PARENT AND OFFSPRING 121 



turns at the nursing; they relieve each other at 

 certain intervals, bowing in a quaint manner and 

 carefully examining the egg before it is handed over. 

 These birds have so great a desire to brood that, if 

 anything happens to their own egg, they will steal 

 another for this purpose. Truly a fine example of 

 parental feeling. 



The majority of these classes of birds, however, 

 make nests, which, though perhaps poorly formed, are 

 yet warm and soft for the eggs. It is in these cases 

 always the female that broods; and this must always 

 be considered a progressive step. Sometimes, as in the 

 case of the duck or fowl, the male departs and does 

 not return until the young are nearly fledged. But 

 in many cases the male shares the duty of his mate, 

 either relieving her of the brooding for awhile, or 

 remaining to feed her and protect her against any 

 intruders. Both parents are thus at hand to help 

 when the young ones break their shells. We can 

 here recognize the first beginnings of family feelings. 

 The newly hatched young are not quite so well de- 

 veloped as those of the class previously mentioned, 

 and require for a time the protection and warmth of 

 the mother's wing. They are, however, very soon 

 active and able to manage for themselves. Among 

 the swimming birds parental care lasts from two to 

 four weeks, but never longer. 



We can establish a further progressive step in those 

 birds that show a still greater care in the preparation 

 of their nests. They also generally give the most 

 intelligent and assiduous attention to the young 

 brood. There are, of course, exceptions to this rule; 

 evolution does not always proceed in straight lines. 



