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 16 November 2018

A Swift arrival

The migration highlight in the last two weeks was an unexpected arrival of Swifts from 3 November onwards, with three species noted around the country. While there were a handful of Common Swifts reported, the majority of sightings involved the much rarer Pallid Swift, with over 30 and perhaps as many as 50 individuals observed.

BirdTrack reporting rate for Pallid Swift

Pallid Swift is seen annually in Britain in small numbers, influxes involving more than 10 birds had previously occurred only in 1999 (11 records), 2001 (12) and 2004 (15). The majority of the sightings came from the east coast, with only a handful from south coast counties and inland sites. Besides Britain, one was seen briefly in Ireland and up to 20 Pallid Swifts were also noted in the Netherlands, where there had only been 12 records previously.

Pallid Swift by Martin Cade
A potential reason for the influx may be that unusually for European swifts, Pallid Swift is double brooded, with the last brood fledging in October. Additionally, the sustained southerly winds throughout early November may have pushed birds northwards. The presence of a Little Swift at Hartlepool, Durham joining a Pallid Swift already present is intriguing as the nearest breeding grounds are along the southern Mediterranean coast. Did the Pallid Swifts in this influx come from North Africa rather than Iberia or the eastern Mediterranean?

Little Swift by Damian Money
The week ahead looks potentially quite interesting, with high pressure building over western Russia and Scandinavia over the weekend. This could potentially bring a spell of colder weather from the middle of next week onwards, with the easterly winds likely to bring more winter thrushes and wildfowl amongst others to our shores. It is getting a bit late in the season for most rarities by this stage, but given the origin of the winds, a Desert Wheatear, or perhaps even a Desert Warbler, seem like potential arrivals.

Stephen McAvoy

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