320 BULLETIN OF THE 



prising divisionist to give them a distinctive name, they are interesting 

 as indicating a rufous western race, corresponding with the Accipiter 

 mexicayius form of the A. Cooperi, the Falco nigripes form of the F pere- 

 grinus, the Archibuteo ferrugineus form of the A. lagopus, and the west- 

 ern rufous forms of Jiuleo borealis and Circus hudsonius.* 



Although the Accipiter fuscus has always been regarded as closely re- 

 lated to the Accipiter nisus of the Old World, they have, with one or two 

 exceptions,! been regarded by all authors as specifically distinct. The 

 only distinctive difference between them, however, has been properly re- 

 garded as a slight difference in color, which difference is merely one of 

 tint, the style of coloration being precisely the same in both. In the 

 Museum of Comparative Zoology are several specimens of A. nisus from 

 Germany and Switzerland, which represent both the adult and the young. 

 The brown transverse markings on the lower plumage of the mature A. 

 nisus are rather darker and broader than in most New England specimens 

 of .i. fuscus ; but they still more closely resemble average New England 

 specimens than the latter do any specimens of A. fuscus I have seen from 

 the western parts of the United States. The western form of A. fuscus, 

 as already stated, is brighter colored or more rufous than the eastern, 

 while the eastern differs similarly from the European, the latter being 

 much duller colored than the eastern form of A. fuscus. So closely, how- 

 ever, does one of the immature examples of A. nisus resemble several of 

 the immature New England specimens of A. fuscus, that, if their origin 

 was unknown, few ornithologists would probably consider them as other- 

 wise than specifically identical ; especially if placed in a large series com- 

 posed of both eastern and western specimens of the A. fuscus. As I have 

 previously remarked, the transverse markings on the lower plumage in the 

 adult stage are broader and more regular and distinct in A. nisus than in 

 A. fuscus. This, it may be added, is also the only difference observable be- 

 tween A. palumbarius and A. atricapillus. Such a coincidence of parallel 

 differences between Accipiter nisus and Accipiter fuscus, and between 

 Astur palumbarius and A. atricapillus, is a point of much interest to any 



* For further remarks concerning the rufous western races of several of these species 

 see the following pages. 



t Prince Max zu Wied, in his " Beitrage zur Naturgeschichte von Brasilien," referred 

 a hawk, probably of this species, of which he obtained a single immature mule in Fa-t- 

 ern Brazil, to the Falco nisus Linn. Respecting this species lie observes: " Der Vogel 



dieser Beschreibung scheint von dem europaischen Sperbernicht abzuweichen 



t mir selbst in Braslien nicht vorgekommen, allein Freireifs hat mir 

 ein Exemplar davon mitgetheilt, welches in derGegendvon Camamu, sudlich von Bahia, 

 geschossen wurde. So viel ich von diesem einzigen Individuo urtheilan kann, so scheint 

 <■- 1 lentisch mit dem europaichen Xisus zu seyn; denn sowohl seme Verhaltnisse als sein 

 Gefieder stimmen vollkommen uberein." Vol. Ill, pp. 112, 114. 



