MAY 85 



crime, perpetrated year after year with impunity. That 

 the details have at last been unravelled is a fresh 

 instance of the necessity for patient observation and 

 rigid concentration upon some specific branch of 

 research, whereby alone any advance can be achieved 

 in the field of science. Such advance has been accom- 

 plished lately by Mr. Edgar Chance, who during the 

 last four years has acted as private detective on the 

 nefarious proceedings of the cuckoo. 



Beginning his study in the spring of 1918, Mr. Chance 

 had satisfied himself by the end of the summer of 1919 

 that, whereas most birds lay an egg each day till the 

 appointed number is complete, the female cuckoo lays 

 only on alternate days. Further observation in 1920 

 proved that, while most birds lay early in the morning, 

 the cuckoo prefers the afternoon. Concentrating obser- 

 vation upon a single cuckoo, he found after she had 

 laid eleven eggs, that he could calculate precisely when 

 the next would be laid, and he actually witnessed the 

 laying of nine more eggs, making the astonishing total 

 of twenty eggs laid by this most unmotherly of mothers 

 in a single season. Hitherto it had been understood 

 that the cuckoo laid her egg on the ground, and then 

 carried it in her beak to deposit it in the nest she had 

 chosen. In the summer of 1921 Mr. Chance secured 

 photographic evidence that the bird's procedure was 

 after another manner. In May of that year the same 

 cuckoo as he had had under observation in the previous 

 three seasons returned for the fourth time to the scene 

 of her former activity, and on the 12th of the month 

 laid her first egg in the presence of Mr. Chance and two 



