Non-breeding movements of Black-legged Kittiwakes Rissa tridactyla from a North Sea urban colony
* Correspondence author. Email: firstname.lastname@example.org
42 Linden Close, Aldeburgh, Suffolk IP15 5JL, UK.
Early indications of the extensive North Atlantic non-breeding period range of Black-legged Kittiwakes Rissa tridactyla (hereafter Kittiwakes) have been reported using ship-based observations, but detailed knowledge of the migration of pelagic birds was difficult to obtain until the development of geolocators gave long-term tracking capabilities. Non-breeding period movements of several oceanic species have now been determined in detail. The current study aimed to establish the wintering tracks of Kittiwakes from Lowestoft, an urban colony in the east of England, and also to determine the similarity of annual tracks in individual birds. Commencing in 2012, geolocators were fitted to adult Kittiwakes breeding on Claremont Pier, and up to 2018 data from 15 birds were obtained, including up to four years’ tracks from individual birds. It was found that Kittiwakes from Lowestoft had highly varied tracks, covering virtually the whole range of wintering areas of birds from other North Atlantic colonies. However, individual birds showed a high degree of track repetition from year to year.
Seabird populations are declining worldwide (Paleczny et al. 2015). Various aspects of seabird breeding period behaviour have been studied in a number of species, but this period is often less than half of the year (Cramp et al. 1984). Much less was known about the distribution and behaviour of pelagic birds in the non-breeding (winter) period, when birds can face different pressures to those associated with the breeding colony, including pressures from extreme weather, lack of food and developments such as offshore wind farms (Wernham et al. 2002). Non-breeding season ringing recoveries are limited, and often from dead birds whose corpses may have travelled for long distances before being found (Coulson 2011). Sightings from ships (Rankin & Duffey 1948; Coulson 2011) are also limited and biased by ocean routes. The advent of geolocator tracking devices around the turn of the century has led to a major increase in opportunities for more scientific analysis of seabird distribution and movements outside the breeding season (Harris et al. 2009; Coulson 2011; Guilford et al. 2012; Fort et al. 2012).
Black-legged Kittiwakes Rissa tridactyla (hereafter Kittiwakes) are the most numerous gulls in the world and there are many studies on various aspects of their behaviour in the breeding period (Coulson 2011). Outside the breeding period they are highly pelagic, and during 2008–09 an extensive study of birds from 19 colonies in the North Atlantic was carried out using geolocators (GLS) (Frederiksen et al. 2012). The colony locations ranged from Arctic Russia to Wales in the east and from Arctic Canada to Newfoundland in the west. The study gave a large amount of information on movement and distribution, focussing on December, and showed that birds from most colonies covered a large range throughout the area, with a general preference for the northwest Atlantic. However, some birds from Norwegian colonies stayed in the North Sea, and birds from Skomer Island (off the coast of southwest Wales) and Rathlin Island (off the Northern Ireland coast) stayed largely in the Irish Sea and eastern Atlantic around Ireland. Kittiwakes from western Atlantic colonies (Arctic Canada, west Greenland, and Newfoundland) remained almost completely west of longitude 35°W (Frederiksen et al. 2012). Further GLS-based studies on wintering Kittiwakes include the effect of breeding success on winter tracks (Bogdanova et al. 2011; Ponchon et al. 2015; Bogdanova et al. 2017), and tracks in the North Pacific (Orben et al. 2015).
In many pelagic species individuals tend to return to the same wintering areas each year using similar routes. These include Atlantic Puffin Fratercula arctica (Guilford et al. 2012; Fayet et al. 2016) and Northern Gannet Morus bassanus (Kubetzki et al. 2009). In contrast, Cory’s Shearwaters Calonectris diomedea breeding on Selvagem Grande Island (between Madeira and the Canary Islands) have extensive, varied wintering areas, with some individual birds repeating the previous winter track closely, and others not (Dias et al. 2010).
Following this information, Kessingland Ringing Group (an informal group formed in 2004 which subsequently became a registered BTO Ringing Group in 2013) decided to investigate whether Kittiwakes from Lowestoft town, adjoining the most easterly point in the UK at 1°46’E 52°29’N, would travel out to the favoured northwest Atlantic area when the apparently suitable North Sea was so close. Lowestoft requires a longer journey to reach the North Atlantic than any of the other southeastern UK colonies, unless an overland route is used. The GLS-based study was intended to be carried out over several years, and so a second investigation concerned the extent to which individual birds would replicate their tracks over a number of years. This characteristic had not been documented in Kittiwakes when the current study started, although it was demonstrated in Puffins from Skomer Island (Guilford et al. 2011). Track repetition was subsequently documented for Kittiwakes (R. tridactyla polycaris sub-species) from the Bering Sea Pribiloff Islands colonies, which spend the non-breeding period in the Aleutian area of the North Pacific (Orben et al. 2015).
The author would like to thank two reviewers for advice which has improved and expanded the paper, Morten Frederiksen and Tom Dickins for advice and encouragement, James Fox (Migrate Technology) for advice on the use of GLS tags, Jez and Laura Blackburn for help at the initial GLS fitting session, Rachel Hallett for advice on the presentation of this paper, and members of Kessingland Ringing Group for their work at sessions to fit and remove GLS tags, particularly Derek Beamish for his catching abilities. Financial support for the GLS was received from Colin Carter, the Seabird Group, Waveney Bird Club, Lowestoft RSPB Members Group, Lowestoft Lounge Lizards, Mr. John Garbutt, and others.
Colin Carter (1940–2017)
Colin started ringing as a teenager, and with some breaks due to his career, he remained a dedicated ringer. On retirement he started ringing at Kessingland near Lowestoft in 2004, and was soon joined by the author and progressively more ringers, usually as trainees. In 2012 he initiated the Kittiwake GLS project, and this was continued on the conversion in 2013 to a formal group (Kessingland Ringing Group), with Colin as Group Leader until he died in 2017. He led every ringing session where GLS tags were involved, and without him this project would not have happened.
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