F. H. BAHR: DEVELOPMENT OF A CUCKOO. 368 



From a perusal of the above figures, another reiu ark- 

 able fact comes to lig'ht. It will be seen that on the 

 fourteenth day of its life the Cuckoo weighed as much as 

 on the day it flew ; and that it decreased half-an-ounce in 

 the last three days ! The only explanation of this, I take 

 it, is that its whole energy was devoted to growing feathers, 

 and that the shedding of the feather-sheaths must largely 

 account for this curious decrease. For a few hours during 

 the last few days of these observations, the Cuckoo was 

 confined in a cage, but, as I shall exj)lain later, the con- 

 sequently lessened food-supply cannot, in my opinion, be 

 the cause of this loss in weight. I liojje, on a future 

 occasion, to be able to verify these observations, and by 

 the use of a finer Aveighing machine to be able to record 

 the more gradual increase of weight. 



At first the bird evinced no fear of man, and on 

 approach would open its beak, begging for food. By the 

 sixteenth day the sense of fear had developed, and when 

 the nest was approached it would j^uff out its throat, snap 

 its bill, and strike at the offender's hand, assuming quite 

 an alarming asj^ect. When placed on the board, for 

 photographic purj^oses, it was able to crawl, and to take 

 quite an interest in the surroundings. It answered the 

 call of its foster-parents with alacrity, the answer taking 

 the form of a miserable squeak, comparable, as has been 

 fittingly put, to the twisting of a glass stopper in a bottle. 

 It indicates one thing only ; food, always more food ! ! 



By the seventeenth day the Cuckoo completely filled the 

 nest, and by the nineteenth was sitting outside it. By the 

 twentieth day the primaries had grown considerably, and 

 it was evident that the bird would fly in a few days. I 

 therefore placed it on a suitable branch, and focussing the 

 camera on it, proceeded to take pictures of the Wagtails 

 attempting to allay its insatiable appetite. I found this 

 not a very easy task, as both were very nervous and only 

 the hen could be induced to ap^Droach. They appeared 

 every ten minutes with their beaks full of flies, and other 

 dainties, which the cock invariably ate himself. When 



