R: Orientation of juvenile barn swallows

swallows {circular} | R Documentation

## 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

### 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))

[Package circular version 0.4-93 Index]