The final bird of the three species that regularly nest on Rathfarnham Castle is the herring gull or the European herring gull as we should properly call it (there is an American herring gull) the quintessential “seagull” and the backdrop to trips to the seaside. However, the herring gull is as happy inland as it is by the coast as is shown by the fact that apart from its association with Rathfarnham Castle, it is seen every day in busy town and city centres. In recent years this readiness of the herring gull to live in close proximity of people has been a source of conflict and sensationalist headlines on the front of newspapers, portraying these elegant and intelligent birds as marauding, malevolent creatures that are out of control, over populated and a pest that needs to be violently controlled. That is a myth of our own making; the illusion being created by the fact that these human created environmental factors have led to an increased density of gulls in urban centres; some of these “seagulls” spend all of their time inland and never even see the sea, (in spite of the folklore suggesting that seeing gulls inland means it is stormy at sea,) such is the attraction of human, urban settlements. A combination of botulism (which the use of the black, plastic, bin liner for rubbish storage seems to have helped create,) increased mammalian predation, reduction in fish discards from the fishing industry and improved efficiency at refuse dumps have all contributed to a huge decline in herring gull populations around the coasts of Britain and Ireland. Since 1970 the number of birds in herring gull colonies have dropped by fifty per cent in the UK and sixty per cent in Ireland and is classified as “red listed” in both countries, meaning that the species is of conservation concern requiring urgent action. In urban areas the herring gull finds conditions to its liking in the form of buildings for its nesting sites and easy pickings from a combination of food that we might choose to give it and from what we discard and in particular from our love of fast food and what we drop or throw away. However, research from the United States suggests that perhaps as with human populations who moved from country to town during the Industrial Revolution, there is a cost involved with the benefits of urbanisation. The greater abundance of food does not guarantee increased nutrition and these studies show that fewer eggs were laid by urban gulls, fewer chicks fledged and adults lived shorter lives than truly wild gulls. In addition, those birds living off food from human rubbish sites laid fewer eggs, with fewer chicks hatching from those eggs and fewer chicks fledged from those that did hatch. Therefore, whilst recognising that there might be genuine problems where herring gulls and humans intersect, it perhaps pays us to be tolerant of them and recognise our part in their predicament.
What’s In a Name?
The English word “gull” is probably derived from a Brythonic Celtic word, possibly the Cornish guilan, the Welsh gwylan or the Breton goelann. It has been suggested that Gwylan means wail, in which case the Brythonic word reflects the sound of the breeding call of the bird – the classic seaside sound. In the Anglo-Saxon poem The Seafarer the word “maew” or “mew” is used to refer to the bird, possibly related to the mewing sound of its call. This word may predate Anglo-Saxon as a language and variations on it can still be found in lowland Scots and mew gull is also the North American term for the common gull and is also found in the fulmar or “foul mew.” This comes from the old Norse and refers to a the birds’ defence strategy of spewing a smelly, sticky oil at intruders to its nesting sites. References to mew also occur in the Dutch and German names for the herring gull. Herring in the English name presumably refers to its habit of following fishing trawlers. Scientifically it is classified as larus argentatus. Larus comes from the Greek for “gull” and argentatus from the Latin for silver. Indeed, in Dutch and German the name literally means “silver mew” and in French “silver gull,” a reference here not to the birds call or feeding habits but to the colour of its wings, which, incidentally is assumed to offer it camouflage against the colour of the sea when viewed from above. The Irish term for herring gull, Faoileán scadán, is a direct translation.
As well as the silver back of herring gulls, the white plumage of the underside of seabirds such as gulls and gannets, for instance, makes perfect sense from the perspective of camouflage. These birds dive into the sea to catch prey and so need to avoid being seen from beneath the waves; other birds such as cormorants and guillemots pursue their prey under water and are in less need of an invisibility cloak. The black wing tips of herring gulls and many white seabirds need an explanation though. The black pigment in the feathers is produced by the substance melanin and has the effect of strengthening the wing tip from wear and tear. The wing tips suffer from the greatest stress in flight, especially for birds that glide and soar so it is vital to protect these. Another idea is that the dark tips allow a temperature differential to be established between the white portion of the wing, nearest the bird’s body and the black tip; this, in turn produces convection currents above the wing making the flight more efficient and so saving the bird vital energy.
Nesting and breeding
In their truly wild state herring gulls nest on steep grassy slopes on cliffs or rocky ledges, hence cliff like buildings such as Rathfarnham Castle make ideal sites for urban and suburban gulls. The nest itself is a shallow and untidy collection of vegetation of various kinds and is sometimes lined with wool. At the end of April or the beginning of May the nesting pair will lay one clutch of usually three eggs. The adults will occupy the nest site during the mid winter months and the territory will usually amount to no more than about five square metres although, for architectural reasons, the space may be larger on buildings. The chicks are quick to develop but take a long time to grow up; they are regularly left for long periods when just a few days old to allow the adults to go foraging for food; they won’t be fully adult for another three years. After about 5-6 weeks the young are able fly and often join other young gulls and learn foraging strategies from one another. They can still be seen begging from adults however and this begging behaviour can also be seen between the adults during courtship, when the female will simulate this behaviour by “begging” from the male, strengthening the bond. In the mid twentieth century research discovered that herring gulls, in common with many other animal species, respond to exaggerated stimuli. For instance, the larger and more highly coloured the egg the higher its chances of being incubated, presumably reflecting the quality of the egg and the viability of the chick inside. Similarly, unless the chicks peck at the red, pigmented spot on the parents beak, they will not be fed. Again, presumably, this reflects the vitality of the chick. Weaker eggs and weaker chicks don’t survive; ruthless but efficient.
Herring gulls are long lived birds; indeed, the oldest recorded was 49 and as is common among long lived birds they pair for life and, as has been said, the youngsters take a long time to reach maturity. In the meantime their plumage remains a mottled, brown and white, becoming more white as the years progress. Why should this be? Most bird fledglings don’t assume adult plumage until they are old enough to breed. For instance, the familiar, garden robin is a mottle brown until the autumn of its first year. The assumption is that this protects it from predators and also stops it from being attacked by other, adult robins and this is also seemingly the case for the herring gull. Young gulls spend far more time inland than their do their parents and don’t travel so far out to sea and so are possibly under greater threat from predators such as eagles and skuas.
Behaviour
Although they breed in pairs and have small territories, herring gulls, in common with other gulls are gregarious. They will often gather together in groups in the air or on beaches or flat, grassy areas to forage or simply to rest with safety in numbers in mind, although they will frequently squabble with one another. In the winter inland gulls will roost by lakes and reservoirs for safety at night and a real pleasure is to see them flying in a ‘V’ formation, sometimes circling as they soar, back to those roosts from their feeding grounds an hour or so before dusk. In addition to this daily, winter “migratory” behaviour, herring gulls will also genuinely migrate further distances. Many gulls seen in Britain and Ireland during the winter have arrived here from the colder climate of eastern Europe, Russia and Scandinavia. However, in general herring gulls aren’t great travellers and it is the younger and therefore lower status birds who may be forced to make the longer journeys. Herring gulls are normally “site faithful,” in other words they return to the same nesting site each year; in fact a gull that was ringed as a chick at a site in England in June 1978, was found dead at the same site 31 years later in June 2009! Herring gulls have a wide dietary taste, hence their love of human waste and fast food. It may also be that, in common with other gulls, they could possibly be considered raptors – birds of prey; they aren’t but there’s certainly a case to be made. Obviously gulls are associated with eating fish but few gulls are actually excellent fishermen like the kittiwake, for instance, but Herring and many other large gulls are happy to exploit other creatures, especially the chicks of other gulls in the breeding season and sometimes a few “rogue” gulls in a colony will even eat their neighbours chicks, indeed, the writer of this piece has witnessed two herring gulls ganging up on an adult pigeon, in the air, outside of a shopping centre!They are indeed, powerful and voracious birds. They are also intelligent and other feeding strategies involve dropping shellfish or snails from a height and following them down to the ground and eating their smashed remains and some herring gulls have been observed using pieces of bread to lure goldfish from ponds! Another strategy is to drum their feet on the ground in order to encourage earthworms to the surface. It seems that the worms either think that the sound is rain or that it is mole hunting behaviour and so slide to the surface to escape only to be consumed by the gull! They are also not immune to a bit of piracy, frequently pursuing other herring gulls and assorted species “encouraging” them to disgorge whatever food they might happen to be carrying.
What Next?
In spite of appearances the herring gull in Ireland and Britain is in trouble. It needs tolerance, understanding and a less sensationalist press. If conditions do improve for this magnificent and intelligent gull, that perhaps, we are over familiar with, it has been suggested that the urban breeding population, which tends to be more successful, could serve as the basis for a rebuilding of the population in the wider environment. This bird, the European herring gull, the “seagull” that for many of us, was the sound of childhood summers.