212 



14 



for a short time, feeling with the extremity of its wings, as if to be convinced whether the 

 business was properly executed, and then dropped into the nest again. With these, the 

 extremities of the wings," he continues, " I have often seen it examine, as it were, the egg 

 and nestling before it began its operations ; and the nice sensibilities which these parts seem 

 to possess, seemed sufficiently to compensate the want of sight, which, as yet, it was destitute 

 of. I afterwards put in an egg ; and this by a similar process was conveyed to the edge of the 

 nest and thrown out. These experiments I have since repeated several times in different nests, 

 and have always found the young Cuckoo disposed to act in the same manner." He then states 

 that its shape is well adapted for this purpose, as its back is very broad, with a depression in 

 the middle, which is not filled up until it is about twelve days old. When two Cuckoo's eggs, 

 he says, happen to be deposited in the same nest, a severe contest takes place between the newly 

 hatched young, and continues till the weaker is rejected. 



Macgillivray, who reproduces the above notes by Dr. Jenner, gives also (Brit. B. iii. 

 pp. 128-131) some excellent field-notes communicated to him by one of his correspondents, 

 which I transcribe as follows : — " In this part of the country the nest of the Titlark is the one 

 almost invariably selected by the Cuckoos for depositing their eggs ; indeed I have never seen 

 them in any other. In Balgornie Moor, situate in the extremity of the parish of Bathgate, on 

 Saturday the 19th of May, 1838, a pair of Titlarks finished their nest. The female laid an egg 

 upon Sunday, Monday, and Tuesday. During one of these days a Cuckoo took the opportunity 

 of dropping her egg amongst those of the Titlark. How she succeeded in doing this I know 

 not, as the nest was built upon the side of a deep perpendicular ditch, the top of which was 

 thickly covered over with strong heath in the shape of a dome, and the entrance into it was very 

 narrow. 



" Nearly the same period of incubation seems to be required for hatching both kinds of eggs. 

 Upon Wednesday morning, the 23rd, the female Titlark began to sit upon the eggs, and upon 

 that day fortnight, the 6th of June, they were all hatched. I saw them a short time after this 

 had taken place. The young Cuckoo appeared to be about one third larger than the Titlarks, 

 and of a dark colour. It was constantly gaping for food. Upon its back, from the shoulders 

 downwards, was a peculiar depression, which I do not recollect having seen in any other young 

 bird. On the afternoon of the 10th two of the Titlarks were found lying dead at the bottom of 

 the ditch. The other one had disappeared. 



" On Wednesday afternoon, the 13th, the feathers of this young bird had a strong resem- 

 blance to the prickles of the hedgehog, and it had grown so fast that it nearly filled the whole 

 nest. When any thing touched it unexpectedly, as has been remarked by Mr. Blackwall, it 

 threw itself back with considerable force. It was bold and fierce. When I put my finger near 

 its bill it ruffled its feathers, stood upon its legs, struck at it with its wings, and even attempted 

 to bite. For several hours I watched the motions of the foster-parents in order to ascertain 

 whether they were still kind to the charge committed to their trust; and they continued to pay 

 it the same unwearied attention. During the space of an hour they fed it generally ten or 

 twelve times. The female occasionally remained in the nest several minutes. Both were 

 exceedingly shy and cunning. So long as I was within sight of them they would not feed the 



