Outdoors: At home in the city or on the coast, the gull is one successful scavenger

Published on Monday 23 January 2012 00:00

THE NEXT time you pass a playing field or park and see a flock of feeding herring gulls, it’s worth stopping for a moment to observe their behaviour.

If scrutinised closely, it is usually possible to see some of the gulls engaged in the rather bizarre act of rapidly stamping their feet up and down, almost as if running on the spot.

It’s not some gull version of Riverdance, but a rather clever feeding tactic, for the vibrations caused by the rhythmic patting of the feet mimic the vibrations of raindrops, thus causing earthworms to come to the surface, only to be then snapped up by the hungry bird.

Such behaviour characterises the very soul of the herring gull, which is hallmarked by opportunism and an ability to be at home in a variety of environments. It is a bird equally content following a trawler at sea, as turning over the surface of an inland rubbish tip or scavenging the contents of discarded fast food containers on the streets of our cities on a Saturday night.

The herring gull is a bit of a glutton, knowing that if it doesn’t bolt its food down quickly, there is every chance it will be the victim of piracy from another bird. A small plaice accidentally discarded on the fish market quayside presents no problem at all, with a gull being able to expand its gape to such an extent as to swallow the flatfish whole.

For much of the 20th century the herring gull was one of our most successful birds, with numbers increasing rapidly, but in more recent times the population has fallen for reasons that are still not fully understood. It is thought that poisoning from botulism at rubbish tips may be one factor, with the decline in the fishing fleet and the loss of attendant easy pickings in the form of offal and discards another. Urban nesting pairs seem to be faring better than coastal colonies, so changes in marine ecology and fishing practices may well be the driving factor in some areas.

Certainly, there will be few who will lament such a decline. When numbers were at their peak, predation by herring gulls was often blamed for the lack of success of breeding tern colonies, and in some coastal towns they had reached pest proportions with their droppings fouling the streets, combined with the added irritation of aggressive adults causing havoc among shoppers during the breeding season. I recall in Aberdeen in the late 1980s, some of the streets being inundated with scuttling young gulls that had just dropped down from their rooftop nests, but had yet to master the art of flying.

Some of our other gull species are in decline too. The black-headed gull is a rather dainty bird that is often seen floating on slender wings in the wake of a tractor plough. It breeds in inland colonies on the marshy fringes of lochs, but many of its former breeding haunts have been abandoned. Similarly, numbers of the inappropriately named common gull have also fallen. In 1988 one colony in the Coreen Hills in north-east Scotland contained more than 24,000 pairs, but ten years later the colony had gone. Both species are rather fickle and there is some evidence suggesting that fluxes in the location and size of colonies may be part of their natural cycle.

There is one gull, however, that outshines all others when it comes to sheer presence and power. It is the great black-backed gull, which is the scarcest of our regular breeding species. One can never fail to admire the opportunistic nature of gulls, and this is surely no better illustrated than with the great black-backed gulls that haunt the tributaries of the River Dee in Aberdeenshire during early winter. They are on the scavenge for the bodies of spent salmon (kelts) that have just spawned, and the sight of a great black-back swooping between the alders lining a gushing spate river is as great a natural spectacle as any.

Comments

There are 1 comments to this article

Order by:

• Newest first
• |
• Oldest first

Page 1 of 1

• 1
• Show all

1

Peripatetic Pensioner

Monday, January 23, 2012 at 01:19 AM

Give all pensioners free blowpipes and poison darts for use on bl@@dy herring and greater and lesser black back gulls in urban areas.

• Report Unsuitable

Order by:

• Newest first
• |
• Oldest first

Page 1 of 1

• 1
• Show all

Logged in as:

Comment here. Start typing your comment here:

Post comment

Please adhere to our Community guidelines

Your view

Please sign in to be able to comment on this story.