Population Trends of Gulls and Arctic Terns Nesting in the Belcher Islands, Nunavut

Abstract

ABSTRACT. Little information exists on the population trends of gulls and terns nesting in the Arctic. In 1997, we surveyed the number of glaucous gull (Larus hyperboreus), herring gull (Larus argentatus), and arctic tern (Sterna paradisaea) nests on the Belcher Islands (56˚00' -57˚30'N, 79˚30' -80˚00'W). We compared our results with the mean number of nests per island counted in the Belcher Islands in the late 1980s using the same survey methods. The mean number of gull nests per island had declined in all five archipelagos surveyed, and the decline was significant in three regions. The number of arctic tern nests had also declined in all three regions where they were originally present, although this decline was significant in only one region. The causes of these apparent declines are unknown. Adult mortality or emigration of gulls from the area may have occurred in response to changes in polynya formation during recent winters, which restricted access to marine food sources. Reproductive success of gulls may also be low in response to the recent 75% decline in common eiders nesting in the Belcher Islands. Eider eggs and ducklings are an important food source for gulls during the breeding season. The decline of nesting arctic terns may reflect either winter mortality of tern populations caused by unknown factors or emigration out of the Belcher Islands in response to regional egging and disturbance by local residents.Key words: arctic tern, Sterna paradisaea, Belcher Islands, glaucous gull, Larus hyperboreus, herring gull, Larus argentatus, polynyas, population trends RÉSUMÉ. Il existe peu de renseignements sur les tendances dans les changements de population des mouettes et sternes qui nichent dans l'Arctique. En 1997, on a établi un relevé des nids du goéland bourgmestre (Larus hyperboreus), du goéland argenté (Larus argentatus) et de la sterne arctique (Sterna paradisaea) dans les îles Belcher (56˚ 00' -57˚ 30' de latit. N., 79˚ 30' -80˚ 00' de longit. O.). Nous avons comparé nos résultats avec le nombre moyen de nids par île comptés dans les îles Belcher à la fin des années 1980, en employant les mêmes méthodes de relevés. Le nombre moyen de nids de goélands par île a baissé dans les cinq archipels étudiés, et la baisse s'est révélée importante dans trois régions. Le nombre de nids de sternes arctiques avait également baissé dans les trois régions où elles étaient présentes à l'origine, bien que ce déclin ne fût important que dans une seule région. On ne connaît pas les causes de ces baisses apparentes. La mortalité adulte ou l'émigration des goélands de cette zone aurait pu se produire en réponse aux changements survenus dans la formation de la polynie au cours des derniers hivers -changements qui auraient limité l'accès aux aliments venant de la mer. Le succès de reproduction du goéland pourrait aussi être bas suite au déclin récent de 75 p. cent chez l'eider à duvet qui niche dans les îles Belcher. Les oeufs d'eider et les oisons constituent une importante source alimentaire pour les goélands durant la ...

Assessing regional populations of ground-nesting marine birds in the Canadian High Arctic

“…While numbers of terns have fluctuated at our main site (Nasaruvaalik Island), regionally we found a pattern of decline, consistent with other reports we have heard anecdotally from local hunters in the High Arctic and along western Hudson Bay (M. Mallory, unpubl. data), and from limited results elsewhere in Nunavut (e.g., Gilchrist & Robertson 1999).…”

Observations of the summer birds of Tukarak Island (Belcher Islands, Nunavut), Nastapoka Islands (Nunavut), and Lac Guillaume-Delisle (northern Quebec)

“…arctic Tern populations declined between the 1980s and 1997 in the three northern regions (Sleeper, Split, and Laddie Islands) of the Belcher Islands (Gilchrist and robertson 1999). Only 19 of the 431 islets in that region had nesting terns in 1997.…”

“…This decline is attributed either to winter mortality or to emigration out of the Belcher Islands as a response to egging or disturbance by residents of Sanikiluaq, the only village on the islands. The tern surveys, summarized by Gilchrist and robertson (1999), were not made on Tukarak Island, presumably because arctic Terns are not known to nest on this island.…”

“…More recently, information on Common eiders was summarized by abraham and Finney (1986) and by robertson and Gilchrist (1998). arctic Tern and gull population trends on the Belcher Islands were described by Gilchrist and robertson (1999). a checklist of the bird life of Nunavut (richards and White 2008) is based on recent sightings from throughout this vast territory.…”

Common Eider and large gull and nesting associations in coastal Labrador

“…Compared to the large colonies in temperate nesting areas, in northern regions, both eiders and large gulls generally nest in relatively small and widespread colonies (Robertson and Gilchrist 1998;Gilchrist and Robertson 1999;Chaulk 2012;Robertson and Chaulk 2016). Additionally, nesting colonies are much more dynamic, with numerous islands being abandoned and new islands colonized each year by both gulls and eiders (Chaulk et al 2006;Robertson and Chaulk 2016), possibly due the dynamics of snow melt and sea ice (Parker and Mehlum 1991;Chaulk et al 2007).…”