The Pink-footed Shearwater 



THOSE who are only slightly familiar with the phenomena of bird 

 migration often wonder why the process is not reversed; i. e., why the 

 Southern Hemisphere does not send its birds north to "winter" (in our 

 summer). The situation is a complicated one, and we may not press for 

 the solution here, save as it affects one group. So far as the Tubinares 

 are concerned, the answer is a clear one: It does. Since the Southern 

 Hemisphere is also the aqueous hemisphere, it is natural that these 

 strictly pelagic species, comprising the "ocean wanderers," should have 

 their center of abundance there. But Antarctica in her winter is even 

 more inhospitable than Arctica in ours; hence, the pronounced tendency of 

 tube-nosed birds to wander north at apogee. This tendency has become 

 a fixed habit of migration in the case of the Puffinidce, the Shearwaters. 

 Many of those reared at high southern latitudes fall back upon the north 

 temperate zone for their winter sustenance, and even some reared in the 

 northern tropics, like our own P. opisthomelas , or P. audiiboni of the 

 Bahamas, range further north for the bulk of the year. 



Our knowledge of such movements is largely supplemented by the 

 flotsam of dead bodies cast up on our beaches. Occasionally these floaters 

 are so numerous as to arrest attention; as in the summer of 1908, when 

 Mr. J. H. Bowles discovered that many species of sea-birds off the coast 

 of Washington were suffering from an enteric parasite which notably 

 depleted their ranks. But the ordinary movements of the Shearwaters, 

 conducted as they are upon so vast a scale, are attended with a loss of life 

 from natural causes of accident and decrepitude, which line the beaches 



Taken near Santa Barbara 



MOSTLY DARK-BODIED, 



SHEARWATERS AT REST Photo by the Author 



BUT THE LIGHT BIRDS ARE SURMISED TO BE PINK-FOOTS 



1997 



