5 GO Mr. C. F. M. Swynnerton on 



pungent and nauseating that we had to banish the young 

 birds from the verandah. The cat refused one when hungry, 

 though he eats the full-grown bird practically to repletion ; 

 but the smell may, of course, disappear with death. 



Nestling distiyictiveness in relation to recognition by parents. — 

 T have referi'ed in footnotes to my experiments in this con- 

 nection. That the distinctive element in the call-notes of 

 nestlings may be of use to parents has struck me lately in 

 thinking over the numerous escapes of young birds that, as 

 I have myself seen in relation to snakes, occur through 

 their fluttering down from the nest. Their calls certainly 

 take their parents to them (as I have often seen), while 

 those of another species presumably would not ; yet, to 

 account for the selection of distinctiveness in this con- 

 nection, one would have to imagine that it is a common 

 occurrence for nestlings of more than one species to be 

 out of their nests together. The solicitude shown by the 

 parents for these strayed nestlings (and for caged nestlings) 

 makes one wonder at their alleged ready desertion of those 

 tliat are ejected by Cuckoos. 



Resemblance between mouths of CucJcoo and foster-parenfs 

 nestlings; ejection of fellow-nestlings. — Avery young Cuckoo 

 nestling in a Bishop-bird's nest had the mouth a rather 

 dusky orange, and different, therefore, from the rose- 

 coloured mouth of its surviving fellow-nestling. This, and 

 doubtless numerous other cases, must stand against my 

 suo-gestion made early in this paper. At the same time the 

 orange was turning to salmon (especially under excitement) 

 before the bird's death, a few days later. A fledged Didric 

 Cuckoo, now in my possession, had a glorious mouth when 

 taken from the nest of its Hyphantornis foster-parents — 

 an exaggerated weaver-red, with the pale portions corre- 

 sponding with those of a weaver's mouth. A rush of blood 

 reinforces the pigment, for when the mouth was forcibly 

 opened it was paler, and showed a tell-tale Picarian tongue. 

 Both the Cuckoos had the Weaver's note, " tsip, tsip," and 

 even more than the usual Hyphantornis head-waggle. It 

 would be interesting to know whether these characteristics 



