124 SEX-LORE 



attention from her little ones to herself by pretending 

 to have broken her wing or to Jbe lame. Other birds 

 savagely attack intruders; some have even been 

 known to leave their nest carrying the eggs in their 

 beaks when there has been a suspicion of danger. 

 Certain species carry their young about with them; 

 some, as the woodcock, between the legs, holding 

 them down with the beak; others, like the grebe and 

 the swan, on the back. Birds seem to have an in- 

 herent sense of cleanliness, and with few exceptions 

 most young birds and their nests are kept in a scru- 

 pulously clean condition. All refuse is cast out of 

 the nest, and the nestlings are taught to void their 

 excretions over the edge. 



The young are fed for a period by the parents, 

 except those that are born fully mature and can seek 

 their own food immediately after birth. When the 

 young are fed on insects, the parents have a long and 

 weary task hunting all day for them. Pycraft relates 

 that " a pair of blue titmice have been observed to 

 make no less than 475 journeys to the nest during a 

 day's foraging extending over 17 hours." Some birds 

 feed their offspring on regurgitated food, which is 

 food partly digested and then brought up again for 

 the young. Young pelicans take their food from the 

 pouch-like bill of the mother (Fig. 45). Cormorants 

 thrust their bills down the mother's throat into her 

 stomach and help themselves to food. Young pigeons 

 are fed on so-called pigeon's milk, which is partly 

 digested food and partly a secretion from the crop of 

 the pigeon. Young petrels are fed on an oil distilled 

 from the fish which form the food of the parents. 

 This oil is also used as a weapon of defence by both 



