BIRD FLAVORS [Ref]
Particularly in the study of insects it has been shown that bright or contrasting and conspicuous colors tend to be associated with ill-flavor in the animals that wear them, while insects with a good flavor tend to be so colored that they are difficult to see. The first is a warning coloration—advertising to a predator that he will not enjoy eating this insect and better leave it alone; the other is concealing color, its function apparently to keep predators from finding their prey. The tasters in the experiments that have been used to work out the above generalizations were usually birds, but, as checks, a variety of other animals were used, and the magpie moth (Abraxas grossulariata), for instance, was found to be distasteful to certain spiders, frogs, lizards, various birds, a bat, and finally "the late Dr. Hans Gadow (one of the leading ornithologists of his day), who made a practice of sampling caterpillars, remarked on trying an A. grossulariata that it was quite one of the worst he had ever eaten!" Apparently ideas in taste are similar throughout large sections of the predatory animal world. Reversing the usual role, and using insects (hornets) as tasters of bird flesh, the celebrated British naturalist, Dr. H. B. Cott, has recently studied the question of the palatability in birds and their coloration. Naturally Dr. Cott, with his customary thoroughness, compared hornets as tasters with other animals, including cats and men, and found a surprisingly close agreement in the results.
The experimental procedure was to expose the flesh of two different birds (without feathers) at the same time, and see which the wasps ate first. Thus a graded series was built up of the 38 species of birds tested, with a palatability rating of from 1 to 38. The wryneck and the crested lark stood at the top of the list, and the pied kingfisher and the white-rumped black chat, as the least palatable, at the bottom with Numbers 37 and 38.
Then, surveying the coloration of the birds, and their habits, Dr. Cott made the important correlation that in general the birds whose flesh was most edible were protectively colored, and those whose flesh was least palatable tended to be conspicuous in color and behavior!
To relate it to the theory of evolution Cott concludes that selective pressure by predators seems to have forced vulnerable species along two divergent lines of specialization: leading in those which are relatively palatable toward concealment, and in those which are relatively distasteful toward advertisement.
HOW MANY FEATHERS HAS A BIRD? [Ref]
The question as to the number of feathers on a bird seems a simple one without complication. Dr. Wetmore, the well-known ornithologist who was secretary of the Smithsonian Institute, has given us some data. The number varies with the species, of course: the smallest bird, a hummingbird from Cuba, had the fewest, 940 feathers; larger birds had more, the robin 2587, and the mourning dove 2635 feathers. A glaucous-winged gull had 6540; a mallard 11,903 feathers; a Plymouth Rock chicken was said to have 8325 feathers; and a later investigator reported 25,216 feathers on a swan.
But as one thinks of it, more questions arise, as in any investigation. The answer to one question poses two more. The first question is, do not the birds in winter need a wanner plumage to keep out the cold than they do in summer, when it is warm? Do they have more feathers then? This was definitely true in the case of the goldfinch: a bird in summer dress had only 1439 feathers, while one in winter plumage had 2368 feathers, obviously an adaptation for cold weather.