VOL. XIV.] OBSEIIVATIONS ON A CUCKOO. 231 



Tree-Pipit, did this Cuckoo in 1919 and 1920 fail to 

 utilize Meadow-Pipits. 



(d) The Cuckoo finds a nest by watching the owners 

 of it at the stage of, or in the process of building. 



After the fosterer has begun to lay, the Cuckoo 

 often makes a preliminary visit to the nest, and in such 

 circumstances it was invariably found that she made 

 use of the nest a few days afterwards. 



{e) The sight of her natural fosterers preparing their 

 own nests, in all probability, has a stimulating effect 

 upon the Cuckoo's natural desire to reproduce her 

 species. 



(/) Although on many occasions this Cuckoo was 

 seen to watch fosterers in the state or in the act of nest- 

 building, she was never seen to fly down to the nest until 

 it already possessed at least one egg of the fosterer. 



(g) After she had once selected a fosterer and flown 

 to its nest, she placed her egg therein even if it were 

 deserted. 



(/?■) Preparatory to laying, the Cuckoo takes up a 

 position commanding a view of the nest of her intended 

 victim and sits usually from half an hour to two and a 

 half hours, mostly motionless and with e^^es concentrated 

 upon her fosterers and/or their nesting site. If disturbed 

 she will readily return to the same perch. 



(i) When ready to lay her egg the Cuckoo launches 

 from her perch and with laden flight glides down beside 

 the nest, with outstretched wings which she slowly flaps, 

 if necessary, to reach the nest-side. This is probably 

 true in the case of all ground-building fosterers, but what 

 occurs in other circumstances has yet to be established. 



(_;') Except on the two occasions when she deposited 

 her egg in a nest of eggs already under incubation, this 

 Cuckoo only remained beside the nest from thirty to 

 ninety seconds, for the purpose of laying her egg and 

 inserting it in the fosterer's nest. 



{k) The fosterer's egg removed by this Cuckoo from 

 the nest after depositing her own was, according to 

 the length of visit beside the nest, either swallowed at 

 the nest-side or carried in her beak to a conveniently 

 adjacent tree where the egg may or may not have 

 been swallowed. 



(1) After this Cuckoo had laid and deposited her 

 egg and disposed of that of the fosterer, she resumed 

 her normal lively condition, usually uttering her cheerful 



