Figure 1. — Summer and winter homes of the black and white warbler, 

 a very slow migrant as the birds nesting in the northern part of the 

 country take 50 days to cross the breeding range. The speed of 

 migration is shown in figure 2. (See p. 14.) 



spends the winter in southern Florida, the West Indies, central Mexico, 

 Central America, and northwestern South America. In the southern 

 part of its breeding range it is nesting in April, but those that summer 

 in New Brunswick do not reach their nesting grounds before the 

 middle of May. Therefore, about 50 days are required for these north- 

 bound birds to cross the breeding range, and if 60 days be allowed for 

 nest building, egg laying, incubation, care of young, and molt, they 

 would not be ready to start southward before the middle of July 



889511— 5C 



13 



