24
BIRDS IN WINTER
The 1986 winter with its severe frosts and snow
reminded us that some birds do survive whilst
others have a very difficult time. The
1962—63 winter was one of the coldest for a
number of years. Afterwards birds such as
Wrens, Song Thrushes, Green—Woodpeckers,
Lapwings, Pied Wagtails and Moorhens all
suffered a reduction in population. It is too
early yet to predict the effects of the recent
severe winter.
Populations of birds are affected mainly
because of lack of food and water. Some birds
that feed on the ground, such as Song Thrushes,
Blackbirds and Skylark, find it hard or even
impossible to get their food in deep snow; or
even if the ground is hard with frost. Some-
times if the snow lasts for a number of days or
weeks migrations take place. This is
certainly true of Redwings and Fieldfares
arriving in this country from November
onwards. Skylarks, Lapwings and other birds
may even leave to find food elsewhere, e.g.
Ireland where severe winters are not so common.
In woodlands the snow is often not so deep —
but ice can stop birds feeding. This is due
to rain falling onto twigs and forming a
coating on them which freezes. Wrens, Tits
and Goldcrests then attempt to feed on the
ground — it then becomes a case of survival of
the fittest. Acrobatic birds, such as Tits,
are sometimes able to find food on the unfrozen
underside of leaves or twigs by hanging upside
down.