BEITISH WARBLERS 



and as to the period during which the eggs are laid the species 

 does not seem to differ, on the whole, from others closely 

 allied, one being laid as a rule every twenty-four hours. The 

 behaviour of the male, directly the first egg is laid, is inte- 

 resting, as he at once takes his share in sitting upon and 

 maintaining it at the proper temperature. Judging from their 

 actions incubation proper does not commence until the fourth 

 or fifth egg — according to the number of the clutch — is laid ; 

 for directly the full number is completed their anxiety not 

 to leave them too long exposed is very apparent. I have 

 taken particular notice of the behaviour exhibited by the 

 sexes during the period of incubation, and it does not seem 

 to me to show any very striking difference. Nineteen minutes 

 is the longest period I have recorded that the female has 

 remained upon the eggs, and seventeen minutes in the case 

 of the male. The one leaves the nest immediately upon the 

 appearance of the other, and the male will sometimes sing 

 on the way to the nest, and even while on the nest itself. 

 The female utters a low quiet note as she approaches and is 

 desirous of replacing her mate, and whilst sitting upon the 

 nest pecks at and appears to be arranging the material in 

 the interior. There is a difference — but whether such differ- 

 ence is constant, or happens only to have been the case in 

 those instances I have had under my notice, it is impossible 

 to say without further investigation — in the direction in which 

 the sexes face while incubating ; each one seems to have its 

 own particular direction, which it adheres to with more or less 

 regularity. 



Incubation lasts fourteen days, calculating from the day 

 upon which the last egg of the clutch is laid ; and as soon as 

 the young are hatched the parents become decidedly more 

 anxious, betraying uneasiness in their movements. Of the 

 two the male is the more nervous, approaching the nest with 

 great timidity and only with difficulty overcoming his alarm 

 at one's presence. But, as already mentioned, the excitement 

 displayed by the species as a whole, both at this and other 



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