Up to one million Fieldfares cross the North Sea each October. To some extent the autumn movements of flocks are resource-determined, leading to significant variability in the numbers reaching Britain & Ireland. From ringing recoveries, we see that some birds return annually to the same local orchards whilst others may wander in completely different directions in two consecutive autumns. The recovery map of BTO-ringed Fieldfares includes birds recovered as far east as Turkey. It is assumed that flocks of birds move south, as food resources become depleted, which may take a Russian Fieldfare to Warwickshire in one year and to Ukraine in another.
This BirdTrack graph shows the percentage of birdwatchers’ lists that contain the species. Blue represents this year and red is the average for the previous five years (right).
Fieldfares “are widely distributed in winter, with the exception of major urban areas and the highest ground in northern Scotland and in northwest Ireland” to quote from the text in the new book. Within these islands, as the winter abundance map alongside shows, “there is a preference for low-lying land in southeast and central England”. We hope that the Winter Thrushes Survey will help to explain how the species’ distribution over the course of the winter is linked to food availability.
“The winter distribution map shows a 4% range expansion since the 1981–84 Winter Atlas, with gains confined mainly to the Scottish Highlands, Hebridean islands and the west of Ireland. Although some of this increase is likely to be due to improved coverage in these marginal areas, the two severe winters of 2009/10 and 2010/11 may have forced greater numbers of Fennoscandian immigrants into western parts of Britain and Ireland”.
Using data from Timed Tetrad Visits, we can model the winter abundance of Fieldfare, with darker blue indicating higher densities (left).
Fieldfares feed in open farmland and hedgerows, only moving into gardens during harsh winter weather, when they are often associated with fallen fruit still lying under apple trees. In some areas, such as the southwest counties of the Midlands, four-figure flocks can be seen descending upon orchards, to feed on apples that were not picked in the autumn.
In a report by JNCC, the authors show Ordnance Survey data relating to orchards, which “are dispersed throughout the lowlands of Britain, although there are concentrations in some areas, particularly Kent, Cambridgeshire, Somerset and the Three Counties ( Herefordshire, Worcestershire and Gloucestershire). The bulk (78%) of the commercial fruit production occurs in these concentrations in England…”
It would be interesting to look at the Atlas maps, perhaps alongside the Winter Thrushes Survey data, to see how much association there is between orchards and the species’ distribution.
This OS map of orchards appears in a JNCC report entitled UK Biodiversity Action Plan: Priority Habitat Descriptions: Traditional Orchards (jncc.defra.gov.uk/Docs/UKBAP_BAPHabitats-56-TraditionalOrchards.doc) (right).
BirdTrack data reveal that, having peaked at the turn of the year, when they appear on an average of 25% of birdwatchers’ lists, Fieldfares gradually disappear over the course of the first four months, with the last birds returning across the North Sea at the end of April. This slow drop in occurrence rate may show that birds are disappearing from western lists, as flocks move towards the east, but we will learn more through the current Winter Thrushes Survey. In the cold spring of 2013, larger numbers of birds stayed with us until mid-April, followed by a rapid departure as the weather improved.
As will be seen in the Atlas, “Fieldfares are clearly very rare breeders with just a handful of 10-km squares showing evidence of breeding, mostly in Scotland and northern England. Breeding was confirmed in just four 10-km squares, in the Cairngorms, Shetland, Scottish Borders and Peak District. Breeding is not always confined to the north: a pair bred in Kent in 1991”.
Breeding distribution of Fieldfare during the breeding seasons 2008 to 2011 (left). Grey dots indicate spring records of winter migrants, most of which are in April.
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