1913] Swarth: Geese of California 7 



characters of this form, as distinguished from canadensis, are: (1) 

 extremely dark coloration; (2) slightly smaller size, that is. the max- 

 imum of occidentalis is below the largest canadensis ; (3) proportion- 

 ally longer tarsus. 



Of six specimens of occidentalis, four have eighteen reetrices each, 

 one has sixteen and one fourteen. 



The greater size of occidentalis serves to distinguish it from hutch- 

 insi. Although occasional specimens of the latter are as darkly colored 

 as occidentalis, all such specimens examined are of small size, evidently 

 intergracles between Itutchinsi and the dark-colored minima. 



Although in general tone of coloration occidentalis approaches 

 minima, the difference in size between the two is in most cases so 

 great as to render improbable any confusion of the races. This differ- 

 ence is to some extent bridged by our specimens from Prince William 

 Sound, which, as mentioned above, are distinctly smaller and darker 

 than southern Alaska examples of occidentalis. The region they 

 inhabit is closer to the range of minima, and it is fair to believe that 

 these specimens illustrate a step in the gradual transition between 

 the two forms, which probably occurs. They are, however, distinctly 

 closer to typical occidentalis than to minima. 



The type specimen of occidentalis, in its small size, reddish colora- 

 tion, and suggestions of white collar and black throat line, appears to 

 approach minima even more closely than do the Prince William Sound 

 specimens. The probability suggests itself that this bird, of inter- 

 mediate character, is from some point between the habitats of typical 

 occidentalis and minima, and a winter visitant only, at the point of 

 capture. Port Townsend, Washington. This implies a mode of migra- 

 tion that is paralleled by that of other species of birds of the north- 

 west coast region, such as with the fox sparrows (Passer ella iliaca 

 subspp.) and the hermit thrushes (Hylocichla guttata subspp.). That 

 is. the individuals inhabiting the northernmost part of the region (as 

 at Prince William Sound) pass over the Sitkan district immediately to 

 the southward, and spend the winter in the southernmost parts of 

 the humid region, while the birds of the Sitkan district either remain 

 there throughout the year, or else move but a short distance to the 

 southward. It is the northernmost individuals that perform the 

 longest flights. 



