20-08-03 01:25, Miguel Carrasquer wrote:
> On the subject of ornithology (off topic): since a couple of years, the
> city where I live (Hilversum, Holland) has been completely taken over by
> rooks or ravens (I'm not sure what they are: black loud corvids, in any
> case). There's thousands of them, everywhere. Worse (lugete, o Veneres
> Cupidinesque), all the little musjes (pardalets, wróbelki, sparrows) have
> disappeared. (My cat misses them too, for different reasons). How wide-
> spread is this phenomenon?
They are certainly rooks. Rooks are colonial and like to claim city
parks as their rookeries. Ravens, which are much bigger and to a lesser
extent synanthropic, live in small groups and prefer the country. To be
sure, most corvids are highly intelligent and adaptable; I've seen
ravens lunching on discarded sandwiches on the Santa Monica beach, in
perfect harmony with crowds of people. They used to be rare or at least
seclusive in Poland a few decades ago, but are now expanding into
suburban areas; I see them regularly on the outskirts of Poznan. Not
thousands of them, however, but from one to half a dozen at a time.
Sparrows are becoming rare in many European cities for reasons that are
not entirely clear. Corvids (especially magpies) and cats have been
blamed for the decline of the sparrow, but it seems other factors are
far more important:
http://www.xs4all.nl/~amvdpoel/Paper2.html
Piotr