Development and behaviour of a yellow-billed hornbill (Lophoceros Flavirostris Leucomelas) chick.

Abstract

Development and behaviour of a yellow-billed hornbill (Lophoceros Flavirostris Leucomelas) chick

A brief report on the development of dorsal air sacs in hand reared Von der Decken’s hornbills (Tockus deckeni)

“…Prozesky 7 and Kemp 10 observed that air sacs in wild Lophoceros and Tockus chicks they studied inflate when the birds were handled or prodded, possibly promoting the hypothesis that these structures provide pneumatic protection. However, similar to the study by Downs et al, 8 our observations disagree with this, as the air sacs were found to be extremely soft and malleable to touch and would not provide adequate cushioning.…”

“…5,6 The female usually only emerges after the chicks are fairly well-developed. 5,6 Thus these structures are believed to provide pneumatic protection to cushion chicks in a crowded, cramped nest 7 and also to aid in thermoregulation. 8,9…”

“…It has been described as early as the 1970s, in wreathed hornbills ( Rhyticeros undulatus ), rhinoceros hornbills ( Buceros rhinoceros ), great hornbills ( Buceros bicornis ) 9 and in some Lophoceros and Tockus hornbills. 7,8,10 It is also reported to exist in the southern ground hornbill ( Bucorvus leadbeateri ), 11 though taxonomically they are from a different family (Bucorvidae), and differ in some nesting behaviours such as not sealing up their nest cavities and having helpers to raise their chicks. 12,13 A list of hornbill species known to develop these air sacs is found in Table 1.…”