THE CONDOR 
A Bi-Monthly Magazine of 
Western Ornithology 
Volume XXII March-April, 1920 Number 2 
[Issued March 22, 1920] 
THE NESTING HABITS OF THE ALASKA WREN 
By HAROLD HEATH 
WITH THREE PHOTOS 
HE GROUP of birds that among others includes the common wren of 
ae Europe and the American winter wren is widely distributed throughout 
the northern hemisphere; and considering its extensive range the amount 
of geographical variation it displays is remarkably:small. Extending from 
eastern Siberia through China, Japan and the. Kuriles, it becomes differenti- 
ated into seven closely Reel island races that constitute a connecting link 
with the North American mainland representatives. Without going into detail 
concerning the distribution of these seven races it may be said that geograph- 
ically speaking the Unalaska Island representative holds a central position with 
three races occupying distinct, isolated positions along the Aleutian chain to 
the westward; while to the eastward, within a somewhat shorter distance, we 
find the birds of the Semidi and Kodiak islands. The home of the Alaska or 
Pribilof Wren (Nannus troglodytes alascensis) is two hundred miles to the 
north. 
The birds of Unalaska Island and the races to the westward appear to be 
closely allied. Those of the Semidi Islands, on the other hand, are not as inti- 
mately related to the Unalaska form as they are to the subspecies inhabiting 
the Andreanoff archipelago two hundred miles or so to the westward of Una- 
laska. Still more remarkable is the position of the Kodiak Wren that inter- 
grades with the Pribilof type nearly seven hundred miles away. This last * 
named subspecies also shows a close resemblance to the wrens of the Andrean- 
off group, four hundred miles distant across the waters of Bering Sea. 
With these data’ in mind it is interesting to consider a statement persist- 
ently made by some of the Aleut population of St. George Island. It is an 
unquestioned fact that the number of wrens on this small, three-by-eight mile 
mass of rock undergoes very material fluctuations from time to time. In one 
year as many as forty pairs have been noted by these sharp-sighted, active ob- 
servers, and it 1s said to be equally true that during at least two summers, sep- 
arated by considerable intervals of years, not a single wren has been observed. 
1Derived from Harry C. Oberholser’s paper, “Notes on the Wrens of the Genus Nan- 
nus Billberg”’: Proc. U. S. Nat. Mus., vol. 55, 1919, pp. 223-236. 
