Hatchin(j its oivii E(/gs. 223 



wlii(;li it fed tlie young with some green substance, apparently 

 caterpillars, as I could see with my glasses, and then covered 

 it with her body again for about a quarter of an hour. The 

 mother left the spot on this occasion again by flying up from 

 the neighbouring place before mentioned, and not imme- 

 diately from the nest. Within a few minutes she returned, 

 with a similar lot of food, and after feeding the young one, 

 retired in the same way as was before described. After the 

 second return and feeding the warming of the young bird 

 was again repeated. After a good quarter of an hour in my 

 hiding-place I left the spot without distvirbing the old bird. 



All through my period of observation in this part of the 

 forest I had noticed the unusual frequency of the calls of the 

 male Cuckoo. I counted at least six individuals challeneinsr 

 one another with their songs. In the higher wood close by 

 I had listened at short intervals to the furious blows of the 

 Aving exchanged in combat by the males and to the call-notes 

 of both sexes. I had an entertaining view of the proceedings 

 of the amorous birds, as I passed on my way shortly after- 

 wards. On the tops of the oaks and pine$ sat the excited 

 males, with their tails carried high and their wings drooping 

 down, repeating their usual call-notes, among which the 

 ordinary " cuckoo " was often prolonged into " cuc-cuc-koo/' 

 and in other cases was shortly and abruptly broken off in 

 the middle. Every now^ and then they dived into the 

 branches in pursuit of the hens, which were recognizable by 

 their paler and browner coloration. In short, this particular 

 spot in the forest was evidently a special rendezvous of 

 Cuckoos. In spite of the unseasonable weather this day 

 (overcast sky and frosty wind), there was a singing and 

 fighting going on which could hardly have been exceeded in 

 the warmest day of May or June. 



Anxious to ascertain the reason of such a concourse of 

 Cuckoos at this spot, I dived into the surrounding wood, 

 which was that from which I had seen the mother Cuckoo 

 bring food for her young one. I discovered here, on a 

 gioup of oaks, a large colony of caterpillars of Toi'trix viri- 

 duna, which were easily seen from a distance hanging by 



