ZooL.— Vol. II.] LOOMIS— CALIFORNIA WATER BIRDS. 303 



As seen, high-water mark was reached in the Dark-bodied 

 Shearwater on the 23rd and 24th of September, and was 

 immediately followed by a rapid decline. The Black-vented 

 Shearwater, on the other hand, advanced in numbers until 

 its southward movements in October and November almost 

 equalled the greater of the Dark-bodied in September. 



No attempt has been made in the foregoing pages to 

 chronicle the movements of the Geese and Shore Birds 

 (except Phalaropes), for they flew at too great an elevation, 

 or gave the boat too wide a berth, to be distinctly recognized 

 in most instances. There were, nevertheless, movements 

 of considerable extent, particularly in the Shore Birds in the 

 early part of my stay. 



2. conci^usions. 



Migration Northward after Breeding Season. 



Migration from South Tevi^erate Zone. — It has long 

 been surmised that certain Petrels occurring in summer off 

 the northern coasts of North America breed in winter or 

 earl}^ spring on the oceanic islands of more southern seas. 

 It has, also, been stoutly maintained that the breeding 

 grounds of these birds would ultimately be discovered in 

 the reofions of their summer habitat. To Mr. William 

 Brewster^ and Capt. J. W. Collins^ is due the credit of 

 definitely determining by dissection that Wilson's Petrel 

 and the Greater and Dark-bodied Shearwaters do not breed 

 during their sojourn on the coast of New England and adja- 

 cent British possessions, although present in numbers after 

 the winter season. This, coupled with the previous dis- 

 covery by the Rev. A. E. Eaton^ that Kerguelen Island is 

 a breeding station of Wilson's Petrel, has given weight to 

 the theory of migration from the South Temperate Zone. 

 Corroborative, and seemingly conclusive, proof of such 

 migration is afforded by the Dark-bodied Shearwater on 

 the Pacific Ocean. The facts are as follows: — 



1 rroc. Bost. Soc. Nat. Hist., Vol. XXII, p. 404. 



- Rep. U. S. Fish Comm. for 1882, p. 314; 'Auk,' Vol. I, p. 237. 



3 Philos. Trans. Roy. Soc. London, Vol. 168, p. 133. 



