AHMbook (version 0.2.5)

crossbillAHM: Data from the Swiss Breeding Bird Survey MHB for European Crossbill from 2001 to 2012

Description

The Swiss breeding bird survey ("Monitoring H<U+00E4>ufige Brutv<U+00F6>gel" MHB) has monitored the populations of approximately 150 common species since 1999. The MHB sample consists of 267 1-km squares that are laid out as a grid across Switzerland. Fieldwork is conducted by about 200 skilled birdwatchers annually, most of them volunteers. Avian populations are monitored using a simplified territory mapping protocol (also called spot-mapping West of the Atlantic), where each square is surveyed up to three times during the breeding season (only twice above the tree line around 2000 m elevation). Surveys are conducted along a transect that does not change over the years and is 4-6 kms in length on average.

The data frame crossbillAHM has the data for European Crossbill (Loxia curvirostra) from 2001 to 2012.

A variant of this data set for 1999 to 2007 only is included in package unmarked.

Usage

data("crossbillAHM")

Format

crossbillAHM is a data frame with 267 rows and 77 columns:

coordx, coordy

the x and y coordinates of the center of the quadrat; the coordinate reference system intentionally not specified.

elev

the mean elevation of the quadrat, m.

forest

percentage forest cover

nsurveys

the number of replicate surveys planned in the quadrat; above the tree-line 2, otherwise 3.

det011 to det123

1 if the species was detected in the quadrat, 0 otherwise; NA if the corresponding survey was not carried out; the first 2 digits indicate the year and the 3rd digit the survey.

date011 to date123

Julian date of the survey, 1 = 1st January; the first 2 digits indicate the year and the 3rd digit the survey; NA if the corresponding survey was not carried out.

References

K<U+00E9>ry, M & Royle, J.A. (2021) Applied Hierarchical Modeling in Ecology AHM2 - 4.

Examples

# NOT RUN {
data(crossbillAHM)
str(crossbillAHM)

# Extract data as site x survey x year arrays
ytmp <- as.matrix(crossbillAHM[, 6:41]) # matrix of detections
y <- array(ytmp, c(nrow(ytmp), 3, ncol(ytmp)/3))
datetmp <- as.matrix(crossbillAHM[, 42:77])  # matrix of Julian dates
date <- array(datetmp, c(nrow(datetmp), 3, ncol(datetmp)/3))

# }