circular (version 0.5-1)

swallows: Orientation of juvenile barn swallows

Description

The _swallows_ dataset has 114 rows and 2 columns. The observations are the headings of juvenile barn swallows (_Hirundo rustica_) tested in orientation cages (Emlen funnels) during autumn migration under simulated overcast conditions.

Usage

data(swallows)

Format

A data frame with 114 observations on the following 2 variables.

treatment

a factor with levels control (control group: local magnetic field) and shifted (shifted magnetic field, magnetic North = geographical West)

heading

a numeric vector: modal heading of each bird

Examples

data(swallows)

swallows <- split(swallows$heading, swallows$treatment)
swallows <- lapply(swallows, function(x) circular(x, units='degrees', template='geographics'))

plot(swallows[[1]])
points(swallows[[2]], col=2)
legend('topright', legend=c('control', 'shifted'), pch=c(19,19), col=c(1,2))