1917-] Br cedhig-hahits of the Cuckoo. 217 



Here^ «g'ii", tLe often referred-to Cow-birds differ, since 

 from one to seven e<?gs of some species are found in the same 

 nest, two or more being probably laid by the same bird. 



There are also no grounds for doubting the correctness 

 of Dr. Rey's conclusion that the laying period varies greatly 

 in different localities, both in date and duration, and corre- 

 sponds with that of the species selected as foster-parent, 

 though it is not so easy to reconcile this with his view that 

 each female lays some twenty eggs yeai'ly, since, if laid on 

 alternate days, this means forty days out of a possible period 

 of some three months. 



Finally, as regards his last conclusion, one would imagine 

 that, whenever possible, the Cuckoo would insert its egg in 

 the nest when the rightful owners were absent, both to avoid 

 alarming tiiera and meeting with opposition, and thus I 

 rather doubt if heated struggles with the foster-parents are 

 not very exceptional. 



There is still one point on which Dr. Rey gives little 

 information : — What subsequent interest^ if any, does the 

 Cuckoo take in he?- eggs and young ? 



He meutions that the Cuckoo has been observed watching 

 the nest for some days afterwards, and that, on occasions, 

 other eggs are removed from the nest subsequently. 



I can supply the following data in addition : — 



(a) My late brother, when at school, found a Hedge- 

 Sparrow's nest with a Cuckoo's egg in it, which, 

 luckily, was in the headmaster's garden and secure 

 from molestation. A. few days subsequently he 

 heard the Hedge-Sparrows in a great state of alarm 

 and saw a Cuckoo visiting the nest, and on again 

 examining it found that another egg of the foster- 

 parents had been ejected. 



{b) A farmer in Midlothian, who was interested in orni- 

 thology and whose word I have no reason to doubt, 

 assured me that he had actually seen a young Cuckoo, 

 in a Meadow-Pipit's nest close to his house, being fed 

 by a Cuckoo. 



