214 BULLETIN 195, UNITED STATES NATIONAL MUSEUM 



nesting sites, but Dr. Sutton (1930) found no evidence that the house 

 wren molested the nests of the Carolina wren, and concluded that these 

 two species could live together with less friction than the house wren 

 and Bewick's wren. 



Dr. Friedmann (1929) gives several instances in which this wren 

 was victimized by the cowbird ; and Mrs. Nice (1931) lists 4 nests out of 

 16 that were so parasitized in Oklahoma. 



Winter. — The Carolina wren is preferably a sedentary species; it 

 likes to remain where it has found a suitable home throughout the 

 year. This trait has somewhat limited the northward extension of 

 its permanent range. Migratory birds may extend their range north- 

 ward in spring and summer and retire southward before winter ; they 

 thus escape the rigors of a northern winter ; but this wren does not 

 seem to take this wise precaution. During summers and mild winters 

 they increase in numbers throughout the middle and northern States, 

 as illustrated by Dr. Townsend's (1909) account of the invasion of 

 New England; these are probably umnated or young birds seeking 

 new territory. But they are not hardy birds, and the next severe 

 winter may result disastrously for the adventurous pioneers. Most 

 of their food is obtained on or near the ground, and when a deep fall 

 of snow covers the ground for a long time and is accompanied by 

 severe cold, most of the wrens succumb to cold and starvation. As 

 a result we have alternating periods of scarcity in the northern States 

 and probably shall never have permanent abundance. Forbush 

 (1929) gives the records for several such periods in New England 

 from 1903 to 1922. 



Even as far south as Washington, D. C, similar fluctuations in 

 numbers have been noted by Dr. Alexander Wetmore (1923), who 

 says: 



Since the winter of 1917-1918, when the Carolina Wren was greatly reduced 

 in numbers in the Wasliington region, this species has increased gradually 

 until the fall of 1921 (after four breeding seasons) it was again fairly common, 

 though still somewhat below its normal abundance. * * * ^ sudden heavy 

 snowfall that continued from January 27 to 29, 1922, when the snow reached 

 the unusual depth of twenty-six inches once more proved disastrous to the bird 

 under discussion. The heavy blanket of snow melted slowly and not until Febru- 

 ary 3 did bare ground appear. * * * Observations during February and 

 March show that the Carolina Wren has again decreased in this region though 

 those that remain are somewhat greater in number than was the case in spring of 

 1918. The supposition advanced in my former note that decrease in this species 

 was due not to cold but to the heavy blanket of snow that buried the normal 

 food supply, seems substantiated. 



And Prof. Maurice Brooks (1936) reports that in West Virginia, 

 where this wren has always been one of the commonest permanent- 

 resident birds, it practically disappeared during the severe winter of 

 1935-36. During late January "this section was subjected to tern- 



