CALIFORNIA WATER BIRDS. 185 



It has long been held that the individuals of a species 

 found during the summer months south of the breeding 

 range, but not breeding, are actual summer residents, 

 having failed to migrate northward, or at least failed to 

 complete the migration, owing to barrenness or some ac- 

 cidental cause. Such cause might possibly exist in tem- 

 porary sickness or wounds, or the way ma}^ have been 

 lost, particularly if the loiterers were young birds. This 

 view is not incompatible with the fact of early southward 

 migration. Such stragglers may occur, and when the 

 tide of migration sets southward they ma}^ join the ranks 

 of the early migrants of other species. The Fulmar 

 alluded to above may be an example. It may not have 

 reached the breeding habitat, and have come from a 

 locality to the southward of it, joining the Shearwaters 

 as they passed by or falling in with them on the way down 

 the coast. The fluctuations occurring in the Scoters may 

 have been occasioned by the early departure southward 

 of June birds and the arrival of others a little later from 

 further north — such local movement being in advance of 

 the migration from the boreal breeding grounds. While 

 fully recognizing physical debility and accident as factors 

 in this question, too gre.at stress must not be laid upon 

 them, for ample allowance must be made for late north- 

 bound migrants and early southbound migrants, as the 

 two migratory movements nearly or quite bridge over the 

 interval of summer. Movements of Black Turnstones 

 from the southern frontier of their breeding range, if they 

 consumed a fortnight and were as early as those of the 

 California Murres, would reach the vicinity of Monterey 

 about the ist of July. It should be added that the young 

 of this Turnstone are able to take wing in July and leave 

 the flats of the Lower Yukon for the sea-coast (Nelson, 

 Rep. Nat. Hist. Coll. Alaska, p. 130). 



