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
SpeciesnMeanStandard Deviation
Hedge Sparrow1423.121.07
Meadow Pipet 4522.300.92
Pied Wagtail 1522.901.07
Robin 1622.580.68
Tree Pipet 1523.090.90
Wren 1521.130.74

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                     


Data and Story Library (

USGS Patuxent Wildlife Research Center (

Last modified: March 20, 2001

Bret Larget,