866 Mr. C. Ingram on the [Ibis, 



In Picarian birds, on the otiier liand, I believe there is 

 seldom, if ever, any conspicuous enlargement of tlie rictus, 

 even when a species nests in dark or semi-obscure situations. 

 An exphmation of this apparent anomaly will probably be 

 forthcoming when we more thoroughly investigate their 

 mode of conveying food to their young. I believe the 

 explanation lies in the fact that the majority of these birds 

 feed their young — during the earlier stages, at any rate — by 

 regurgitation. This is almost certainly the case with the 

 Common Swift [Micropus apus), whose naked nestlings are 

 hatched in obscure situations without a vestige of any 

 gape-flange. Despite long vigils in dai'k and dusty attics, I 

 have never succeeded in actually seeing Swifts feed their 

 young (which, by tlie way, they do at very long intervals of 

 time), but, from the actions of the parents and the gropino- 

 movements of the nestlings, I have no doubt that they 

 are nourished in their infancj'^ entirely by regurgitation *. 

 This being so, a visual stimulus is scarcely necessary, since 

 the transference of food can be safely accomplished imme- 

 diately contact is obtained between the mouths of the giver 

 and receiver, and this contact is probably obtained more 

 often by a sense of touch than by sight. 



While referring to the nestling Swift it might be worth 

 while mentioning an interesting habit I noticed last year, 

 when handling a young bird about three or four days old. 

 Tliis individual, evidently feeling ill at ease in the hollow of 

 my hand, evinced a strong and unmistakable desire to climb 

 upwards. It was apparent that this instinct was excited by 

 the irregular surface upon which it found itself, and I have 

 no doubt its function is to enable the nestling to retain its 

 position on the shallow platform that dues duty for a 

 nursery. But its method of climbing (or rather its attempt 

 to climb, for it was not very successful) seemed to me the 

 point of chief interest. Gripping \evy vigorously with its 



* Nightjars have been proved to teed their young by regurgitation 

 (Kirkman, * Wild Life,' vol. iii.) Swifts are said to convey food to their 

 nestlings in the form of " bundles " of insects carried nnder their tongue 

 (Kirlanan, 'British Bird Book,' ii. p. 3C0). This fact was recorded also 

 by Gilbert White in a letter to Bairington dated Sept. 28, 1774. 



