TENTH ANNUAL REPORT. 161 



Consideration of the evolution of color in this group reveals 

 several perplexing- problems. Like other arctic birds, such as the 

 gyrfalcon, snowy owl, ivory gull, and ptarmigan, all the northern 

 swans are white in their adult plumage ; but if this be a protective 

 character it requires a special definition. Feeding on organic mat- 

 ter, which they glean from shallow water, any question of aggres- 

 sive coloration is_, of course, absurd. Unlike the ptarmigan, 

 swans are birds of strong migratory habits, and although breed- 

 ing in the far north, yet their nests are not among ice and snow, 

 but in the grass and reeds near water. So the white color would 

 seem to be, instead of a protection, an actual adventisement of 

 the bird's whereabouts. These great birds are well capable of 

 defending themselves against any foe of moderate size, striking 

 with the hard bend of the wings, blows of remarkable force and 

 precision. When we consider, too, the usual open character of the 

 country in which these birds spend their lives — open arctic tun- 

 dras in the north, larger bays along the sea-shore when in more 

 southern latitudes — and the unusually keen senses of sight and 

 hearing with which these birds are endowed, we realize that the 

 white color of the plumage may have come about by the birds' 

 very immunity from danger. 



Of course in this connection we must ignore man. Such long 

 established and slowly evolved features as the colors of wild birds 

 have for their causes, conditions which long antedate the com- 

 paratively recent and abrupt dominion of man. When a great 

 swan, swinging across the sky in all his glory of wild strength, is 

 smitten by a shower of lead from a hidden blind ; or when, ren- 

 dered helpless by the simultaneous moult of all their flight feath- 

 ers, a whole flock is surrounded by nets, and old and young to- 

 gether slaughtered by the barbarous Eskimo, it is because these 

 birds are unable to cope with such sources of danger, introduced 

 into their environment w^ithin, comparatively speaking, but a few 

 years. 



Although the swans themselves are so conspicuous when on the 

 nest, yet, when the sitting bird has left, the nest itself is very 

 difficult to discover. It is a mere pile of rubbish, thrown care- 

 lessly together, and before leaving, the parent bird always care- 

 fully draws the lining of the nest completely over the eggs, so 

 that they are well hidden from prying eyes. Under these con- 

 ditions the conspicuous color of the birds and the great com- 

 motion wdiich they necessarily make in getting under headway 

 would all tend to distract attention from the exact position of the 

 nest if the parents should retreat on the approach of an enemy. 



