Math 225

Introduction to Biostatistics

Cuckoo Birds

Cuckoo birds have a behavior in which they lay their eggs in other birds nests. The other birds then raise and care for the newly hatched cuckoos. Cuckoos return year after year to the same territory and lay their eggs in the nests of a particular host species. Further, cuckoos appear to mate only within their territory. Therefore, geographical sub-species are developed, each with a dominant foster-parent species.

A general question is, are the eggs of the different sub-species distinct so that they are adapted to a particular foster-parent species?

Specifically, we can ask, are the mean lengths of the cuckoo eggs the same in the different sub-species?

Cuckoo Egg Length Data.

Summary Statistics

Summary Data of Length of Cuckoo Bird Eggs by Foster-Parent Species
Species	n	Mean	Standard Deviation
Hedge Sparrow	14	23.12	1.07
Meadow Pipet	45	22.30	0.92
Pied Wagtail	15	22.90	1.07
Robin	16	22.58	0.68
Tree Pipet	15	23.09	0.90
Wren	15	21.13	0.74

Anova Table

             Df Sum of Sq Mean Sq F Value        Pr(F) 
birdSpecies   5  42.93965 8.58793 10.3877 3.152104e-08
  Residuals 114  94.24835 0.82674

References

Data and Story Library (http://stat.cmu.edu/DASL/).

USGS Patuxent Wildlife Research Center (http://www.mbr-pwrc.usgs.gov/).

Last modified: March 20, 2001

Bret Larget, larget@mathcs.duq.edu