KHASIA HILLS CUCKOO 99 



working in the pinewoods surrounding the open patch in which the 

 fantail warblers were breeding and doubtless drove these little birds 

 away and so deprived the cuckoo of foster parents during the latter 

 period of her laying, or probably larger series would have been ob- 

 tained in that particular patch of grassland. The various series 

 prove satisfactorily that eggs are normally deposited every alternate 

 day and, also, that there is no interval in the laying period dividing 

 it into two. 



The weights of 1,368 eggs of the Kliasia Hills cuckoo are as fol- 

 lows: Average weight 231; maximum 307; minimum 153 milli- 

 grams; this latter is, however, an abnormally small light egg and 

 very few will be found less than 180 milligrams. 



The same number of eggs measure: Average 23.76 by 17.43; 

 maxima, 28.5 by 18.0 and 27.1 by 20.0; minima 20.9 by 16.3 and 23.4 

 by 15.0 millimeters. 



I should, perhaps, not omit to say that though the generally ac- 

 cepted idea that cuckoos' eggs can be distinguished by their weight is 

 in most cases correct, it is not always so. For instance, I have 37 

 eggs of this cuckoo taken in shrikes' nests, and a comparison of 

 weights and measures of the eggs of the two species is as follows : 



C. c. bakeri, 37 eggs Lanius n. nigriceps, 100 eggs 

 Average size: 23.56 by 17.50 mm. 23.60 by 17.9 ram. 



Average weight : 232 rag. 215 mg. 



Maximum weight: 266 mg. 249 mg. 



Minimum weight: 190 mg. 185 mg. 



The comparative weight of the eggs of different species of birds 

 varies greatly. Thus Anthus eggs are normally very light while the 

 eggs of Passer are very heavy, two of the former about equaling 

 three of the latter of the same size and, in a few cases, otherwise 

 indistinguishable in coloring, shape, etc. Hoopoes' and spine-tailed 

 swifts' eggs are very heavy, far more so in comparison with their 

 size than those of cuckoos. 



This shows that weight alone in some cases does not suflBce to dis- 

 tinguish cuckoos' eggs from their fosterers' eggs, and other compari- 

 sons of cuckoos' eggs with those of other species could be quoted to 

 confirm this. The hard gritty shell wdth fine pits at wide intervals 

 is a further good distinguishing feature of cuckoos' eggs, while when 

 blowing it is noticeable that most cuckoos' eggs have the yolks tinged 

 with flesh color and very pale, while the white is rather more opaque, 

 like the white of a duck's egg when compared with that of a fowl. 



In Europe it is very rare to find two eggs of cuckoos in a nest 

 laid by the same female; in India this is not so rare, and I have 

 on three occasions found three eggs of the same cuckoo in one nest. 



