 410 
##                 IBM               Jafay          Jewell Mt. 
##                  67                  65                 524 
##               Joder       North Boulder Southern Grasslands 
##                 106                 670                 852 
##           Steinbach      Tallgrass West           West Rudd 
##                 120                 553                 535 
##      Woods Brothers 
##                 145

About 16 different properties. Indeed, these seem to correspond the the 1st two characters of the Sample_name.

Some properties have way more observations than others, probably due to an unbalanced distribution of transects (i.e., more transects at West Rudd than IBM). We can check that assumption later.

Year

table(d$Year)
## 
## 2017 2018 2019 
## 1641 1553 1602

Three different years, relatively equal number of observations.

BirdSpp

sort(table(d$BirdSpp))
## 
##           AMBI           BAEA           BANS           BRSP           BRTH 
##              1              1              1              1              1 
##           CANG           COHA           DICK           GBHE           GOEA 
##              1              1              1              1              1 
##           GRCA           GTGR           HAWO           INBU           MOBL 
##              1              1              1              1              1 
##           OCWA           PEFA           PYNU           RECR           SOSP 
##              1              1              1              1              1 
##           SWHA UNK FLYCATCHER           WEKE           WESJ           YRWA 
##              1              1              1              1              1 
##           AMCR           BUOW           CASP           LARB           MERL 
##              2              2              2              2              2 
##           NRWS           WCSP           CHSP           CORA           DEJU 
##              2              2              3              3              3 
##           WAVI           BHGR           TRES           BCCH           WETA 
##              3              4              4              5              5 
##           HOSP           EUCD           KILL           COYE           MALL 
##              6              7              7              8              8 
##           ROPI           VGSW           EAKI           ECDO           CONI 
##              8              9             10             10             11 
##           NOFL           AMGO           BLJA           ROWR           CLSW 
##             11             12             12             13             15 
##           BARS           BHCO           GTTO           SAPH           WEWP 
##             16             16             16             16             16 
##           AMKE           BGGN            UNK           HOFI           BUOR 
##             17             17             18             21             23 
##           YWAR           BLGR           BTAH           LEGO           RTHA 
##             23             24             29             29             30 
##           COGR           BRBL           YBCH           EUST           WEKI 
##             32             39             41             49             49 
##           HOWR           MODO           LAZB           AMRO           RWBL 
##             52             52             53             81            128 
##           BBMA           HOLA           LASP           SPTO           GRSP 
##            147            151            169            215            408 
##           VESP           WEME 
##            767           1836
length(table(d$BirdSpp))
## [1] 87

87 different species, with a lot of rare detections (i.e., birds with only one record). Really, almost all the data is WEME and VESP. We should keep that in mind as we go forward. According to the Bird Conservancy of the Rockies (or whatever they are called), you need at least 70 records per species for the distance analysis. In this dataset, that would leave us with just 9 species. If we subset our data to just keep these 9, I wonder how it will affect the overall design, in terms on number of transects and properties sampled?

Number

plot(table(d$Number))

Almost all the records have a Number value of one, as expected (single bird observed). One crazy record has a count of 85, a big flock of birds apparently. This will be important to think about as we get into modeling. I wonder what this looks like if we focus on our top 9 species only? We’ll see later.

Date

table(d$Date)
## 
## 2017-05-22 2017-05-23 2017-05-24 2017-05-25 2017-05-26 2017-05-30 
##        119        145        126        151        143         87 
## 2017-05-31 2017-06-02 2017-06-19 2017-06-20 2017-06-21 2017-06-22 
##         48         34        174        175        181        131 
## 2017-06-26 2017-06-28 2018-05-28 2018-05-29 2018-05-30 2018-05-31 
##         94         33         88         91        165        263 
## 2018-06-01 2018-06-11 2018-06-12 2018-06-13 2018-06-14 2018-06-15 
##        146         88        216        193        257         46 
## 2019-01-01 2019-06-03 2019-06-04 2019-06-05 2019-06-06 2019-06-17 
##          2        153        249        177        173        150 
## 2019-06-18 2019-06-19 2019-06-20 2019-06-21 
##        274        213        168         43
length(table(d$Date))
## [1] 34

34 different dates, with 14 in 2017, 10 in 2018, and 10 in 2019. Unbalance among years. Also, note a big range in observations per date. One weird looking date of Jan 1, 2019; guessing that is an error? Also note that no observations were done in May of 2019.

Distance

plot(table(d$Distance))

median(d$Distance, na.rm = T)
## [1] 76

Median distance is 76 (meters?). Left skewed (non-normal) distribution, as I would have expected.

Note, there are some NA values in the dataset that need to be dealt with. Let’s see how many.

length(which(is.na(d$Distance)))
## [1] 175

That’s a lot! What’s the deal?

Angle

plot(table(d$Angle))

It appears that the valid range of values for Angle is 0 to 90. So, we have about 5 values that above 90. Remove/fix? Also, I’d like to know why only 90 degrees is the search area…

DetectionType

table(d$DetectionType)
## 
##       C     C,S   C,S,V     C,V  C,V,FT   C,V,S      FT   FT, V    FT,0 
##     176       5       5     221       2       5      78       1       1 
##    FT,C  FT,C,V    FT,O    FT,V  FT,V,C       O    O,FT       S     S,C 
##       8       5       3      26      18       2       1    1263      78 
##   S,C,V     S,V   S,V,C  S,V,FT     S.C     SCV       V    V, C   V, FT 
##      67     604       8       1       1       1    1143       2       1 
## V, S, C     V,C  V,C,FT   V,C,S    V,FT     V,O     V,S   V,S,C     V.S 
##       1     479       3      52      30       1     406      84       1 
##      VS 
##       1

I don’t know what this variable is, but could speculate (I won’t tho). Whatever it is, it’s a bit crazy in the number of levels and variability in formatting. I’m ignoring this for now.

Cloud, Wind, Noise

table(d$CloudIndexBegin)
## 
##    0    1    2    3    4    5    6 
##  921 1627  698  487  518  502   43
table(d$WindIndexBegin)
## 
##    0    1    2    3    4 
##  574 1949 1430  655  188
table(d$NoiseIndexBegin)
## 
##    0    1    2    3    4    5 
##   68  960 1803 1303  660    2

I’m guessing higher values mean more clouds, wind, and noise, and therefore poorer detection. I also notice that each variable has a different maximum value… Can field observers reliably distinguish 7 levels of cloudiness? I suppose it’s possible. Do the functions to calculate distance-corrected density take covariates that are binned like these? Do the covariates need to have the same number of levels? We shall see.

Description

table(d$Description)
## 
##                   Aweida Bird Monitoring 96 
##                                          28 
##                   Aweida Bird Monitoring 97 
##                                          39 
##       Boulder Warehouse Bird Monitoring 100 
##                                          46 
##       Boulder Warehouse Bird Monitoring 101 
##                                          28 
##              Damyanovich Bird Monitoring 98 
##                                          39 
##              Damyanovich Bird Monitoring 99 
##                                          29 
##              East Beech Bird Monitoring 102 
##                                          62 
##              East Beech Bird Monitoring 103 
##                                          23 
##               East Beech Bird Monitoring 66 
##                                          35 
##               East Beech Bird Monitoring 67 
##                                          29 
##               East Beech Bird Monitoring 68 
##                                          35 
##               East Beech Bird Monitoring 69 
##                                          51 
##               East Beech Bird Monitoring 70 
##                                          46 
##               East Beech Bird Monitoring 71 
##                                          42 
##               East Beech Bird Monitoring 72 
##                                          39 
##               East Beech Bird Monitoring 73 
##                                          31 
##               East Beech Bird Monitoring 74 
##                                          32 
##               East Beech Bird Monitoring 75 
##                                          42 
##                Ertl Three Bird Monitoring 1 
##                                          33 
##                Ertl Three Bird Monitoring 2 
##                                          40 
##          Gunbarrel Hill Bird Monitoring 104 
##                                          34 
##          Gunbarrel Hill Bird Monitoring 105 
##                                          29 
##          Gunbarrel Hill Bird Monitoring 106 
##                                          43 
##          Gunbarrel Hill Bird Monitoring 107 
##                                          46 
##           Gunbarrel Hill Bird Monitoring 32 
##                                          36 
##           Gunbarrel Hill Bird Monitoring 33 
##                                          33 
##           Gunbarrel Hill Bird Monitoring 34 
##                                          40 
##           Gunbarrel Hill Bird Monitoring 35 
##                                          29 
##           Gunbarrel Hill Bird Monitoring 36 
##                                          26 
##           Gunbarrel Hill Bird Monitoring 37 
##                                          24 
##           Gunbarrel Hill Bird Monitoring 38 
##                                          39 
##           Gunbarrel Hill Bird Monitoring 39 
##                                          31 
##                      IBM Bird Monitoring 50 
##                                          32 
##                      IBM Bird Monitoring 51 
##                                          35 
##                    Jafay Bird Monitoring 52 
##                                          16 
##                    Jafay Bird Monitoring 53 
##                                          15 
##                    Jafay Bird Monitoring 54 
##                                          34 
##          Jewell Mountain Bird Monitoring 10 
##                                          50 
##          Jewell Mountain Bird Monitoring 11 
##                                          42 
##          Jewell Mountain Bird Monitoring 12 
##                                          38 
##          Jewell Mountain Bird Monitoring 14 
##                                          35 
##          Jewell Mountain Bird Monitoring 15 
##                                          43 
##          Jewell Mountain Bird Monitoring 16 
##                                          40 
##          Jewell Mountain Bird Monitoring 17 
##                                          26 
##          Jewell Mountain Bird Monitoring 18 
##                                          25 
##          Jewell Mountain Bird Monitoring 19 
##                                          29 
##          Jewell Mountain Bird Monitoring 91 
##                                          40 
##          Jewell Mountain Bird Monitoring 92 
##                                          31 
##          Jewell Mountain Bird Monitoring 93 
##                                          54 
##          Jewell Mountain Bird Monitoring 94 
##                                          31 
##          Jewell Mountain Bird Monitoring 95 
##                                          40 
##                     Joder Bird Monitoring 1 
##                                          24 
##                     Joder Bird Monitoring 2 
##                                          48 
##                     Joder Bird Monitoring 3 
##                                          34 
##            North Boulder Bird Monitoring 20 
##                                          46 
##            North Boulder Bird Monitoring 21 
##                                          57 
##            North Boulder Bird Monitoring 22 
##                                          44 
##            North Boulder Bird Monitoring 23 
##                                          34 
##            North Boulder Bird Monitoring 24 
##                                          28 
##            North Boulder Bird Monitoring 25 
##                                          27 
##            North Boulder Bird Monitoring 26 
##                                          32 
##            North Boulder Bird Monitoring 27 
##                                          46 
##            North Boulder Bird Monitoring 28 
##                                          35 
##            North Boulder Bird Monitoring 30 
##                                          34 
##            North Boulder Bird Monitoring 31 
##                                          47 
##            North Boulder Bird Monitoring 76 
##                                          57 
##            North Boulder Bird Monitoring 77 
##                                          30 
##            North Boulder Bird Monitoring 78 
##                                          51 
##            North Boulder Bird Monitoring 79 
##                                          47 
##            North Boulder Bird Monitoring 80 
##                                          55 
##   Paragliding (West Rudd) Bird Monitoring 1 
##                                          32 
## Paragliding (West Rudd) Bird Monitoring 108 
##                                          46 
## Paragliding (West Rudd) Bird Monitoring 109 
##                                          53 
## Paragliding (West Rudd) Bird Monitoring 110 
##                                          66 
##   Paragliding (West Rudd) Bird Monitoring 2 
##                                          39 
##   Paragliding (West Rudd) Bird Monitoring 3 
##                                          40 
##   Paragliding (West Rudd) Bird Monitoring 4 
##                                          44 
##   Paragliding (West Rudd) Bird Monitoring 5 
##                                          35 
##   Paragliding (West Rudd) Bird Monitoring 6 
##                                          45 
##   Paragliding (West Rudd) Bird Monitoring 7 
##                                          43 
##   Paragliding (West Rudd) Bird Monitoring 8 
##                                          48 
##   Paragliding (West Rudd) Bird Monitoring 9 
##                                          44 
##      Southern Grasslands Bird Monitoring 40 
##                                          38 
##      Southern Grasslands Bird Monitoring 41 
##                                          44 
##      Southern Grasslands Bird Monitoring 42 
##                                          51 
##      Southern Grasslands Bird Monitoring 43 
##                                          39 
##      Southern Grasslands Bird Monitoring 44 
##                                          38 
##      Southern Grasslands Bird Monitoring 45 
##                                          58 
##      Southern Grasslands Bird Monitoring 46 
##                                          31 
##      Southern Grasslands Bird Monitoring 47 
##                                          38 
##      Southern Grasslands Bird Monitoring 60 
##                                          34 
##      Southern Grasslands Bird Monitoring 61 
##                                          42 
##      Southern Grasslands Bird Monitoring 81 
##                                          47 
##      Southern Grasslands Bird Monitoring 82 
##                                          47 
##      Southern Grasslands Bird Monitoring 83 
##                                          40 
##      Southern Grasslands Bird Monitoring 84 
##                                          31 
##      Southern Grasslands Bird Monitoring 85 
##                                          33 
##      Southern Grasslands Bird Monitoring 86 
##                                          43 
##      Southern Grasslands Bird Monitoring 87 
##                                          36 
##      Southern Grasslands Bird Monitoring 88 
##                                          64 
##      Southern Grasslands Bird Monitoring 89 
##                                          42 
##      Southern Grasslands Bird Monitoring 90 
##                                          56 
##                Steinbach Bird Monitoring 58 
##                                          56 
##                Steinbach Bird Monitoring 59 
##                                          64 
##           Tallgrass West Bird Monitoring 04 
##                                          32 
##           Tallgrass West Bird Monitoring 15 
##                                          34 
##           Tallgrass West Bird Monitoring 20 
##                                          36 
##           Tallgrass West Bird Monitoring 21 
##                                          48 
##           Tallgrass West Bird Monitoring 23 
##                                          35 
##           Tallgrass West Bird Monitoring 24 
##                                          36 
##           Tallgrass West Bird Monitoring 26 
##                                          38 
##           Tallgrass West Bird Monitoring 27 
##                                          30 
##           Tallgrass West Bird Monitoring 28 
##                                          32 
##           Tallgrass West Bird Monitoring 29 
##                                          39 
##           Tallgrass West Bird Monitoring 30 
##                                          30 
##           Tallgrass West Bird Monitoring 31 
##                                          38 
##           Tallgrass West Bird Monitoring 32 
##                                          43 
##           Tallgrass West Bird Monitoring 34 
##                                          38 
##           Tallgrass West Bird Monitoring 35 
##                                          44 
##           Woods Brothers Bird Monitoring 55 
##                                          29 
##           Woods Brothers Bird Monitoring 56 
##                                          61 
##           Woods Brothers Bird Monitoring 57 
##                                          55

Description seems to be a concatenation of several of the previous variables. It also shows us what some of the code values in Sampe_name mean; e.g., PG = Paragliding.

Summary

So, here’s what we know so far:

  • 122 different samples
  • 3 years (with relatively equal # of obs per year, but unbalanced number of outings/dates per year)
  • Missed May sampling in 2019
  • 87 species (with 9 with > 70 records)
  • Oddities
    • 1 really large Number value (n=85)
    • 1 Date error
    • 175 NA values for Distance.

Identify the comparisons of interest

The point of the distance analysis is to calculate density estimates and variance for those estimates for groups of interest. What are the groups we’d be wanting to compare here? I think there’s just two possibilities:

  • Year n = 3
  • Property n = 16

A third group might be the WB and BM values that are seen in the Sample_name, but I don’t know what those are.

Would we want to compare all 16 properties, or drop some of the less sampled ones? Let’s look at number of transects per property.

lapply(split(d, d$Property), function(x){
  length(unique(x$Sample_name))
})
## $`Aweida II`
## [1] 2
## 
## $`Boulder Warehouse`
## [1] 2
## 
## $Damyanonvich
## [1] 2
## 
## $`East Beech`
## [1] 12
## 
## $`Ertl III`
## [1] 2
## 
## $`Gunbarrel Hill`
## [1] 12
## 
## $IBM
## [1] 2
## 
## $Jafay
## [1] 3
## 
## $`Jewell Mt.`
## [1] 14
## 
## $Joder
## [1] 3
## 
## $`North Boulder`
## [1] 16
## 
## $`Southern Grasslands`
## [1] 20
## 
## $Steinbach
## [1] 2
## 
## $`Tallgrass West`
## [1] 15
## 
## $`West Rudd`
## [1] 12
## 
## $`Woods Brothers`
## [1] 3

Large range in number of samples per property, likely reflecting different property sizes? As a result, we may end up with high variance for some of these poorly sampled properties, making it difficult to accurately describe differences among them. Are any of these properties adjacent and could therefore be combined? Are there other groupings of interest, like grassland conservation target and land use history, that we should investigate?

For Year, let’s look to make sure that each Sample_name was monitored in each year.

table(d$Sample_name, d$Year)
##           
##            2017 2018 2019
##   AWBM-96     9    9   10
##   AWBM-97     9   16   14
##   BWBM-100   13   12   21
##   BWBM-101    9    9   10
##   DVBM-98    18   11   10
##   DVBM-99    12    8    9
##   EBBM-102   23   16   23
##   EBBM-103    7    8    8
##   EBBM-66    13   16    6
##   EBBM-67    10   12    7
##   EBBM-68    11   17    7
##   EBBM-69    17   25    9
##   EBBM-70    20   14   12
##   EBBM-71    17   13   12
##   EBBM-72    14   16    9
##   EBBM-73    17    9    5
##   EBBM-74    12   12    8
##   EBBM-75    13   15   14
##   ETBM-01    10    7   16
##   ETBM-02    16   13   11
##   GHBM-104   15   12    7
##   GHBM-105   12    5   12
##   GHBM-106   19   16    8
##   GHBM-107   20   12   14
##   GHBM-32    18    9    9
##   GHBM-33    12   12    9
##   GHBM-34    15   17    8
##   GHBM-35     9    9   11
##   GHBM-36     9   10    7
##   GHBM-37    12    6    6
##   GHBM-38    17   14    8
##   GHBM-39    15    9    7
##   IBMBM-50    8   10   14
##   IBMBM-51   12   12   11
##   JBM-01      8    6   10
##   JBM-02     16   14   18
##   JBM-03     14    8   12
##   JFBM-52     9    7    0
##   JFBM-53     6    9    0
##   JFBM-54     9   14   11
##   JMBM-10    20   15   15
##   JMBM-11    12   14   16
##   JMBM-12    15    6   17
##   JMBM-14    11   10   14
##   JMBM-15    14   15   14
##   JMBM-16    14   11   15
##   JMBM-17     9    4   13
##   JMBM-18     9    6   10
##   JMBM-19    11    9    9
##   JMBM-91    13   12   15
##   JMBM-92     8    6   17
##   JMBM-93    17   20   17
##   JMBM-94     9   10   12
##   JMBM-95     9   11   20
##   NBBM-20    20   11   15
##   NBBM-21    20   19   18
##   NBBM-22    13   17   14
##   NBBM-23    14   15    5
##   NBBM-24    11   10    7
##   NBBM-25    16    3    8
##   NBBM-26    16    6   10
##   NBBM-27    18   19    9
##   NBBM-28    14    9   12
##   NBBM-30    14   12    8
##   NBBM-31    18   15   14
##   NBBM-76    24   16   17
##   NBBM-77     9   10   11
##   NBBM-78    22    6   23
##   NBBM-79    16   14   17
##   NBBM-80    18   12   25
##   PGBM-01     9   13   10
##   PGBM-02    12   19    8
##   PGBM-03    12   18   10
##   PGBM-04    11   19   14
##   PGBM-05    11   15    9
##   PGBM-06    11   23   11
##   PGBM-07    12   17   14
##   PGBM-08    12   17   19
##   PGBM-09    13   12   19
##   PGBM-108   11   18   17
##   PGBM-109   15   20   18
##   PGBM-110   17   22   27
##   SGBM-40    13   11   14
##   SGBM-41    14   14   16
##   SGBM-42    17   16   18
##   SGBM-43    12    8   19
##   SGBM-44    10   13   15
##   SGBM-45    17   18   23
##   SGBM-46    10    8   13
##   SGBM-47    12   14   12
##   SGBM-60    15    7   12
##   SGBM-61    10   20   12
##   SGBM-81    20   13   14
##   SGBM-82    13   17   17
##   SGBM-83    14   15   11
##   SGBM-84    16   10    5
##   SGBM-85     9   10   14
##   SGBM-86    16   10   17
##   SGBM-87     7   12   17
##   SGBM-88    19   17   28
##   SGBM-89    11   12   19
##   SGBM-90    20   16   20
##   STBM-58    19   19   18
##   STBM-59    18   18   28
##   TGWB-04    13   10    9
##   TGWB-15    14    7   13
##   TGWB-20    11   11   14
##   TGWB-21    16   15   17
##   TGWB-23     8   15   12
##   TGWB-24    12    9   15
##   TGWB-26    18   13    7
##   TGWB-27    11   11    8
##   TGWB-28     9   12   11
##   TGWB-29    12   14   13
##   TGWB-30    13    7   10
##   TGWB-31    13   15   10
##   TGWB-32    15   17   11
##   TGWB-34    11   15   12
##   TGWB-35    19   13   12
##   WBBM-55     3   11   15
##   WBBM-56    16   17   28
##   WBBM-57    10   18   27

Looks good, no zeroes here. So, we should have plenty of evidence (122 point estimates per year) to compare years.

Questions for Will

  • Do we want to subset to 9 species?
  • What to do about Number values >> 1
  • Can you fix the Jan 1 date value?
  • How to handle all of the NA values in distance?
  • What about angle values > 90?
  • What is detection type?
  • Are we interested in comparing years? (and do you think that later sampling in 2019 matters?)
  • Are we interested in comparing property?
  • What is BM and WB; are these groups we want to compare?
  • Are there other groups of interest?

Next steps

  • Get these questions answered.
  • Learn about n mixture models from the tutorials.
  • Test the distance functions and compare results with the n-mixture models.
  • Make a recommendation on which framework we prefer to have BCR train us on.