NON-SLIP PADS FOR NESTLINGS 131 



Life how young Woodlarks venture away for a 

 few feet from the nest when alone and undisturbed, 

 and then, when frightened, shrink back to it, as 

 if attached to invisible strings of elastic which 

 pulled them back by contraction. This tendency 

 to " reverse engines " is very marked among many 

 nestlings, and is no doubt connected partly with 

 the habit of backing to the edge or opening of the 

 nest in order to discharge their dung, a piece of 

 instinctive sanitation, and with retirement on alarm 

 without turning round. 



It is particularly well marked in young King- 

 fishers, which run backwards in a most comical 

 way. Iliey are provided with a pad on the hock- 

 joint, on which they rest, like so many young birds, 

 in repose ; but it is not nearly so well developed 

 in them as in young Woodpeckers and Barbets, 

 which have a very marked horny-studded heel- 

 cap, and, as nestlings, do not move on their toes at 

 all, but on the heels, as I was, I believe, the first 

 to record, having reared the Indian Gold-backed 

 Woodpecker {Brachypternus aurantius) and two In- 

 dian Barbets — the Blue-throated (fiyanop asiatica) 

 and the Crimson-breasted {Xantholesma hesma- 

 tocephala) — from the nest, and so noted not only 

 the occurrence of the heel-pad (which had been 

 previously observed in the Wryneck), but also its 

 function. Such a pad has since been observed by 

 Mr. Seth-Smith in the young of a Toucanet (Seleni- 

 dera maculirostris). 



These young Barbets, by the way, had a pecu- 



