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 26 October 2012

Thrushes arrive in force

Over the last few days one of the biggest natural events of the autumn has been unfolding along the east coast with the arrival of hundreds of thousands of thrushes.

Redwing by Andy Mason

By far the biggest arrival occurred at Spurn, East Yorkshire where over 21,000 Redwing, 10,000 Blackbird, 9,000 Fieldfare, 800 Song Thrush, 57 Ring Ouzel and 10 Mistle Thrush were counted on the 22nd. Until then Fieldfares were conspicuous by their absence and the BirdTrack reporting rate shows just how late they are arriving this autumn, in comparison to the previous two years.

Along with thrushes were large numbers of other typical late autumn migrants, with Robin, Goldcrest and Brambling also arriving in force. There were numerous records of Black Redstart, usually a fairly scarce migrant and winter visitor, and a mouth-watering trio of eastern rarities appeared too! Britain’s first ever Pale-legged Leaf Warbler, which breeds no nearer than southeastern Russia, was found on Portland, Dorset. The Western Palearctic’s third Chestnut-eared Bunting, a species breeding from the Western Himalayas, China to southeast Siberia, arrived on Shetland, and Britain’s tenth Siberian Rubythroat, also on the Shetland Islands, added to an incredibly exciting period.

Waxwing by Andy Mason
Swallows and House Martins are still moving through south coast sites in double figures. At Hengistbury Head, Dorset, 79 Swallows and 41 House Martins moved through on the  yesterday morning of the 24th.
Starlings also began moving this week with over 5,000 being counted moving west on the North Norfolk coast on the 20th, and around 30 Waxwings have arrived in the north.

Little Auk by Andy Mason

With the winds turning northerly and forecast to be quite strong at times the focus could well be on birds moving just offshore. An arrival of Little Auks looks like a good bet, along with good numbers of wildfowl, and possibly more Waxwings. With frosts forecast for early next week Skylark and Woodpigeon could also move in impressive numbers. With the winds coming straight out of the Arctic this weekend, the rarity value could well be in the shape of a Snowy Owl.

Wednesday 17 October 2012

A mixed bag for Migrants

As a series of weather fronts arrive from the west over the next few days, the winds will swing from west to east and back to west several times during the course of the week. Southern counties are forecast to bear the brunt of the westerly airflow, whilst the north will receive the lion’s share of the easterly winds.

This mixed bag of weather could bring something for all of us. With most of the country experiencing winds with some east in them on Wednesday afternoon/Thursday morning, this could be the time to get out and observe migrants on the move. Swallows and House Martins continue to move apace; both of have produced some late broods (see Stuart Winter's article) this year so numbers on the move might remain a little higher for a bit longer than is usual for the time of year.

Fieldfare by Jill Pakenham

During the past week Redwings have arrived in force in the north but numbers in the south still remain quite low, this could change as we go into the weekend. Fieldfares are running late, as evidenced by the BirdTrack reporting rate. However, during the relatively calmer conditions between weather fronts this could change and we could see a large arrival of these impressive thrushes. A perfect time for another walk for the BTO Winter Thrushes Survey!

Finches and buntings should begin to move, with a change in focus from Goldfinch to Chaffinch. An increase in the number of redpolls should also be evident too. Lapland and Snow Buntings will be the buntings to look out for on the east and northeast coasts, whilst Reed Buntings ought to feature in good numbers in migration counts along the east and south coasts.

 Common Nighthawk by Bryan Thomas

With the whole of the country experiencing strong onshore winds at some time during the week a seawatch could pay dividends for those so inclined. Gannet will be the main feature but Arctic, Pomarine and Great Skuas, along with late Common, Arctic, and Sandwich Terns could move through. Red-throated Diver numbers will continue to build, and smaller numbers of Black-throated and Great Northern Divers can be expected as well. Regarding rarities, birds from both the west and east should be on the cards. Common Nighthawk from the west and Siberian Thrush from the east would fit the bill nicely.

Friday 12 October 2012

Migration stalls a little

After the rush of American birds in the west last weekend, things have quietened down somewhat.

Right now finches should be keeping ‘vis miggers’ (visible migration watchers) very busy but for the most part visible migration has been fairly disappointing for them. There has been the occasional busy period mixed in amongst almost birdless days at some migration watchpoints.

Goldfinch by John Harding

The finch counts at Spurn Bird Observatory illustrate this perfectly. On 8 October, around 2,000 finches were counted flying over, including 1,411 Goldfinches. The finch count for the very next day couldn’t have been more different with only five Bramblings and no goldfinches counted, and very little else on the move. With reports of a failure in the beech mast crop in Scandinavia, we could be in for a large arrival of Bramblings any day. The BirdTrack reporting rate shows the peak arrival time for this beautiful finch well.

At this time of the year a bit of east in the wind generally triggers common migrants to get moving, couple this with the odd shower or two and any birds moving overhead can be grounded. These were just the conditions that Portland Bird Observatory experienced on the same day that Spurn had its large finch movement. On 8 October around 200 Robins were grounded at the Bill, and were much more numerous around the centre of the island. The weather also grounded the first noticeable movement of thrushes, which included 50 Blackbirds, 40 Song Thrushes and 25 Redwings.

The easterly winds from the early part of this week will turn westerly as we go into the weekend, bringing heavy rain to the south west. However, on Sunday the winds will again turn easterly for a short time and maybe prompt a large movement of finches and the first big movement of thrushes, (this weekend could be a good one to take part in the Winter Thrushes Survey) and possibly Skylarks.

Gannets by Edmund Fellowes

If you are looking at the sea this weekend then the south west will be the place to be on Saturday but east coast seawatchers might get higher returns for their efforts on Sunday. Common Scoter traditionally begin to move in large numbers around mid-October and there is always a chance of the odd Velvet Scoter mixed in with them. Gannets should feature highly and Red-throated Diver numbers should increase and include the odd Black-throated and Great Northern Divers.

As for rarities? We are just coming in to the peak period for the rarity mecca that is the Isle of Scilly and with a low pressure system arriving from across the Atlantic tomorrow morning an American passerine has to be on the cards for the islands. Whilst I still fancy Black-billed Cuckoo for this autumn, the first American Redstart for the archipelago would set pulses racing.

Friday 5 October 2012

Get ready to welcome some winter visitors

As the low pressure to the south of us moves away to the east, high pressure will take its place over the weekend, bringing with it much lighter winds and a change in the direction of those winds, from westerly to south easterly, at least for the latter part of the weekend.

Redwing by John Harding

These lighter winds and the direction change could result in the largest arrivals of some of our winter visitors so far this autumn. Bramblings, Redwings, Fieldfares, Song Thrushes and Blackbirds should all feature. So, this weekend could be a good weekend to take part in the BTO Winter Thrushes Survey.
Pink-footed Goose numbers should also build this weekend and anyone with access to the east coast could see Red-throated Divers on the move. 

Jays are still on the move, at least 278 were reported over Cley, Norfolk, on 4 October, and birds continue to be seen in unusual numbers and in unusual places. The BirdTrack reporting rate for Jay routinely climbs at this time of year. However, the reporting rate for the first week of October was the highest in 8 years of BirdTrack records. The majority are likely to be native birds dispersing from breeding areas in search of food.

Blue Tit by Liz Cutting

Across the North Sea, Blue Tits have been on the move in unprecedented numbers. On 1 October, 87,400 were counted migrating from Nabben, Falsterbo, Sweden. To get a taste of this take a look at this short video. It seems that the Beech seed crop has failed in northern Europe, so this year could see a Brambling winter. Perhaps a sign of things to come, was a flock of 90 Brambling on Fair Isle, Shetland, last week.

Brambling by John Harding

With news of the Western Palearctic’s first ever Eastern Kingbird at Inishmore, Galway, and a Yellow-rumped Warbler on Dursey Island, Cork, who knows what other North American birds are waiting to be found. Whether looking for lost waifs and strays or counting visible migration, this weekend promises to be an interesting one.

Tuesday 2 October 2012

Black-billed Cuckoo - not quite!

The depression that tracked across the Atlantic and arrived on the west coast this weekend didn't bring the predicted Black-billed Cuckoo with it. It is twenty-two years since the last Black-billed Cuckoo graced our shores; that bird was found on St Mary's, Isles of Scilly on 10 October 1990.

There have been fourteen accepted records of the species in Britain and Ireland, with the dates ranging from August 29 to November 8. It is thought that the population is declining in North America but their populations vary considerably from year to year as they follow fluctuations in the abundance of their caterpillar prey. The fifteenth record is long overdue; will this be the year?

Black-billed Cuckoo (Ontario) by Luke Delve

The low pressure system did bring a few other North American birds with it, however. Three more Buff-bellied Pipits were found on Shetland, four American Golden Plovers arrived, one on Orkney, one on Shetland and two in Ireland, and a new Buff-breasted Sandpiper was seen on the Isles of Scilly.

Common migrants were also in evidence, with the general exodus of Swallows and martins still underway. Finches began to move, with Bramblings, redpolls, Siskins, Linnets, Goldfinches and Chaffinches well represented at migration watchpoints.

Rather curiously, Jays seem to be on the move and there is some debate as to whether these might involve continental birds or whether they are our own birds that are moving in search of food. The latter might explain the steady westerly movement out of Thetford Forest, on the Norfolk/Suffolk border on Saturday morning. The acorn crop here is patchy at best this year. However, there is also evidence of birds arriving from the continent. During a large movement of Jays on 29 September at Bockhill, Kent, a group of thirty-four were observed arriving in off the sea. The BirdTrack weekly reporting rate for Jay shows this upsurge in observations well.

Jay by Tommy Holden

The winds will be largely from the west and southwest this week but they will be fairly light midweek, so Wednesday morning could see the first big finch movements of the autumn.