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Sand martins in drains |
29.04.2000 |
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Ó
Michael Woods |
When I first saw the flock of sand
martins circling over the Great Ouse and dashing after
insects a few weeks ago in late March, they must have just
returned from Africa. Their presence was a tangible sign
that winter was losing its grip. The pleasure of spotting
sand martins is further enhanced because it is one of our
bird species that has suffered a massive slump in numbers.
This was the result of two catastrophic winter mortalities
in the 1960s and 1980s, when sand martins were hit by
drought in the Sahel region of Africa.
I was watching these sand martins from
the pictureesque 15th century bridge that was once the main
entrance to St Ives and was wondering where I should start
searching for their nest burrows. The colonies are normally
in the sandy banks of rivers and, increasingly, sand and
gravel pits. You can imagine my surprise, then, when one of
the martins flew into a 4-inch metal drainpipe set into the
side of the bridge. At first I thought I might have been
mistaken but I soon found there was a regular traffic in and
out of the drain.
Since then I have learned that sand martins regularly nest
in the drains of the bridge and the adjoining riverside
embankment. The drains once carried rainwater from the
carriageways but resurfacing has blocked them off.
Custom-built nest burrows must save the martins a couple of
weeks' hard labour and will not have the danger of
collapsing, but I never thought sand martins would qualify
as urban birds!
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