"Brent Geese are now using the inner parts of Dublin Port on
a regular basis. As the winter
progresses, their natural food resources
such as eelgrass and green seaweeds become scarcer on the mud and sandflats
throughout the bay. The geese seem to have been forced
to seek out other feeding areas including golf links, sports pitches and public
parks with over a hundred such sites now used around the city. A recent development has been the tendency of
some geese to favour feeding on spilled agricultural products on the quaysides in Dublin Port.
.JPG) |
| Feeding flock by the quayside - Richard Nairn |
They swim on the River Liffey
or in the Alexandra Basin (a deep mooring area for large ships within the port) until any disturbance has passed and then fly up onto
the quays where they feed intensively on maize and soya meal among large flocks
of pigeons and smaller numbers of gulls. So far as we are aware this behaviour has not been recorded anywhere else in their range which
includes sites in Canada, Iceland and throughout Ireland. I have been monitoring these geese closely over the last
few winters and peaks of up to 450 geese using this source of
food have been recorded.
.JPG) |
| Brent Geese next to Alexandria Basin - Richard Nairn |
Among them are some colour-ringed
geese and the large numbered codes on these rings show that a core group of up
to ten individual birds are using the Port on a regular basis, including over
several winters. This suggests that some
geese have learned to exploit this food and others then follow them in to share the spoils.
.JPG) |
| Ringed Brent Goose - Richard Nairn |
You can follow the fortunes of the geese on the blog posts
of the Irish Brent Goose Research Group at http://irishbrentgoose.blogspot.co.uk/."
There are so many cases, globally, where birds turn to high-energy food where available; my first association goes to the wintering ruffs of the Sahel area. But there is an even closer example: In October, when the sugar-beets are harvested in Skåne, S. Sweden, barnacle geese collect by thousands to devour the sweet-tasting leftovers (they used to be given to the milk-cows earlier, but we have so few cows today). The ensuing fattening may be one reason for the widespread wintering of barnacle geese in South Sweden in later years.
ReplyDeleteAs early as 1986, Vitousek, Ehrlich, Ehrlich & Watson wrote in Bioscience: We estimate that organic material equivalent to about 40 % of present net primary production in terrestrial ecosystems is being co-opted by human beings each year. That amount is well over 50 % today, and increasing all the time, so where is animal evolution to head?
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