BTO migration blog

Spring and autumn are exciting times for anyone who watches birds. Here on this blog we will make predictions about when to expect migrant arrivals and departures, so that you know when and where to see these well-travelled birds.

Friday, 19 September 2014

House Martins head off.

With easterlies still dominating it is hardly surprising that birds from the east have dominated too. Two species have occurred in exceptional numbers during the week, with around ninety Red-breasted Flycatchers reported and a similar number of Yellow-browed Warblers, with at least nine on Fair Isle, Shetland on 16 September.

Yellow-browed Warbler by Joe Graham

Common migrants were also drifted across the North Sea and there have been good numbers of grounded Pied Flycatchers, Redstarts and Whinchats, and Wheatear numbers have begun to increase. Swallows and House Martins have taken advantage of the light easterly winds and have poured out of the country. During the week, visible migration watchers at Hengistbury Head, Dorset, recorded over 26,000 Swallows and over 38,000 House Martins moving through the site.
The latter half of the week saw a few Redwings and Fieldfares arrive but these were outnumbered by Song Thrushes, although the number of thrushes on the move was small in comparison to the hirundines and Meadow Pipits.

Finches have also started to move, with small flocks of Siskins moving along the east and south coast although we will have to wait until later in the month before they, and other finches begin to move in any number. Compare the two BirdTrack graphs below for Siskin and Chaffinch and note how Chaffinch observations begin to rise later than Siskin.

BirdTrack reporting rate for Siskin

BirdTrack reporting rate for Chaffinch

The winds are forecast to turn northerly through the latter part of the weekend and then westerly and south-westerly during the early part of next week. However, irrespective of the direction they are forecast to be relatively light. Birds will take advantage of this and continue to move but we should see a shift in the species composition. Hirundine numbers are likely to be less impressive but Wheatear  and Robin ought to increase. We could also see Redwing becoming more widespread and who knows, they might bring something else with them.

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