Siskin, Edmund Fellowes.

Migration blog (18th – 24th September)

Scott Mayson

BirdTrack Organiser

Scott's role includes the day-to-day running of BirdTrack: updating the application, assisting county recorders by checking records and corresponding with observers. Scott is also tasked with increasing participation in BirdTrack through a wide range of publicity media so if you are a birdwatcher reading this and you haven’t done so already, register and get started today.

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The next four weeks see the peak in autumn migration with greater diversity and numbers of birds on the move than any other time of year. As with all migration, the intensity is very dependent on the weather, wind direction, cloud cover, rain and fog. They all play their part in the timings of birds migrating and deciding which species turn up where and when. 

Although the past week has not been conducive for producing large arrivals of many migrant species, that doesn’t mean that migration came to a complete stop. The light winds meant there were movements of Meadow Pipit, Siskin, and hirundines (mainly Swallows and House Martins). As would be expected at this time of year, the numbers of warblers fell away as the majority of breeding adults and this year's young have already started their southward migration. Seabirds were generally reported at levels below what would be expected at this time of year. However, this is more likely a result of less than ideal sea-watching conditions than a reflection of breeding success. One species that bucked this trend was Sabine’s Gull. This elegant gull breeds in the high Arctic and is a scarce passage migrant in Britain and Ireland, but several birds were seen during the week across Britain and Ireland, with some individuals spending a few days at particular locations. The predominately westerly airflow also resulted in a slowing of wader arrivals with reporting rates for species such as Little Stint, Dunlin, Turnstone, Knot, and Bar-tailed Godwit all below where they would be expected at this time of year. However, several American waders arrived on the back of the westerly winds with some 32 Buff-breasted Sandpipers being the highlight and a supporting cast of several Pectoral, Semipalmated, and Baird’s Sandpipers. As we reached the middle of the week the wind direction swung to the east and with this swing came the first arrival of the more traditional early autumn fare: the first scattering of Yellow-browed Warblers, a true sign that autumn has arrived. Other species to arrive included more Lapland Buntings, which have already been arriving in numbers and at a variety of locations across Britain and Ireland. Sea-watching picked up with the onshore winds with Long-tailed Skuas, and both Sooty and Balearic Shearwaters being seen from a number of east coast locations. 

Rarity-wise the stand-out birds from the past week definitely had an American bias, with the highlight being the first Yellow-bellied Flycatcher for the Western Palearctic and Britain found on the island of Tiree, Argyll. Other rarities included a Sora (an American rail) on Lundy, the autumn's first Lanceolated Warbler in Orkney, and a Franklin's Gull in West Yorkshire.

During the summer months, the Skylark is to be seen, or more often heard, high in the sky singing its much-lauded song and will be a familiar bird to many. Its migratory habits, on the other hand, are less well-known. 

Species focus - Skylark

During the summer months, the Skylark is to be seen, or more often heard, high in the sky singing its much-lauded song and will be a familiar bird to many. Its migratory habits, on the other hand, are less well-known.

Within Britain and Ireland, most of the upland and northern Scottish breeding areas are vacated during the winter months. Autumn migration begins in Shetland and the Hebrides in late August and movements continue along the east coast into November. Movements out of Wales are also observed around mid-September when large numbers can be seen heading out into the Irish Sea and making for Ireland.

It is thought that most of the British breeding population winters in southern Britain. There is some evidence, albeit scant, that some may go as far south as Spain and Portugal. The large numbers seen moving along the east coast of Britain during October and into November are likely to hold lots of birds from the continent but it is unclear how many of these are just passing through on their way further south and how many stay to overwinter here.

Large numbers of Skylarks can also be seen on the move during the winter months in response to cold weather. Generally, these are birds moving south and west, escaping colder conditions further north. At this time there can also be large arrivals from across the North Sea. For a bird that spends all of its time feeding on the ground, prolonged periods of hard frost and snow cover can prove fatal. The British breeding population is estimated at 1,350,000 pairs but it has undergone a long-term decline and is Red-Listed as a Bird of Conservation Concern.

The weather for the coming week sees a real mixed bag of conditions and, as a result, could see a real mix of species arriving and departing Britain and Ireland.  

Looking ahead

The weather for the coming week sees a real mixed bag of conditions and, as a result, could see a real mix of species arriving and departing Britain and Ireland. This time of year sees the peak reporting rate for Great White Egret. This once very rare heron is now a regular breeding species in Britain and the peak in reporting comes as birds disperse from the breeding sites both from within Britain and from across Europe. Gannets also peak at this time of year, again as a result of birds leaving their remote breeding grounds and being reported further south; young birds even have a habit of turning up on inland waters after strong winds. Stronger westerly winds towards the end of next week could see the odd bird being found on a reservoir or other water body far from the coast, so keep an eye on any large bodies of water near you.

The weekend looks set to be dominated by the continued easterly wind direction, but a lack of rain will probably result in a smaller arrival than would be seen if rain was thrown into the mix. That isn’t to say that birds won't arrive. Whilst the main passage of warblers has slowed, Chiffchaffs are still on the move and can turn up anywhere, often associated with tit flocks. The migration of finches will gather pace and the numbers of Chaffinch, Siskin and Lesser Redpoll will increase over the coming weeks, with the arrival of the first Brambling of the winter likely to happen very soon. Other species to take advantage of the easterly wind include Skylark, Woodlark, Meadow Pipit and the first Scandinavian race (Anthus petrosus littoralis) Rock Pipits, which will be arriving for the coming winter or passing through to winter further south in Europe. With lighter winds and clearer conditions, Bearded Tits can be seen away from their favoured reedbeds as family groups disperse for the winter. They can be a surprise addition to a birdwatcher's local patch; listen for their distinctive ‘pinging’ call as they fly overhead.

Late September sees the peak arrival time for Lapland Bunting. 

On Sunday there is a small band of rain moving northwards from the south coast. The timing of this could see localised arrivals of species such as Goldcrest, FirecrestChiffchaff, Redstart and Pied Flycatcher as well as the first few Redwing, Brambling, Snow Bunting, Jack Snipe and Short-eared Owl of the autumn. The odd scarce species such as Yellow-browed Warbler, Little Bunting, Red-breasted Flycatcher, Red-throated Pipit and Short-toed Lark are also likely to occur. Rain arriving in the early hours of the morning is best for producing good ‘falls’ of migrant birds, so keep an eye on the weather forecasts to see when rain will be arriving. In fact, heading out after a spell of rain and easterly winds can often be productive at this time of year, no matter what time of day.

It has been a very productive year for Red-flanked Bluetail in Finland, with some 730 territorial males being recorded and, with a north-eastly wind forecast over the weekend, this once truly mega rarity could be found at locations such as Spurn, Gibraltar Point or the north Norfolk coast.

Early to mid-week, the winds swing around to a south-easterly direction before a weather front from the west arrives, bringing with it a band of rain and a switch to a south-westerly wind direction. The initial south-easterly wind could produce the odd Mediterranean vagrant such as Whiskered Tern, Sardinian Warbler, Woodchat Shrike or Hoopoe. The change to south-westerlies will most likely see a slowing of migration especially with the associated rain band. However, this front could bring more American vagrants to our shores with species like Red-eyed Vireo most likely. Any strong westerly winds at this time of year are perfect for Leach’s Petrel; west-facing coastlines are the most productive and sometimes birds can be driven very close inshore and even be seen flying along beaches.

Don't forget to add your sightings to BirdTrack either via the website or the mobile app. To find out more head to!

Scott Mayson, 17 September 2020

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