STAGING ECOLOGY
Used on both spring and autumn migrations, Iceland provides a stepping-stone lying intermediate between the wintering and breeding range. Undoubtedly the western fjords and bays provide the most abundant food resources at this latitude - the last plentiful resources for the northward spring migration and the first on the southerly late summer migration. As such it is likely that the feeding provided in Iceland is crucial to ensure onward successful migration and, in the spring, may well contribute to reproductive investment by female geese.
Prior to 2002, Icelandic studies have focussed on distribution, a telemetry study {SEE SECTION SATELLITE TELEMETRY - LINK} and intermittent studies of marked individuals. Then and now, most studies in Iceland occur during the spring migration.
Following Gudmundsson and Gardarsson's paper in 1997, a long-term monitoring project at Alftanes in Iceland {MAP} began. Numbers utlising this site have gone up by X% in the last 10 years. In spring this site now holds approximately 3,000 birds. {Graph of increase?}
The initiation of a marking/resighting programme in 2001 in Ireland was matched in Iceland and large numbers of geese have been caught annually since, principally at the staging area in Alftanes in the south-west.
Not surprisingly the majority of the XXXX observations of ringed birds in Iceland have been at Alftanes but the increasing numbers of birds marked throughout the flyway and increased collaboration with UK/Ireland co-workers have located marked birds at other sites. We hope that in time we will understand the way sites are utilised by individuals within- and between seasons. {MAP of locations at which observations have been made}.
The intensive observations at Alftanes have shown that the typical peak of immigration in spring occurs in mid-May, with first arrivals in late March and all but a few Brent departing in late May {GRAPH, Reference}. Long-term monitoring of numbers
In spring 2007 work by Auhage examined a range of aspects of spring staging ecology including activity budgets and habitat use.
Sub-arctic staging areas such as western Iceland are undoubtedly important refuelling areas in spring and autumn. Of particular interest is the importance of food resources acquired in Iceland in spring for fuelling the onward 2000km migration to the breeding range where conditions are unpredictable as spring is only arriving. For females the question is whether they can rely on locally acquired resources to invest in egg production or do they have to bring additional 'capital' reserves to do this. Maybe only those individuals that acquire sufficient reserves in Iceland and have a relatively unobstructed migratory flight have sufficient reserves in late thaw spring conditions in the breeding range to successfully breed. Or maybe in moderate years (with early snow-melt and elevated temperatures) most females old enough to breed can do this irrespective of the reserves they accumulated in Iceland.
Understanding this is easier said than done but it is a key to gain a fuller understanding of the dynamics of the population. In turn identifying the importance (or not) of Icelandic staging grounds for breeding investment would further arguments for ensuring conservation of important sites there.
We have been using body profile indices as a measure of body condition. We consider this to be the best unobtrusive measure of body condition that we can get and we score individuals in head down feeding position on an ordinal score ranging from API (Abdominal Profile Index) 1 to 7 (BOX).
This enables us, without catching them, to assess the body condition of individuals through observation; the graph of APIs of individuals in spring is quite informative {GRAPH}
Information box showing profiles and pictures of birds.
Greenland