PREDATORY GOLLS

Evening Star, Issue 22457, 30 September 1936, Page 7

PREDATORY GOLLS

GANGSTERS OF THE SEA DAMAGE TO FISHERIES ? EVIDENCE SIRED The complaints made of injury done by gulls to the salmon and trout fisheries recall memories of 30 years ago (writes the zoological correspondent of the ‘Manchester Guardian’). We are not told what species of gull is accused, but it is fairly safe to assume that the object of this attack is the comparatively small black-headed gull, otherwise known, bn account of its cachinnating cry, as the laughing gull. An appeal is to be made to the Cumberland County Council to remove protection from presumably this species of gull, though possibly the herring gull may also be involved. I wonder whether the county council is aware, or will be reminded, that 30 years ago their predecessors in office caused a searching inquiry to be made into the feeding habits of the blackheaded gull, and that the case against it was to all intents and purposes dismissed. A report of the inquiry, which lasted for more than a year, was published in Carlisle by Messrs James Beatty and Son in 1907. It is an interesting document, for it records the opinions—expressed in reply to a widelycirculated questionnaire—of 34 of the best known ornithologistst of the day, as well as of a number of farmers, fishermen, and gamekeepers. It also records the results of the examination of the stomachs of a hundred black-headed gulls. “Of the 36 birds obtained on the Eden between Carlisle and Rockcliffe,” says the report, “ only seven contained traces of fish, none of which could be clearly identified as salmonidse.” And again; “ Although we have had the black-headed gull under almost daily observation for several years . . . we have never detected the bird in the act of catching fish.” As gulls, though capable of immersing themselves to a modest depth, are not competent divers, they could only have caught fish in fairly shallow water. OMNIVOROUS EATERS. The report made to the county council is in general borne out by the results of investigations since’ carried out by competent naturalists at different times and places. It would be idle to suggest that the black-headed gull eats no fish. It would be equally idle to pretend that there is anything edible that any gull will not eat if it comes its way. Speaking generally, gulls are omnivorous, and, in varying degrees, they are robbers and scavengers. In the latter capacity they exercise, a useful function, particularly in fishing ports, where they clear up the offals of the fishing industry. It happens, however, that the blackheaded gull is less of a scavenger and more of a beneficent hunter than most of the gulls, and hardly, if at all, a robber. These gulls breed inland, and it is mainly inland that they find their food. They devour large numbers of earthworms, wireworms, leatherjackets, and other harmful as well as harmless or even beneficial grubs in great variety. In pursuit of such food they will, when ploughing is in progress, follow the plough in numbers, like rooks. Sometimes they eat grain, though their depredations in_ this respect do not appear to be serious, and they hawk various flies on the wing. They are commended for eating the daddy-longlegs; but they are also very fond or the larger acquatic flies, and this has been brought up against them. When there is a good rise oF Mayflies or March-browns on a river these gulls frequent they devour them in great quantities, and they seem to have a P uncanny prescience, so that they assemble in force just before the rise begins. It cannot be denied that in this respect they compete with the fish for food. But one hears mst the same complaint made against swallows, martins, and swifts who hawk the ephemeridas of the chalk streams: yet no one has suggested that they should be destroyed on this account. Nature is very lavish, and there is no reason to think that there are not enough fl tes to go round now as for centuries past. STRIKING A BALANCE. In studying the economics of ornithology one has to strike a balance. The naturalists and others to whom inquiries were addressed on behalf of the Cumberland County Council in 1906 were asked to say whether, from their observations, they thought the black-headed gull was harmful or beneficial to farming and to fishing. Of the 34 naturalists only one suggested that it was harmful to farming, and 12 reckoned it to. be beneficial. Only four of them thought, it was harmful to fishing. A majority of the farmers regarded it as a benefactor, and two out of three gamekeepers thought it did no harm to fishing The examination of stomachs can-led out by the reporters was clearly in favour of the bird as a friend of the farmer and not a serious enemy to the fisherman. When we are feeding the black-headed gulls that crowd to the lakes in the parks in London and elsewhere every winter we have no reason to feel that our chanty is misplaced. , . ~ When we come to the herring gulls and the greater black-backed gulls, two of the best-known of the other species, the case is not so clear, r ish, including crustaceans and molluscs, certainly play a considerable part in their diet. But by no means all the fish they eat is of kinds that, man uses, and a great deal of what they take is the refuse of the fish markets. Certainly herring gulls follow the shoals of herring and manage to take a toll of them when they' swim close to the surface. For they can precipitate themselves into the water to some depth and snatch up swimming fish. But, on the whole, they prefer to scavenge in the ports or to hang about the fishing vessels, to swoop on dead or crippled fish that drop from the nets or those that are discarded and thrown overboard. ANYTHING WELCOME. The chief preoccupation of every gull seems to be an easy meal without special regard to its quality. , They fly without effort. Everybody is familiar with the attendant company of gulls that follows every ship at sea. They are there to pick up the refuse thrown overboard. Anything they can digest is welcome. In Aberdeen, where the Aberdonians invent the many apocryphal stories of their own meanness, they will tell you that you can always recognise an Aberdonian ship at sea because no gulls follow it! Herring gulls, like the Mack-headed gulls, may be found in numbers inland, and they, too, confer some benefit on farmers by destroying harmful grubs and insects. But they, unlike the black-headed gulls, are chiefly buds of the open sea and of the ports. They are also cannibals, robbing the nests of other birds, especially guillemots and cormorants. By so doing they help to keep in bounds the numbers of these regular and most skilful hunters of fish. Thus their social

crimes may contribute to the wellbeing of the fishing community. The most audacious criminal of all is the greater black-headed gull. Like the rest of the gulls, he is omnivorous. He is not above scavenging and loves carrion. But he is the great big bully of the sea-birds. No nesting colony, not even those of the gannets, is safe from his raids on eggs and young. He prefers larger prey, an injured bird or hare, or a weakly, unguarded lamb. With his great, sharp, powerful bill he rips and devours them as swiftly as a vulture. He is, and rightly so. an outlaw everywhere—but what a handsome outlaw!