Factors determining timing and success of breeding? |
In captivity, Barn Owls
breed prolifically, often having several broods throughout the year.
That is why, years back, breeders would be forever releasing young
owls into the wild, a practice that has dwindled after legal
restraints on release of captive-bred birds were imposed.
Could it be that,
underlying and determining the breeding behaviour of wild
Barn Owls is the same urge to prolific breeding? Thwarted constantly,
of course, by such factors as inability to come into breeding
condition because of
inclement weather that
makes hunting difficult or lack of sufficient prey when the vole
population crashes.
In the season just
gone, a lot of pairs formed but didn't breed at the usual time, and
then, there was a spate of late first clutches, probably because the
vole population had increased in the summer (as often happens) and
the breeding imperative kicked in again.
The trouble is that the
later in the year the hatch, the less likely it is that the young will
make it to fledging. Result: lots of failures, or at best just one or
two chicks getting off.
It is important,
though, not to make bald statements about good years and bad years,
as the situation can vary considerably in different parts of the
country. The West Country has a bad season, Suffolk, it seems,
doesn't do too badly. Central Cambs and other parts ofthe Fens are
disappointing, the Peterborough area has a fairly normal breeding
season.
And now, as we approach
winter, it is tempting to start another round of theorising and
predicting: a poor breeding season means fewer birds means less
competition for the food during the winter. Well, maybe. A mild
winter favours the owls. Well maybe, but does it favour the rodents
and inverterbrates? And is the converse true? How do owls fare in a
hard winter? And does the timing of cold snaps, wet spells, strong
winds play a role?
About the only
prediction that's reliable is, to paraphrase a famous saying of a
southern Baptist Minister: “things ain't what we want 'em to be,
and things ain't what they're gonna be, but they shure ain't what
they wuz.” I find that mildly comforting, even though it is
deeply meaningless. Anyway, it's as near as you will get to a
prediction from me.
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