National Geographic : 1956 Jul
Birds Swarm About + the Author at Feeding Time Mr. Ivor shelters nearly 100 birds of more than 25 species in his observatory. During nesting periods the songsters feed in near-by woods, but they always return. Here a cedar waxwing rides the naturalist's shoulder. An other waxwing and an oriole perch on his hand. A bluebird clings to his sleeve. W. Robert Moore. National Geographic Staff 117 The crow and some magpies, however, are notable exceptions. My crow not only enjoys having its head, back, and wings stroked, but crouches on an anthill, closes its eyes, and seems to derive much pleasure from having the ants crawl over its plumage. But it does not ant in the accepted sense. Yet the European magpie, a rela tive of the crow, has been seen to ant like the smaller passerines. Several persons in the United States have advanced the theory that anting may be a form of dressing the plumage. Mrs. Whitaker has treated feathers by rubbing ants on them. Her orchard oriole will grasp one of these treated feathers with its foot, probe between the barbs, and run its tongue there and on the flat surface of the web. The oriole's throat muscles move as in swallowing, and the bird obviously is attracted by the odor or taste of some ant substances. I have dampened earth particles with formic and citric acids, but my birds do not react to them. There are many other aspects to this odd ornithological puzzle. While many of the passerine birds ant, others apparently do not. One wonders why their behaviors should differ. The catbird and brown thrasher, for ex ample, are considered to be related. Both are insectivorous, they nest in somewhat simi lar situations, and they live during the sum mer in a similar environment. Here in my songbird observatories both have access to the same earth containing ants. My catbirds ant, but my brown thrashers do not. Anatomically, the American robin and blue bird are both thrushes. My bluebirds mingle with my robins but do not join in the anting (pages 118, 119). If the robins and catbirds ant against their wing and tail feathers to rid themselves of some irritating substance, as Poulsen states, why does not the same sub stance irritate the bluebird and brown thrasher? Puzzle Remains Unsolved To me, it seems remarkable that the blue bird, thrasher, and many other species do not need to ant for any of the suggested pur poses, while the catbird, robin, and many others do. It is equally puzzling that some birds ant frequently and others do so only rarely. In nearly 18 years of observation, for example, I have seen the evening grosbeak and the cedar waxwing ant only once. In many ways it seems that anting is a primal form of behavior, lost by some birds but retained by others. We must, in my opinion, continue to seek the "definitive solution to one of the outstand ing puzzles of ornithology."