Re: GANGING CROWS & LIZARDS

["Matthew Troutman" <m_troutman@hotmail.com>]

<<I recall an article in _Scientific American_ (or may have been
_American Naturalist_... their formats are unnervingly similar to the
easily confused) about ganging behaviour in corvids, was published
some time in the last 2 years. Juvenile ravens ganged together to
harass pairs of adults that had claimed a carrion find. The juveniles
mobbed the adults until they were so intimidated as to leave.. the
juveniles could then share the spoils. Seeing as the juveniles did
not normally associate with one another, this is a sort of
opportunistic sociality I suppose.>>

I have not seen the original paper but I can contribute some pers. obs. to 
this discussion on the corvid side of it.

While walking through a prarie savannah in an open part, two aquaintances 
and I witnessed one of the most interesting bird watching experiences of my 
life.  Sitting up on a dead tree (_Quercus_ sp. I believe) was a subadult 
Cooper's Hawk (_Accipiter cooperii_) minding its own business and being 
ganged up on by a group of Blue Jays (_Cyanocitta cristata_).  I have seen 
various corvids stage rather coordinated attacks on cats and dogs and 
squirrels but what set this one apart was the extremely well-coordinated 
individual attacks being done by 5 jay individuals.  One jay would get into 
the hawk's "bubble" and the bird would attack the smaller jay while another 
jay would hop up and peck the hawk from the back, taking off in time to 
escape while the hawk lounged in the new direction, after which being 
attacked by the first bird!  It was an endless cycle that also included some 
use of vocalizations to get the hawk's attention.  This was very 
well-coordinated from mine and my aquaintances' standpoints, set apart 
greatly from other corvid attacks we had witnessed.

I stop short of calling this a "pack", but that would probably be an 
accurate term.  Clearly if it was a "gang", this was a rather unique one.

Matt Troutman
m_troutman@hotmail.com


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