3IO CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



halting upon the water, the Northern Phalarope ^ being an 

 example in the early migrations and the Surf Scoter in the 

 later. It was also found that the first representatives of a 

 species in summer, in transitu, were either wholly old birds 

 or old ones sparingly accompanied by birds-of-the-year, as 

 in the Marbled Murrelet July 30, 31, 1894.^ Under such 

 circumstances it is not surprising that the young weak- 

 winged travelers drop out from migrants passing by offshore 

 and occur at the kelp and other places of refuge sooner than 

 the adults, giving the appearance of migration of the young 

 in advance of the old.^ Not improbably the first adults are 

 largely birds that have failed in reproduction,* as in the 

 Murres at South Farallon.^ Otherwise the young would be 

 left behind, so far as their own kind is concerned, and com- 

 pelled to seek their way alone, or depend upon such for- 

 tuitous guidance as might be afforded by belated old birds. 

 It is true they might associate themselves with other species 

 and be guided by them, provided there was no parting of 

 ways.^ Still the young of those last to go would be without 

 direction if unaccompanied by their parents. 



Older birds, however, occurred at Monterey in the closing 

 as well as the opening movements of a species, for example 

 in Western and Heermann's Gulls November 4, 5, 12. This 

 seems to be the case also in the spring migrations, for birds 

 in high plumage were well represented in May, 1897, the 

 large flocks of Bonaparte's Gulls and Northern Phalaropes 

 during the middle of the month having a liberal percentage. 



1 ' Auk,' Vol. XI, pp. 27, 28; Calif. W. B. No. I, pp. igo, 195, 196, 201, 204, etc. See also 

 ' Calendar,' Sept. 18. 



2 Calif. W. B. No. I, pp. 191, 192, also 194. 



3 The way is not open in early spring for an extensive passing over, obstructions of 

 weather preventing it. Consequently the vanguard is more readily seen when territory 

 is invaded by the advancing host of migrants. I^ater in the season the conditions are 

 more favorable for protracted migration and the occurrence of loitering young birds. 



* Possibly in some instances they are males or females that have left the young to the 

 care of the opposite sex. 



s Calif. W. B. No. Ill, pp. 357, 358. 



•i Manifestly such guides, even if part of a " straggling array, often hundreds of miles 

 in length," must take the young directly to the winter habitat of the species, for fixity 

 of destination in the young is as necessary as migration itself. Without it there could 

 be no uniformity of dispersal, for the young become the old of following years. If there 

 was any divergence of route, they would be thrown upon their own resources, old birds 

 of the same species being wanting, and forced to decide which way to go. This being 

 the case, the difficulty is merely shifted from the beginning to the latter part of the mi- 

 gration, the young still having to find their way to a terra incognita. 



