204 LIFE-HISTORIES OF BIRDS 



Both birds are exceedingly jealous of intruders, and will not 

 even permit one of their own kind to approach within a few 

 paces of the nest, without wreaking summary vengeance 

 upon such temerity. In the case of human interference, 

 they do not hesitate to show their indignation by violent 

 hissing, and a vehement clicking of the bill ; and will often 

 venture to expel the intruder by striking at him with out- 

 stretched claws. The male has been known to administer to 

 his partner's well-being by furnishing a dainty morsel when 

 she has been confined to the nest. The period of incuba- 

 tion ranges from seventeen to eighteen days. But a single 

 brood is raised in a season. 



The young are carefully nourished by their parents, who 

 labor with indefatigable diligence to provide them with a 

 full supply of the necessary articles of diet. Not only at 

 night, but also frequently during the day, one or the other 

 parent is absent from the nest on this important business. 

 Their demands for food are so importunate that diur- 

 nal excursions are indispensable. It is seldom that the 

 nests are found to contain articles of food, as is the case 

 with those of some species, but in a few instances we have 

 noticed a manifestation of this parental disposition of provi- 

 dence, but only where the brood was limited to the minimum 

 number. Their food consists at first of the flesh of the ani- 

 mals taken in capture, entirely divested of dermal appen- 

 dages ; but as they increase in size and age, the entire animal 

 is administered, which they are required to separate for them- 

 selves, preparatory to swallowing. Where there are several 

 birds in the same nest, there is often manifested a spirit of 

 contention, particularly when a very choice article is thrown 

 into the nest, which inevitably terminates in the strongest 

 individual's favor, who thus secures the lion's share. But, 

 ordinarily, to guard against such events, the parents are very 

 impartial in the apportionment of the food, and take especial 

 pains not to administer to the same individual twice in suc- 

 cession, save in instances where there is one of a more vo- 



