swallows: Orientation of juvenile barn swallows

In circular: Circular Statistics

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

Source

Giunchi, D., and Baldaccini N. E. (2004) Orientation of juvenile barn swallows (Hirundo rustica) tested in Emlen funnels during autumn migration. Behav. Ecol. Sociobiol. (56):124-131.

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))

Example output

Attaching package: ‘circular’

The following objects are masked from ‘package:stats’:

    sd, var

circular documentation built on May 2, 2019, 4:42 p.m.