**Xi'an's Og » R**, and kindly contributed to R-bloggers)

**I**n *Tangente n⁰42*, there was a [Latter, 1902] dataset about the size of cuckoo eggs against the species (goldcrest and warbler) which built the nest. *(The whole dataset from Latter is analysed in Maindonald and Braun’s Data Analysis and Graphics Using R, with a degree of caution about how trustworthy this data is…)* This is an old reference, but the Wikipedia entry on cuckoos reproduces this finding: “Female parasitic cuckoos specialize and lay eggs that closely resemble the eggs of their chosen host.” Even if Latter’s data is correct and the difference significant, there may be a good explanation for the variability shown in the boxplot below: I would think that it is more likely that subspecies of cuckoos evolved to fit the eggs of different species of birds, rather than a generic cuckoo producing an egg that fits the size of the eggs in the nest it has just landed in!

cuckoo=list(gold=c(19.8,22.1,21.5,20.9,22.0,21.0,22.3, 21.0,20.3,20.9,22.0,22.0,20.8,21.2,21.0), warbl=c(22.0,23.9,20.9,23.8,25.0,24.0,23.8,21.7, 22.8,23.1,23.5,23.0,23.0,23.1)) boxplot(cuckoo,col=c("gold","wheat"),names=c("goldcrest","warbler"))

(The journal *Tangente n⁰42* plots instead a rather inaccurate histogram to deduce that the two samples have different distributions…)

Filed under: Books, R, Statistics Tagged: brood parasitism, cuckoo, goldcrest, testing of hypotheses, warbler

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