24 WARM-WEATHER BIRDS. 
male of one so closely resembles the female of the 
other, that size and slight variation of color form the 
only guides. 
It is both a timber and prairie bird. Its clutch is 
from ten to twelve pure white eggs; like the bluewing, 
southern birds frequently have two hatchings during 
the year. For food and nesting range, see chart. 
Length 16.50; wing 7.50; tarsus 1.30; extent 24.00, 
middle toe 1.50. 
SUBGENUS Anas. 
Anas boschas—Reb-LEG MALLARD.—Habitat.—North 
America to about 65° north latitude, south to Central 
America and West Indies. The migration of this 
our common timber and river duck in the south, the 
spring, summer and fall mallard of our northwest 
boundary, makes its first appearance in the spring, 
after the ice has entirely disappeared. The first issue 
arrives about latitude 36° during the months of Febru- 
ary or March, according as the season is early or late, 
and remains for eight or ten days. The second follows 
a few days later, which also stays seven or eight days 
according to the amount of oakmast in the glades and 
smartweed in the timbered lakes. The third drifts 
through, and by the ist of April are nearly gone. 
Those birds which travel up the Missouri stock the 
northwest; the Mississippi flight goes north and west; 
the Illinois River flight goes over the Fox Lake re- 
gion, and some branching off, meeting others from the 
Wabash, go around Lake Michigan to the northeast. 
The first fall flight consists of local ducks from Mich- 
igan, Lowa, Wisconsin up to the Minnesota southern 
