bird: Bird distribution data from Portugal

Description

Data from the compilation of the Portuguese Atlas of Breeding Birds.

Usage

data(bird)

Arguments

Format

A data frame with 6 columns and 25100 rows. Each row refers to one 2km by 2km square (tetrad). The columns are:

QUADRICULA: An identifier for the 10km by 10km square that this tetrad belongs to.
TET: Which tetrad the observation is from.
crestlark: Were crested lark (or possibly thekla lark!) found (1), not found (0) breading in this tetrad, or was the tetrad not visited (NA).
linnet: As crestlark, but for linnet.
x: location of tetrad (km east of an origin).
y: location of tetrad (km north of an origin).

Details

At least 6 tetrads from each 10km square were visited, to establish whether each species was breeding there, or not. Each Tetrad was visited twice for one hour each visit. These data are not definitive: at time of writing the fieldwork was not quite complete.

The data were kindly supplied by Jose Pedro Granadeiro.

References

Wood, S.N. (2006, 2017) Generalized Additive Models: An Introduction with R

Examples

Run this code

# NOT RUN {
  data(bird)
  species <- "crestlark"
  op<-par(bg="white",mfrow=c(1,1),mar=c(5,5,1,1))
  ind <- bird[[species]]==0&!is.na(bird[[species]])
  plot(bird$y[ind]/1000,1000-bird$x[ind]/1000,pch=19,cex=.3,col="white",
     ylab="km west",xlab="km north",cex.lab=1.4,cex.axis=1.3,type="n")
  polygon(c(4000,4700,4700,4000),c(250,250,600,600),col="grey",border="black")
  points(bird$y[ind]/1000,1000-bird$x[ind]/1000,pch=19,cex=.3,col="white")
  ind <- bird[[species]]==1&!is.na(bird[[species]])
  with(bird,points(y[ind]/1000,1000-x[ind]/1000,pch=19,cex=.3))
  par(op)
# }

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