in article , Malcolm at
wrote on 27/1/03 10:06 pm:

snip
sacha wrote:
I was fascinated to learn about the rooks that the reason
one sees them flying in pairs to pick up twigs but only one of them coming
back with a stick, is that the unencumbered one is the male riding 'shotgun'
to prevent 'his woman' from mating with another!

Who've you been listening to again? Ask your informant how they know
this and why it isn't the male having to carry the stick because the
female
doesn't want him chasing after other females?

As the sexes are identical in plumage, it's almost impossible to say
which is which when they're in flight, and pretty difficult even if you
see them side by side on the nest, when the male is very slightly the
larger. Of course, if you happen to see them copulate, then the male is
the one on top!

I might just notice that. Being a female and all..... ;-)

In fact, studies have shown that it is the male which usually does most
of the stick collecting while the female does more of the actual
building of the nest. And it is often normal for the female to stand
guard over the nest to stop neighbours stealing twigs from it while the
male is away twig collecting.

I hope I haven't misquoted someone but I asked on the ornithology group
quite a while back and I thought I correctly remembered that as the answer I
got. I watch rooks and jackdaws wandering around the lawn in the very early
morning hours, squabbling over the food and behaving like yobs generally but
I can't pretend to tell males from females!

--
Sacha
www.hillhousenursery.co.uk