102 University of California Publications in Zoology. [Vol. 7 



9473) had laid part of its set, and contained a partly formed 

 egg that would have been laid in a day or two, and the other, 

 shot on June 23 (no. 9475) was evidently incubating. The 

 males were in full song, and it was the familiar " witch-a-ree " 

 note that first drew my attention to the presence of these birds, 

 so unexpected in this region. They were shy and retiring, the 

 grass they were in was waist high and higher, and altogether it 

 was no easy matter to see them in the first place, or to find a bird 

 after it was shot. The species was subsequently met with only on 

 the Taku Eiver, where a few were seen on September 4, and 

 again on September 9, none being observed after the latter date. 

 Ten specimens were secured, five adult males and two adult 

 females from the Chickamin River (nos. 9472-9478), and two 

 immature males and an immature female from the Taku River 

 (nos. 9479-9481), the latter in complete first winter plumage. 

 They are, as far as I can see, quite indistinguishable from a ^eries 

 of breeding birds from Humboldt County, Nevada, which may 

 be considered as typical of occidentalis; but even aside from 

 the appearance of the birds, the manner of their occurrence 

 alone would incline one to place their affinities with the form of 

 the interior, rather than with arizela of the more southern coast 

 region. It will be noticed that the two places where yellow- 

 throats were found were along the margins of large rivers which 

 pierce the mountains paralleling the coast, and form direct and 

 favorable passes from the interior; it is my belief that the birds 

 reached the coast by following down these streams. If the form 

 found in southern British Columbia (arizela) reached Alaska at 

 all it would be by way of the coast, where it might be expected to 

 occur at all suitable points. Besides the places where we found 

 yellowthroats, we worked at several mainland points apparently 

 admirably adapted to their needs, Boca de Quadra, Thomas Bay, 

 and Port Snettisham, but in these localities we failed to find 

 them. At none of these points, however, is there any such high- 

 way to the country beyond the mountains, the streams either 

 arising from the glaciers, or if they go back into the mountains 

 for any distance, passing through rough, precipitous country, 

 utterly unsuited to the birds ' requirements. Hasselborg ascended 

 the Chickamin River some twenty-five miles, finding meadow 



