BIRDS OF THE PAST — WETMORE 387 



To return to our Pleistocene avifauna, we find several deposits that 

 have yielded abundant bird remains. The earliest known of these 

 important beds was that of Fossil or Christmas Lake, in the arid 

 section of Oregon, where deposits containing hundreds of bones of 

 birds have been explored. These, studied first by Shufeldt and later 

 by Miller, have given a varied list of birds, mainly aquatic, of which 

 a number have been described as species distinct from those existing 

 to-day, and many have been identified as identical with living forms. 

 Dr. O. P. Hay considers the age as first interglacial. Of the more 

 than 20 peculiar species only one, Palaeotetrix gilUi, is now held to 

 be generically distinct from living birds. The flamingo, Phoeni- 

 copterus copel, is the most unusual species in the assemblage, as any 

 of the other genera might be expected in this area to-day. It may 

 be remarked that the flamingo is no criterion for particularly warm 

 climate at the time mentioned, since a somewhat similar species of 

 flamingo now ranges and nests in South America through Patagonia 

 where the summer weather is often cold and inclement. 



The deposits of bird bones from this Oregon locality are found 

 in an old lake bed that from modern conditions might be supposed 

 to be similar to the small alkaline lakes now common in this area. 

 If this is true it is possible that the great abundance of bird remains 

 is indicative of a condition in the Pleistocene similar to one that has 

 destroyed hundreds of thousands of waterfowl in the western part 

 of the United States in recent years. The malady to which I allude, 

 the so-called " duck sickness," has been especially prevalent in the 

 past 20 years in the deltas of streams flowing into Great Salt Lake in 

 Utah, but is known in alkaline lakes in a number of other sections, 

 including the Malheur region of Oregon. Briefly, it appears that 

 birds, principally ducks and other aquatic species, become afl^ected 

 by excessive concentrations of alkalis in the waters in Avhicli they 

 feed, and, unless they can have immediate access to fresh water, they 

 become paralyzed and die. Aquatic birds of various kinds have been 

 afl'ected and the number of individuals known to have been thus 

 killed in the last 20 years has been tremendous, running literally into 

 the millions. The possibility of the accumulation of extensive de- 

 posits of bones of birds that may be preserved as fossils under these 

 conditions is easily evident. 



The most famous deposit of Pleistocene vertebrate remains in the 

 New World is that of Rancho La Brea on the Californian coastal 

 plain only a few miles from the business center of the city of Los 

 Angeles. Here outpourings of asphalt from the depths of the earth 

 have been exposed in such a way that they have served to entrap 

 animals which were held in sticky embrace until death came to them, 

 and then, when decay had released their skeletons, to entomb the bones 

 in a bed of tar where many have been preserved in perfect condition. 



