At-sea observations of the spring migration and pair bonding of ivory gulls (Pagophila eburnea) around Svalbard and East Greenland

Abstract

Because of logistical constraints little previous information exists on ivory gulls (Pagophila eburnea) in the waters around Svalbard and the east coast of Greenland in late winter/early spring. The Swedish Arctic Ocean 2002 expedition investigated these areas at that time of year and in this paper I report on the observations of ivory gulls made during the expedition. The ivory gull was essentially absent from open waters but was the most common seabird in areas with pack ice, showing behavioural differences depending on local conditions. Generally, the number of ivory gulls was low when there was little plankton in the water. Ivory gulls followed the ship depending on the availability of food items in the wake and also depending on competition from other species, particularly glaucous gulls (Larus hyperboreus). Although ivory gulls were present in most of Fram Strait and the northern part of the East Greenland Current during 6 and 19 May, sightings were few and correlated to the amount of plankton in the water. Aggregations of several hundred were seen on the ice where copulation and other social interaction took place. A previously undescribed pair bonding behaviour during which females seemed to select between two competing males was observed north of Svalbard on 30 April–1 May. Off Scoresby Sound on 25 May, more than 700 birds were seen migrating north, while farther south along the Greenland coast on 30 May there was little indication of migration although many ivory gulls were seen

Observations of Heterospecific Courtship Behaviour in an Isolated Population of Ross’s Gulls (<i>Rhodostethia rosea</i>)

“…In this context, courtship behaviours directed towards unsuitable mates (such as heterospecific partners) may still increase the quality or quantity of an individual's mating opportunities by reducing subsequent intrasexual conflict once a suitable mate is attracted. Male-male forced copulation, for example, has been well documented in several monogamous Arctic birds, including Common Murres (Uria aalge) (Birkhead et al, 1985) and Ivory Gulls (Mallory et al, 2008;Kylin, 2011), and it has been correlated with increased extra-pair copulations in dominant males in at least one species, the Razorbill (Alca torda) (Wagner, 1992(Wagner, , 1996. We speculate that the heterospecific courtship displays of Ross's Gulls may also function to help establish dominance hierarchies, but additional data on marked birds are clearly required to address this possibility.…”