58 



NORTH AMERICAN FAUNA 69 



I wonder whether Sprunt and Denton's observations were not 

 made during the incubation period when most males avoid the 

 nest site, which is often near the edge of the territory, thus giving 

 the impression of being outside it. When the eggs hatch, the male 

 attends the young along with the female; then the territory no 

 longer has a buffer zone. 



The Swainson^s Warbler builds a large and bulky nest (fig. 25), 

 apparently larger than that of other warblers that nest above the 

 ground. Of two nests, in Dismal Swamp, that I saw under con- 

 struction from the beginning, one took 2 days and one 3 days to 

 complete, and they were built entirely by the females. At one site 

 the male was often close by but visited the nest no more than 

 twice each day during the 3 days of construction ; the male did not 

 assist in construction and apparently visited the nest in search 

 of the female. At the other site, during the initial stages of con- 

 struction the male occasionally accompanied the female to the 

 nest as she flew in with nesting materials; he brought along no 

 material and left almost immediately after arriving at the nest. 



At both these Dismal Swamp nests the female did virtually all 

 of the building before noon. Building of the nest that I watched 



Figure 25.— The large, bulky nest of a Swainson's Warbler (right) and the 

 nest of a nesting associate, the Cardinal, a species nearly twice the size of 

 the warbler. 



