SEASONAL LIFE 



have deeply incised margins filled in with white, the latter dis- 

 appears, leaving a dull rusty brown feather with a serrated edge 

 as is shown in 111. i8. But Mr. Beebe, 

 of the New York Zoological Gardens, 

 made some experiments which 

 seem to show, on the other hand, 

 that strong light, in itself, may 

 have the effect of intensifying colour. 

 " I transferred," he says, " a male 

 Purple Finch, which had for several 

 years moulted yellow, from a dark 

 cage to one which was exposed to 

 bright sunlight, and in one moult 

 the bird assumed his original normal 

 colour". But this may have been due 

 rather to the more vigoro^]s health 

 of the bird, following on the improved 

 conditions of captivity. Loss of 

 colour certainly cannot invariably be 

 set down to the action of light, for it 

 is well known that many brilliantly 

 coloured birds become more or less 

 pallid in captivity. This is especi- 

 ally noticeable in the case of Flamin- 

 goes which lose their wonderful rose 

 colour and become almost white in 

 Zoological Gardens. 



The curiously bleached appear- 

 ance of desert forms may possibly 

 prove to be the result of intense light, 

 or more probably light and a dry 

 atmosphere accompanied by a high 



temperature, since the most pallid forms appear always to occur 

 where the temperature is very high, and the air free from mois- 

 ture. And it is well known that a sandy desert heats the atmo- 

 sphere above it much more than a fertile tract or a watery expanse. 

 As to the bleaching and the opposite effect of intensification, Mr. 

 J. S. Whitaker, in describing the various races of crested Larks 

 met with in Tunisia, remarks : " In their coloration and mark- 

 ing they vary according to the particular district inhabited ; thus, 

 6 



III. i8. — A Wing Feather of 

 A Curlew Showing the 

 Initial Stages in the Dis- 

 integration OF THE White 

 Parts : and a Portion of 

 THE Quill Feather of a 

 Gull Showing the same 

 Process 



Note the imperfect tip of 

 the feather, and the worn inner 

 edge of the white portion, and 

 contrast w th the unworn black 

 area. 



