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 30 March 2012

Amazing week for migration

This week has been amazing for migrants. At times it has felt more like early May than late March, both in terms of the weather and the birds.

Around thirty Hoopoes arrived, mainly in the south and west, along with the first Purple Heron of the year.

Common migrants have also taken advantage of the continuing good weather conditions and the first Cuckoos, Redstarts and Pied Flycatchers arrived.

Birds arriving ahead of schedule included a Reed Warbler in Norfolk and a Common Swift in Dorset. Grasshopper Warblers were found at several sites, along with a few Sedge Warblers and the first Garden Warbler.

As March turns into April migration should step up a gear, and with cloudy skies and light winds forecast fort this weekend visible migration watchers could be in for a busy time. The first large arrival of Willow Warblers is on the cards.

Monday 26 March 2012

A taste of the Mediterranean

The weekend's predicted Great Spotted Cuckoo didn't turn up but there was a multiple arrival of Mediterranean overshoots. At least half-a-dozen Hoopoes were found, predictably all in the south-west, where there was also a very early Wryneck and Scops Owl. Three Alpine Swifts were seen; one making it as far north as the Butt of Lewis, Outer Hebrides. A Woodchat Shrike was found in Waterford, Ireland but the pick of the bunch, also in Ireland, was a Baillon's Crake, found on Great Saltee, Wexford. The nearest breeding area for this species is in northern central France.

Wryneck by Jill Pakenham

Common migrants didn't disappoint either, Chiffchaffs arrived en-masse and made it as far north as Shetland. Swallows and Sand Martins became more widespread, and there was a further arrival of House Martins. A handful of Tree Pipits were seen, two weeks ahead of their average arrival date of April 6, whilst the Turtle Dove seen in West Sussex is almost a month ahead of its average arrival date of April 20.The Sedge Warbler, Seen in Oxon on Sunday, is the first of the spring, and twenty-one days ahead of its average arrival date.

Sedge Warbler by Dawn Balmer

There were a couple of reports of Cuckoo over the weekend but none were pinned down or reported subsequently. The BTO satellite tagged birds are all still south of the Sahara desert, three are in Ivory Coast and one in Ghana. Presumably these birds are using this part of West Africa to prepare for the long journey north back to the UK. Having spent most of the winter in Congo, these birds could make their move across the Sahara in the next week or so. You can follow their journey .

The weather for the coming week is set to change very little, so we should see the arrival of more common migrants and more overshoots from the Med, all taking advantage of the light winds over southern Europe and the UK.

One of our partners at BirdGuides will be spending the next three months studying migration at Falsterbo, Sweden, and keeping us up to date with movements there.

Judging by the snowdrops and crocus, spring here at Falsterbo (southern Sweden) is a good few weeks behind what it was when I left northwest England. Migration has been noticeable here over the past four days — but the bulk of the species caught perhaps weren't what we in the British Isles would associate with being typical spring migrants. Of the 176 birds ringed on Friday, 117 were Robins.

Black Redstart by Stephen Menzie

Chiffchaffs are passing through — as are Wrens, Dunnocks, finches and thrushes. The last few days have seen an increase in numbers of White Wagtail, while on Sunday two Black Redstarts were seen on the peninsular including a stunning adult male ringed at the lighthouse garden. A Sparrowhawk carrying a Danish ring hinted that there might be some movement of raptors from 'across the water', while up on the heath buzzards were moving — a dozen of so Common and two Rough-legged. An Osprey was seen over the weekend and a number of Common Cranes have passed through but we're still waiting on our first Blackcaps, Wheatears, Swallows and Sand Martins.

I'll be in Falsterbo for the next three months and will be providing regular updates of how the spring is progressing over here. I'll also be updating my own blog each day with ringing news and sightings.

Friday 23 March 2012

Migration picking up speed

With a settled high pressure weather system over most of southern Europe, conditions have been looking ideal for migration to take place. It came as no surprise then, when migrants began to turn up. Chiffchaffs have been the most noticeable this week, with singing birds heard overlarge parts of the country. The BirdTrack map shows this nicely.

Meadow Pipit by Nigel Clark/BTO

Although the first large movement of Wheatears and Swallows is still to happen, a few individuals of both species have made it as far north as Highland, Scotland. A handful of Willow Warblers arrived last week too, as expected, mainly in the south. Meadow Pipits finally started to move; 1650 were counted during a visible migration watch at Hengistbury Head, Dorset on the 22nd, along with a smaller number of ‘alba’ Wagtails (Pied / White). The first Stone Curlews arrived back on their breeding grounds in the Norfolk and Suffolk Brecks, and the first House Martins were seen on the Isles of Scilly and in Northumberland.

Sand Martins arrived in sufficient numbers to form small flocks; 32 together in Lancashire was amongst the largest. At least eight Ospreys were logged, with sightings from Surrey to North Yorkshire, and an Alpine Swift spent the weekend on the Lizard, Cornwall, joining the three or four Night Herons that have arrived in the south-west.
With the weather set to continue in a similar vein, early migrants that have made it into southern Europe should begin to pour north. The high pressure system that is now over the UK stretches all the way from northern England to the northern shores of the Mediterranean, with the whole area experiencing light winds.

Serin by Su Delve

With a singing male Serin being found on the Isles of Scilly, and a Hoopoe in Cornwall in the last few days, other southern European overshooting migrants could be on the cards. A Great Spotted Cuckoo – a classic early-spring overshoot – would be a nice find!

Thursday 15 March 2012

Migrants hit by Saharan storm

In yesterday's blog, I was surprised by how few early migrants have arrived and thought that they might be facing problems much further south. We have since received an email from Andy Williams, who is working on a survey vessel just off the coast of Libya, that might help explain the hold-up.

I'm currently offshore Libya- about 15-30 nm north of Tripoli undertaking some seabird/cetacean survey work for an Italian client. I have seen a smattering of migrants- white wagtails, stonechat, black redstart, chiffchaff, blackcap, hoopoe, lesser kestrel etc over the past couple of weeks but all in very small numbers. (maybe a tad early or wrong location for big numbers?) Anyway the central and western med. has just had a significant storm over the last 4 days or so with F10 (storm force) winds and huge quantities of airborne sand and dust from the sahara.

This morning I observed yellow-legged gulls and lesser-black backs feeding on the sea surface- I initially thought they were taking squid or small fish then realised with some horror that the sea was littered with the corpses of passerines- all pretty unidentifiable as they have been waterlogged and thrashed about by the sea. I counted at least 11 corpses that were not actually eaten by the gulls. I could only observe the very small bodies out to about 20 metres from my vessel but the gulls were busy scavenging over a much wider area- impossible for me to quantify the number of dead migrants but certainly scores if not hundreds! I have never actually witnessed this before or heard of
similar accounts so though it would be pertinent to let you and the BTO know as there is currently so much interest in the 'out of Africa' program. (I have previously witnessed 'weak flyer' species such as quail crash into the sea before but have not seen anything like this previously).

To see some photographs, please see Andy's blog.

Wednesday 14 March 2012

Migration slowly getting under-way.

Everything was seemingly in place for a good weekend of visible migration, the winds were light and from the south, pretty much all the way from North Africa to the Midlands, and the temperature was generally higher than the norm for this time of the year; a sure-fire recipe for summer migrants to arrive and winter visitors to leave. So, why didn’t it really happen?

My guess is that the number of migrants staging in southern Europe is still pretty low and, as a result, when the right weather conditions presented themselves only a small number of birds responded. It could be that some of our migrants are held-up much further south, in Africa. As far as the winter visitors go, the BirdTrack reporting rate is still at 50% of the mid-winter high for Redwing and Fieldfare, so some have left. The remainder have vacated gardens after the brief cold spell and are now in the wider countryside again. It is a similar picture with wildfowl; some have already left and the rest will do so over the next month or so, in a less hurried fashion.

Garganey by Dawn Balmer

So what did arrive over the weekend? Twenty-seven Garganey were counted from Dorset to Norfolk. Being one of our earlier summer visitors, these were bang on cue. The same couldn’t be said of the Lesser Whitethroat seen in Essex though; the average arrival date for this species is 23 April. Of course, this bird could well have spent the winter much closer to Essex than sub-Saharan Africa. This might also be the case with the Whitethroat, also heard singing in Essex, as the average arrival date for this species is 15 April.

A very small number of Sand Martins and Wheatears trickled through, reaching as far north as Lancashire, and the first Willow Warbler was heard in Devon, twenty days ahead of its average arrival date of 31 March.

The first overshooting southern European migrant, in the shape of a Short-toed Treecreeper, put in a brief appearance in Kent over the weekend but disappeared almost as soon as it was found, whilst there are (as yet unconfirmed) reports of a female Rock Thrush in Cornwall.

Although the high pressure that has dominated during the last week will move off to the east over the next few days, the conditions are still favourable for migrants to arrive from the south.This weekend could be a good one to be out and about, with Saturday looking a slightly better bet than Sunday.

Stop press! The first Little Ringed Plovers have been seen in Dorset and Lancashire.

Thursday 8 March 2012

Early migrants trickle in

The run of early migrants has been hindered by the wet and windy weather of the last few days, with birds probably being held-up in central France. With high pressure now building over southern Europe and extending from Spain to southern UK, the next few days should see migration getting underway again, and indeed today has seen the arrival of a small number of Sand Martins, Swallows, Wheatears and a Ring Ouzel, the latter in Somerset, where another Osprey was also seen. With lighter winds forecast for the weekend it is looking good for more of these to turn up.

Chiffchaff by Amy Lewis

Spurn Bird Observatory caught their first Chiffchaff of the year on 4th March, though it is possible this was a departing bird that had spent the winter in Britain, rather than a returning bird from further south. Either way, the BirdTrack reporting rate shows that start of the main Chiffchaff arrival is imminent.

Shelduck by Jill Pakenham

At this time of the year it is not just about returning summer visitors, many of our winter visitors are departing right now and it is a good time to look out for flocks of Redwings and Fieldfares. If you are near the coast, skeins of Brent Geese and flocks of Shelduck, along with a smaller number of divers, mainly Red-throated, will also be on the move.

Monday 5 March 2012

A rude awakening

The light winds and generally mild conditions on Saturday saw Sand Martin numbers get into double figures, with birds being recorded as far north as Cumbria, Manchester and West Yorkshire, another Swallow was also seen in Cork, but what a difference a day can make. Temperatures plummeted on Sunday and counties from Norfolk to Scotland experienced some light snowfall.

Sand Martins and Swallows feed on airborne insects, which in the falling temperatures become harder to find, and whilst these early arrivals can survive two or three days of cold, inclement weather, by day four they are in serious trouble. Bad weather at this time of the year is normally associated with strong winds, which will prevent these pioneer migrants from just turning around and heading back south in search of better conditions. Unfortunately, during prolonged spells of poor weather many of these early birds will perish.

According to BTO BirdFacts, the average arrival date in the UK for the Sand Martin is 25 March, by which time the weather might generally be more settled and favourable.

So, these early birds are taking a huge gamble, if the weather is kind to them then the gamble will pay off and they will be back at their breeding sites securing the nest hole ahead of those birds arriving later, however, when the weather is bad they pay a high price indeed.

Sand Martin by Andy Mason

The strong winds forecast for the next few days will almost certainly put migration on hold, however, with lighter winds mid-week we might see the first Wheatears arrive.

Thursday 1 March 2012

Stop press!

The first Swallow of the spring was seen today in East Sussex, almost exactly one month ahead of the average arrival date of 29 March, as recorded in BTO's BirdfFacts.