240 Bird - Lore 



birds. Most birds lay one egg each day at about the same time but larger 

 birds, like Hawks, Owls, and Geese, have intervals of two days. 



As the time for incubation approaches, the bare area on the middle of the 

 breast becomes suffused with blood and is termed the 'brood spot,' and the 

 bird becomes 'broody.' Ducks and Geese which have practically no bare area 

 on the breast then proceed to pull out the down from that region so as to bring 

 the eggs in direct contact with the skin. Incidentally, this down forms a 

 blanket with which the eggs are always covered when the Duck leaves them 

 to feed. 



When both birds are colored alike, they usually share equally the duties 

 of incubation, but when the male is brighter than the female, he is not often 

 seen on the nest, the Rose-breasted Grosbeak being an exception. Ordinarily, 

 he either stands guard on the edge of the nest until the female returns from 

 her feeding excursions or else brings food to her. Sometimes he feeds her on 

 the nest but more often he calls, as he approaches, and she flies out to meet 

 him. The easiest way to find a Marsh Hawk's nest is to listen for the returning 

 male and then note from what spot the female flies up to meet him and take 

 the food from his claws. The caie of the female by the male is carried to the 

 extreme by the African Hornbills in which species the male walls up the opening 

 to the nest in a hollow tree with mud until only the female's bill can be pro- 

 truded. He then proceeds to bring her all her food and likewise that for the 

 young later on, for she remains imprisoned until the young are nearly full 

 grown. So great is the task of providing the entire menu for the whole family, 

 we are told, that he becomes excessively thin and often succumbs during 

 inclement weather. 



With a few birds the males do most or all of the incubating and care of the 

 young. This is said to be true of the Emeus and Cassowaries of the East 

 Indies, the Rheas and Tinamous of South America, of Ostriches, at least in 

 captivity, and more particularly of our own Phalaropes. In the case of the 

 Phalaropes the males not only do all of the domestic chores but they are like- 

 wise less brightly marked than the females, apparently a complete reversal of 

 the sexes. 



The period of incubation depends largely on the size of the egg and the 

 nature of the young, larger eggs and those from which precocial young hatch 

 requiring longer periods. The actual time varies from 10 days in the case 

 of the Cowbird to from 50 to 60 with the Ostrich, or even 70 to 80 with 

 the Emeu. Sparrows require 12 to 13; Thrushes, 13 to 14; Hens, 21; 

 Ducks, from 21 to 30, depending largely on the size; Geese, 30 to 35; etc. 

 An apparent exception is the Hummingbird which requires 14 to 15 days but 

 has the smallest egg of all. This may be due to the fact that she receives no 

 help whatsoever from the male and the eggs may become unduly cooled during 

 her feeding excursions, for it is a fact that unusual cooling of the eggs delays 

 the hatching if it does not entirely prevent it. 



