GRASPING IN BIRDS OF PREY

[darren.naish@port.ac.uk]

Tim Williams wrote...

> The secretary bird (_Sagittarius serpentarius_), like most (?all)
> extant birds of prey, has a pes designed for grasping and holding
> prey.  

New World vultures (aka cathartids or vulturids) have weak feet with 
poorly developed trochleae and flexor tubercles, shallow collateral 
fossae and only gently curved unguals when compared with other birds 
of prey. As is well known, they have poor grasping abilities and don't 
use their feet to manipulate objects.

As has been noted here before (long long ago), secretary birds have 
proportionally short toes and relatively blunt claws compared to most 
other birds of prey. Makes sense if you walk around on the savannah, 
bashing the hell out of snakes and other small vertebrates with your 
feet. They are still pretty good at grasping etc though.

"You're scary looking"
"You should have seen my father"

DARREN NAISH 
PALAEOBIOLOGY RESEARCH GROUP
School of Earth & Environmental Sciences
UNIVERSITY OF PORTSMOUTH
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