Evidence Afforded by Captive Birds. 57



well as various species of more ordinary waterfowl; but the in¬

clement season seemed to affect even these birds, for I never knew

so many unfertile egg's laid.


An otter, passing through my enclosure one night in March,

killed two valuable birds, a Versicolor and a Cinnamon Teal, both

drakes. It is not the first time that this has happened ; one spring

an otter broke up five pairs of ducks of different species in one

“ raid.” They are hard to keep out, and not the least provoking part

of it is that it is pure mischief that prompts the act, for the otter

seldom eats the birds, but contents himself with crushing their bodies

with his powerful jaws, apparently seizing them from below, while

swimming under water.



EVIDENCE AFFORDED BY CAPTIVE

BIRDS.


By Dr. Arthur G. Butler.


In an article by W. L. McAfee, published in the Academy of

Natural Sciences of Philadelphia for June, 1912, entitled “ The

experimental method of testing the efficiency of warning and cryptic

coloration in protecting Animals from enemies ” the author argues

that the evidence brought forward in support of the theory of

protective coloration in animals by the students of animals in

captivity is altogether unsound, inasmuch as it has been proved by a

wholesale examination of the stomachs of wild animals that their

natural tastes differ considerably from those of captive animals : he

says with regard to information on the natural food habits of birds

contained in the United States Biological Survey “ They comprise

detailed informations of the contents of more than 48,000 bird

stomachs representing all families of birds and collected in hundreds

of localities in the United States at all seasons. The United States

has a goodly representation of butterflies, yet only five of these

48,000 stomachs contained remains of Rhopalocera. It is hoped

this will be more satisfactory to the selectionists than the “ negative

evidence ” they are accustomed to cite with contempt.”



