Northern Ireland's Priority Species

Larus ridibundus – black-headed gull

 
Larus ridibundus

Larus ridibundus L.
Family: Laridae

One of our most familiar species, the black-headed gull can be seen in virtually any habitat including city centres. Like many species of gull it is an expert scavenger, taking advantage of easy options and handouts. The bird is poorly named as its hood is in fact chocolate brown and totally absent in winter! When breeding it is highly colonial, these colonies being associated closely with coastal islands and large inland waterbodies.

In brief

  • A gregarious small gull with a brown hood in spring and summer and greyish ‘earphones’ in winter
  • It is a very widespread species which can be encountered almost anywhere but especially close to water
  • Around 10,000 pairs nest in Northern Ireland but wintering numbers are considerably higher
  • The largest breeding colonies are in Lough Neagh and Strangford Lough
  • It is a Species of Conservation Concern in the UK and Ireland because of recent declines in its breeding population.

Species description
The black-headed gull is the smallest gull likely to be encountered commonly in Northern Ireland. In breeding plumage this gull is distinguished from all others by its chocolate brown hood which does not extend onto the nape, black and white patterned wing tips, red legs and red slender bill. In winter, the brown hood is replaced by grey smudges somewhat resembling earphones. Immature birds resemble winter adults but with, depending on age, varying amounts of brown feathers in the wings. Very young birds exhibit much more brown in the plumage and can cause identification problems for the unwary.

Life cycle
The black-headed gull nests colonially, sometimes in large colonies of over 1,000 pairs. The nests are an untidy pile of readily available material such as seaweed or straw, a slight depression in the top of the structure hosts the four or five eggs. The egg colour varies widely but typical eggs are olive-brown with large erratic black or dark blotches and fine squiggles. The eggs hatch in around 24 days and the young fledge in a further five to six weeks. Pairs raise only one brood annually but will often re-lay if the first clutch is lost. In winter large numbers of immigrants arrive from northern Europe to augment our resident population. Wintering birds are also extremely gregarious and will move considerable distances in search of easily available food. Several thousand birds can be found scavenging on rubbish dumps or feeding at sewage outfalls.

Similar species
All similar species are rare in Northern Ireland, the Mediterranean gull (Larus melanocephalus) and the little gull (Larus minutus) being the most common and the most similar. All small gulls with a brown hood encountered in Northern Ireland will be black-headed gulls; the similar species mentioned all have blackish hoods. Depending on age, gull plumages vary considerably within any species and this must be considered with any identification as must the loss of the hood in winter. For a full explanation of gull ageing and identification refer to Literature and Links below.

How to see this species
This species is easily observed anywhere and at any time of the year. Large flocks often follow ’the plough’ in farmland, feed in playing fields or scavenge at rubbish dumps. In fact it can be found just about anywhere food (such as scraps and rubbish) is available.

Current status
As a breeding bird the largest colonies are found in Strangford Lough, Lough Neagh and Larne Lough. Seabird 2000 estimated a Northern Ireland population of a little over 10,000 pairs, of which just over 4,000 were coastal. This represents a significant decline from the previous survey in 1985-88 when over 38,000 pairs were counted. Most of the losses relate to Lough Neagh, but there was also decline at sites in County Down. Only the Lough Erne colonies in Fermanagh have increased during this period. The black-headed gull is protected under the Wildlife(NI) Order 1985.

Why is this species a priority in Northern Ireland?

  • The species is listed as Amber in both Irish and UK Birds of Conservation Concern as its breeding population has undergone a moderate decline in the past 25 years and more than 50 per cent is concentrated in ten or fewer sites.

Threats/Causes of decline
The reason for the decline at some Northern Ireland breeding sites is unclear. Predation of eggs by mammals, crows and other gulls is a known problem. Habitat changes, egg collection and destruction could be an issue on some sites.

Conservation of this species

Current action

  • Some breeding sites for this species have been designated as ASSI by EHS
  • Gull numbers were systematically surveyed in 1998-2002 as part of the Seabird 2000 project.

Proposed objectives/actions

  • The status of the black-headed gull will be surveyed and monitored and appropriate conservation action undertaken if required.

What you can do

  • Participate in any organised gull counts (Wintering Gull surveys are organised by BTO on a ten-year cycle)
  • Report any isolated breeding colonies that you think may have been overlooked on Northern Ireland Birdwatchers’ Association, Flightline. Tel: 028 9146 7408.

Further information

Links
Find further information on the species at:

http://www.birdguides.com/html/vidlib/species/Larus_ridibundus.htm

http://www.rspb.org.uk/birds/guide/b/blackheadedgull/index.asp

http://www.arkive.org/species/ARK/birds/Larus_ridibundus/

Designated areas

Literature
Burton, N.H.K., Musgrove, A.J., Rehfisch, M.M., Sutcliffe, A. and Waters, R. (2003). Numbers of wintering gulls in the United Kingdom, Channel Islands and Isle of Man: a review of the 1993 and previous Winter Gull Roost Surveys. British Birds 96: 376-401.

Mitchell, I.P., Newton, S.F., Ratcliffe, N. and Dunn, T.E. (2004). Seabird Populations of Britain and Ireland. T. and A.D. Poyser, London.

Olsen, K.M. and Larsson, H. (2004). Gulls of Europe, Asia and North America. Christopher Helm.

Svensson, L., Mullarney, K., Zetterstrom, D. and Grant, P.J. (1999). Collins Bird Guide. Harper Collins.

Text written by:
Allen & Mellon Environmental Ltd.