434 I'HILOSOPHICAL TRANSACTIONS. [aNNO 1788, 



being not much larger than the hedge-sparrow's, it necessarily follows, that at 

 first there can be no great difference in the size of the birds just burst from the 

 shell. Of the fallacy of the former assertion also I was some years ago con- 

 vinced, by having found that many cuckoo's eggs were hatched in the nests of 

 other birds after the old cuckoo had disappeared; and by seeing the same fate 

 then attend the nestling sparrows as during the appearance of old cuckoos in this 

 country. But, before proceeding to the facts relating to the death of the young 

 sparrows, it will be proper to state some examples of the incubation of the eggy 

 and the rearing of the young cuckoo; since even the well known fact, that this 

 business is entrusted to the care of other birds, has been controverted by the 

 Hon. Daines Barrington; and since, as it is a fact so much out of the ordinary 

 course of nature, it may still probably be disbelieved by others. 



Exam. 1 . The titlark is frequently selected by the cuckoo to take charge of 

 its young one ; but as it is a bird less familiar than many others, its nest is not 

 so often discovered. I have however had several cuckoo's eggs brought to me 

 that were found in titlark's nests; and had one opportunity of seeing the young 

 cuckoo in the nest of this bird: I saw the old birds feed it repeatedly, and, to 

 satisfy myself that they were really titlarks, shot them both, and found them 

 to be so. 



Exam. 1. A cuckoo laid her egg in a water-wagtail's nest in the thatch of an 

 old cottage. The wagtail sat her usual time, and then hatched all the eggs but 

 one; which, with all the young ones, except the cuckoo was turned out of the 

 nest. The young birds, consisting of 5, were found on a rafter that projected 

 from under the thatch, and with them was the egg^ not in the least injured. On 

 examining the egg^ I found the young wagtail it contained quite perfect, and 

 just in such a state as birds are when ready to be disengaged from the shell. 

 The cuckoo was reared by the wagtails till it was nearly capable of flying, when 

 it was killed by an accident. 



Exam. 3. A hedge-sparrow built her nest in a hawthorn bush in a timber- 

 yard: after she had laid 2 eggs, a cuckoo dropped in a 3d. The sparrow con- 

 tinued laying, as if nothing had happened, till she had laid 5, her usual number, 

 and then sat. On inspecting the nest, June 20, 1786, I found that the bird 

 had hatched this morning, and that every thing but the young cuckoo was 

 thrown out. Under the nest I found 1 of the young hedge-sparrows dead, and 

 1 egg by the side of the nest entangled with the coarse woody materials that 

 formed its outside covering. On examining the egg, I found one end of the 

 shell a little cracked, and could see that the sparrow it contained was yet alive. 

 It was then restored to the nest, but in a few minutes was thrown out. The 

 egg being again suspended by the outside of the nest, was saved a second time 

 from breaking. To see what would happen if the cuckoo was removed, I took 



