Jan.,1 Heartland, A Study of Birds at Breeding Time. 133 



A STUDY OF BIRDS AT BREEDING TIME. 

 By G. A. Keartland. 



{Read before the Field Naturalists' Club of Victoria, \$th Sept., 191 5.) 

 During the past few years much attention has been paid to 

 bird photography, and by that means we have been familiarized 

 with the forms of the nests which many of our birds construct. 

 Then we have had photographs of the young ones in the various 

 stages of development, thus showing that, whilst some birds 

 undergo scarcely any change in colour or markings between 

 the time they are able to fly and arriving at maturity, others 

 require periods of from six months to four or five years before 

 acquiring mature plumage. Take the well-known Mudlark, 

 Grallina picata, as an instance. Unless taken in the hand and 

 the softness of the feathers noted, it is impossible to distinguish 

 a bird a month old from the parent of the same sex. Others, 

 like the Stubble Quail, Coturnix pectoralis, are six months old 

 before the sexes can be distinguished by the plumage, and at 

 that age the young ones are like their parents. 



Then we have the Night Heron, Nycticorax caledonicus, the 

 young of which have been mistaken for birds of another species, 

 owing to the great difference in plumage. How long they are 

 before assuming adult livery is doubtful — probably two years. 

 The Pacific Gull, Gabianus fiacificus, takes three or four years 

 in changing from the modest brown of the young to the 

 beautiful white and black of the old ones. This list might be 

 extended, but my main object in writing these lines is to draw 

 the attention of members to the study of the work of incubation, 

 and to try if we can ascertain in what species both sexes share 

 the labour. 



The same instinct which influences our domestic poultry in 

 laying a greater number of eggs when the nests are cleared 

 every day, and which causes the hen to become broody if the 

 eggs are allowed to accumulate until about a dozen are laid, 

 appears to exist in many of our wild birds. I know of instances 

 in which the nests of both Mud-Larks, Grallina picata, and 

 Black-and- White Fantails, Sauloprocta motacilloides, were robbed 

 or destroyed three times, and then the birds laid a fourth clutch 

 and reared their broods. Whilst at the Fitzroy River, X W.A., 

 I found three nests of the Little Friar-bird, Philemon sordidus, 

 each containing young ones, which the black boy who 

 accompanied me appropriated as a delicacy. On visiting the 

 same trees a fortnight later I found that each pair of birds had 

 built a fresh nest, and had already laid a full clutch of eggs. 



Of course, it is well known that amongsl the pigeons and doves 

 both sexes take part in the sitting. The female generally does 

 all the night work, but is relieved during the day by her mate, 

 and both parents share the task of feeding the young until 



