Black wheatears are small birds in Spain and Morocco. Males of the
species demonstrate an exaggerated sexual display by carrying many
heavy stones to nesting cavities. This 35--gram bird transports, on
average, 3.1 kg of stones per nesting season! Different males carry
somewhat different sized stones, prompting a study on whether larger
stones may be a signal of higher health status. Soler et
al. calculated the average stone mass (g) carried by each of 21 male
black wheatears, along with T-cell response measurements reflecting
their immune systems' strengths.
Usage
ex0727
Arguments
Format
A data frame with 21 observations on the following 2 variables.
Mass
average mass of stones carried by bird (in g)
Tcell
T-cell response measurement (in mm)
References
Soler, M., Mart<ed>n-Vivaldi, M., Mar<ed>n J. and M<U+0802C972>, A. (1999). Weight
lifting and health status in the black wheatears, Behavioral
Ecology10(3): 281--286.