VOL. XIV.] LETTERS. 71 



F. Simmonds, senior and junior, she laid her sixteenth egg. A Tree- 

 Pipit {Anthus t. trivialis) had to do duty for the fifteenth egg, there 

 being no Meadow- Pipit's {Anthus pratensis) nest ready that day owing 

 to the unfortunate depredations of a Kestrel {Falco t. tinnuncuhis^. 

 with young, subsequently destroyed, which in the preceding week had 

 reduced the number of pairs of Meadow-Pipits on the common from 

 nine to four. With a shortage of Meadow-Pipits' nests threatening, 

 the seventeenth egg was laid after an interval of four instead of two 

 days, i.e., on Wednesday, June i6th, and thereafter laying with the 

 usual forty-eight hour intervals the Cuckoo deposited her twentieth 

 egg on Tuesday, June 22nd Two days later (Thursday, June 24th), 

 instead of laying, she fiew down to the only remaining Meadow-Pipit's 

 nest which that day contained one egg, but though she did the same 

 thing again on Saturday, June 26th, by which time the Meadow-Pipits 

 had deserted the nest, it was not until the fifth day after laying her 

 tw-entieth egg that she deposited her twenty-first and last egg, on 

 Sunday, June 27th, in the deserted nest. 



Last year's study enabled me to express the opinion that provided the 

 facilities, a Cuckoo — or at least this Cuckoo — would lay approximately 

 every forty-eight hours. Thus the return of this Cuckoo for a third 

 season's study enabled me this year to prove that, with extraordinary 

 regularity, she would, and when assisted by the provision of Meadow- 

 Pipit's nests did, lay every other day ; and by the time the Cuckoo 

 had laid ten eggs this season she had taught me so much that I actually 

 watched her lay and deposit nine of the remaining eleven eggs of the 

 series. 



I question whether ever before anyone has been possessed of the 

 necessary information to be able to foretell both when and where a 

 Cuckoo would lay her eggs, so as to have the satisfaction as I had this 

 year of taking friends out on different days to see the Cuckoo take up 

 her position often in a given tree to watch, frequently motionless for 

 an hour or more at a time, her previously selected victim and finally 

 glide down in the most fascinating manner beside the appointed nest, 

 lay and deposit with her beak with remarkable rapidity the egg, and 

 fly away with an egg of the foster-parent in her beak which she in- 

 variably removed from the nest in exchange for her own. 



Having achieved my ambition this year to break all previous records 

 in the number of eggs observed as laid, I hope if the same Cuckoo 

 returns next season to be able to get the whole egg-laying process 

 filmed. 



On no occasion during the three years has this Cuckoo deposited more 

 than one egg in any one nest, even though force of circumstances must 

 several times have sorely tempted her to adopt this suicidal habit. 

 As I have already shown, when suitable nests appeared unlikely to 

 be available as required, she twice this year temporarily discontinued 

 laying. Or, to express the same thing rather differently, this Cuckoo 

 only persisted in laying every other day so long as a fresh nest (as 

 opposed to one she had already victimized) of the Meadow-Pipit (her 

 favourite dupe) was made available for her. 



If I may I will send you for publication at a subsequent date com- 

 prehensive notes detailing {a) the methods adopted for the successful 

 observation of this Cuckoo day by day ; {b) the extremely interesting 

 behaviour of the female Cuckoo, with references to her one, two and 

 sometimes three attentive mates ; (c) the actual circumstances under 

 which each of the twenty-one eggs was found and the precise hour at 

 which the nine eggs were seen laid and deposited ; {d) the manner in 



