Greenland White-fronted Geese Anser Albifrons Research Articles

Using accelerometry to compare costs of extended migration in an arctic herbivore.

Understanding how individuals manage costs during the migration period is challenging because individuals are difficult to follow between sites; the advent of hybrid Global Positioning System–acceleration (ACC) tracking devices enables researchers to link spatial and temporal attributes of avian migration with behavior for the first time ever. We fitted these devices on male Greenland white-fronted geese Anser albifrons flavirostris wintering at 2 sites (Loch Ken, Scotland and Wexford, Ireland) to understand whether birds migrating further during spring fed more on wintering and staging areas in advance of migration episodes. Although Irish birds flew significantly further (ca. 300 km) than Scottish birds during spring, their cumulative hours of migratory flight, flight speed during migration, and overall dynamic body ACC (i.e., a proxy for energy expenditure) were not significantly different. Further, Irish birds did not feed significantly more or expend significantly more energy in advance of migration episodes. These results suggest broad individual plasticity in this species, although Scottish birds arriving on breeding areas in Greenland with greater energy stores (because they migrated less) may be better prepared for food scarcity, which might increase their reproductive success.

Reconciling competing values placed upon goose populations: The evolution of and experiences from the Islay Sustainable Goose Management Strategy

The Scottish island of Islay hosts 45 000 barnacle geese Branta leucopsis (56% of the Greenland barnacle goose population, plus those passing through on migration), 5000 Greenland white-fronted geese Anser albifrons flavirostris (up to 30% of the world population) and 2500 greylag geese Anser anser, most of which feed on 9000 ha of grassland. The financial impacts of estimated agricultural damage have risen greatly over the past 20 years due to increasing goose numbers and higher farming costs. Mechanisms implemented to resolve conflict over time are reviewed for their effectiveness. Emphasis is placed on coordinating the implementation of strategic national conflict resolution at a local scale where the relative pressure from internationally important concentrations of geese on agriculture is acute. Despite the “local” nature of this problem, the benefit from the experience of decades of attempted conflict resolution and the effectiveness of existing programmes can contribute much to the regional and flyway dimensions of this international issue.

No evidence for sex bias in winter inter-site movements in an Arctic-nesting goose population

Understanding movement of individuals between sites is necessary to quantify emigration and immigration, yet previous analyses exploring sex biases in site fidelity among birds have not evaluated remigration (the return of marked birds that moved to alternative areas from the site at which they were marked). Using novel Bayesian multistate models, we tested whether between-winter emigration, remigration and survival rates were sex-biased among 851 Greenland White-fronted Geese Anser albifrons flavirostris marked at Wexford, Ireland. We found no evidence for sex biases in emigration, remigration or survival. Thus, sex biases in winter site fidelity do not occur in any form in this population; these techniques for modelling sex-biased movement will be useful for a better understanding of site fidelity and connectivity in other marked animal populations.

Spring ice formation on goose neck collars: effects on body condition and survival in Greenland white-fronted geese Anser albifrons flavirostris

During sub-zero temperatures and strong winds on 10–11 April 2013, we witnessed ice accumulation on plastic collars of staging Greenland white-fronted geese Anser albifrons flavirostris in Iceland. Ice affected 19 of 77 collared individuals seen, all of which had lost ice by 12 April, despite continuing freezing temperatures. Temperatures exceeded freezing after 14 April; daily observations found no recurrence of ice formation before geese left for Greenland in early May. Abdominal profile scores (a field assessment of accumulated body fat) did not differ significantly between geese with and without ice before departure from Iceland. There was no significant difference in return rates between geese with iced (79 %) or un-iced collars (83 %) reported the following autumn. These first reports of collar icing in over 30 years of the project give cause for concern and vigilance, but we recommend continued use of collars given exceptional weather conditions and lack of effects.

Earlier spring staging in Iceland amongst Greenland White-fronted Geese Anser albifrons flavirostris achieved without cost to refuelling rates

Greenland White-fronted Geese wintering in Ireland and Britain stage for 3 weeks in Iceland in spring before migrating onwards to breeding areas in west Greenland. The geese now depart their wintering quarters 12–15 days earlier than in 1973 because they attain necessary fat stores earlier than in previous years. Icelandic temperatures at critical midway staging areas have shown no significant change since 1973, creating a potential mismatch in food availability along the migratory route. Greenland White-fronted Geese have shifted from consuming below-ground plant storage organs in Iceland in spring to grazing managed hayfields created since the 1950s where fresh grass shoot growth occurs despite sub-zero temperatures, when traditional natural foods are physically inaccessible to staging geese due to frozen substrates. Rates of fat accumulation (measured by field scores of abdominal profiles) and mass change (measured in captured geese) were the same in the springs of 1997, 1998 and 1999 as in that of 2007 when the migration episode was 10 days earlier. Hence, earlier arrival in Iceland in 2007 did not occur at cost to refuelling rates there. The shift to acquiring energy from artificial grasslands has enabled Greenland White-fronted Geese to arrive in Iceland earlier, but has apparently not impaired their ability to accumulate fat reserves required for onwards migration, which occurs at the same rate, only earlier in the spring.

Warming winter effects, fat store accumulation and timing of spring departure of Greenland White-fronted Geese Anser albifrons flavirostris from their winter quarters

Migratory geese accumulate energy and nutrient stores in winter to fly to refuelling spring staging areas before onward migration to breeding areas. Mean ground temperatures at two important Greenland White-fronted Geese wintering sites rose in winter and spring by 1.0–1.3°C during 1973–2007. Greenland White-fronted Geese departed the Wexford winter quarters on 3rd April 2007 for Icelandic spring staging areas, the earliest on record, representing a mean advancement of 15 days since 1973, mirrored amongst mean dates of departure amongst Scottish wintering birds that have advanced by 12 days during 1973–2007. Icelandic temperatures at critical midway staging areas en route to Greenland showed no significant change since 1973, suggesting that it is warming on the winter quarters that enable geese to depart earlier, rather than elevated temperatures at ultimate spring staging areas. However, Wexford departure date did not correlate with spring temperature. Data presented here show that Greenland White-fronted Geese have accumulated threshold body stores progressively earlier in spring migration, especially during 1995–2007. Although this did not correlate with ambient temperature, the mean degree of accumulated fat stored by 1st April in each year was a statistically significant predictor of departure date for the wintering population at Wexford. These data support the hypothesis that it is intrinsic factors (i.e. improvements in internal body state resulting from better feeding conditions) that has permitted progressively earlier departure of these geese from Wexford on spring migration, rather than amelioration of spring conditions in Iceland or solely the result of warming of the winter quarters.

Staging site fidelity of Greenland White-fronted Geese Anser albifrons flavirostris in Iceland

Capsule Based upon resighting histories of marked individuals, a high level of site loyalty was found for Greenland White-fronted Geese staging in Icelandic stopover areas in spring and autumn. Aims To determine levels of within- and between-season staging site fidelity, to assess whether offspring adopt the staging areas of their parents and to determine relationships between Icelandic staging areas and winter provenance of individuals. Methods Sequential resighting histories and recoveries (2658 observations) of 415 different individually marked geese were analysed from the period 1986–99. Results In spring, > 90% of goslings associated with parents and siblings and all goslings were subsequently seen <4 km from where they were first sighted with parents in spring. Ninety-six percent of all multiple within-spring resightings of 192 marked individuals were within 4 km of each other; three geese moved 88 km from the southern to the western staging areas. Four percent of the 45 marked geese seen in two consecutive springs and none of the 27 birds seen in consecutive autumns moved more than 4 km between years. By contrast, significantly more (12%) moved greater than 4 km in subsequent seasons between spring/autumn (n = 56) and autumn/spring (n = 49). All these individuals shifted to Hvanneyri Agricultural College in autumn, the only declared hunting-free area for Greenland White-fronted Geese. Based upon resighting histories and recoveries of shot birds, Scottish wintering birds were more likely to use southern staging areas, and Wexford (Ireland) wintering birds were generally more likely to be seen staging in the western lowlands in Iceland. Conclusions Given the apparent cultural reinforcement of patterns of use of staging areas in Iceland, the high levels of site loyalty and the relatively limited exchange between southern and western staging areas, we argue for strategic refuge designation throughout both staging areas to protect the population.

Wildfowl of Islay

SynopsisThe island of Islay posssesses by far the largest population of wintering wildflowl in the Inner Hebrides; there are 18,000-20,000 barnacle geese Branta leucopsis and 4,000 Greenland white-fronted geese Anser albifrons jiavirostris. There is also a small flock of greylag geese A. anser. Most of the commoner dabbling and diving ducks spend the winter in small numbers, with a flock of 1,000 scaup Aythya marila the most important. A few hundred pairs of eider Somateria mollissima breed, and up to 3,000 wintering or moulting birds have occurred offshore. Other breeding duck are few in number, including up to five pairs of common scoter Melanitta nigra. Whooper swans Cygnus cygnus spent the winter in the past but are now common on passage only. Barnacle geese have trebled in numbers in the last twenty years, leading to complaints of agricultural damage, and a subsequent increase in shooting and disturbance followed by a recent decline in numbers. Annual data on populations, productivity and losses are presented. Greenland white-fronted geese have varied less in numbers, but shooting has increased and the situation is reviewed. All other wildfowl occurring on the island are dealt with briefly.