222 NORTH AMERICAN FAUNA 61, FISH AND WILDLIFE SERVICE 



ing Sea fall into another group or species. Some such course was 

 suggested by Swarth (1931), who wished to regard the "North 

 American, the Bering Sea, and the Old World group, each as a 

 separate species." 



There has not been opportunity to review the Old World wrens, 

 and because they have generally been placed in the species 

 troglodytes, that name is the most convenient to use for the 

 Aleutian group until the relationships with the Old World group 

 can be determined. 



The Aleutian winter wrens are a difficult group to identify be- 

 cause their plumages vary so greatly with wear and we do not 

 always have comparable plumages for study. Giving these facts 

 their due weight, we cannot speak with too much assurance in 

 some cases, nor can we rely too much on island isolation to pro- 

 duce new characters. 



The winter wren is one of the few small land birds found 

 commonly throughout the Alaska Peninsula-Aleutian district. 

 This is a bird of the rocky shoreline, nesting in rock crevices. 

 It was not found far inland; in fact, it apparently prefers the 

 vicinity of the sea, and it finds its favorite habitat on islands. 



On Amchitka Island, July 11, 1937, I found a family of young 

 winter wrens on the beach, and, a few days later, I found a nest 

 with eggs. This nest had been placed in the timber structure of 

 an old barabara. On July 17, these eggs hatched. They were 

 probably a second laying. 



Troglodytes troglodytes heller] 



This is the wren of the Kodiak-Afognak Islands. It has not 

 been determined if it also occurs on the adjacent parts of Alaska 

 Peninsula. 



This winter wren is quite similar to pacificus in coloration, 

 when comparable plumages are used. The bill, however, is slightly 

 longer. Measurements are as follows : 



helleri (9 males) 10 to 11.5 mm.; average, 11.1 mm. 



pacificus (5 males, chiefly from Alaska) .... 10 to 11 mm.; average, 10.4 mm. 



Troglodytes troglodytes semidiensis 



This form is confined to the Semidi Islands. According to 

 Brooks (1915), it is "similar to N. alascensis, but less rufescent, 

 especially above; bill longer." He gave the length of culmen of 

 two males, including the type, as 16 mm. This is in contrast with 

 the average of 11.1 mm. for helleri. 



