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, 18 May 2012

A far from normal spring

It has been anything but a normal spring. March, with its early spring Mediterranean overshoots, at times felt like May. April, with its heavy rain, snow and hail, resembled November, and so far May has felt very unspring-like.

Swallows and House Martins sheltering from the Rain
in Mevagissey, Cornwall, by David Jackson. May 2012

What effect has this had on our migrant birds?

March 2012 became the third warmest March on record, with temperatures often exceeding those in southern Europe.  As a consequence, early March saw higher than average arrivals, for the time of the year, of Wheatears and Swallows. As the month progressed and the temperatures held, it felt more and more like southern Europe and the arrival of over thirty Hoopoes, a couple of Purple Herons, Baillon’s Crake, Woodchat Shrike and Scops Owl only served to reinforce this.

Just as it seemed like spring migration was about to step up a gear the weather turned. April will be remembered as one of the wettest on record, overturning drought warnings in some counties to flood warnings. It wasn’t only in the UK that this weather pattern dominated, southern Europe suffered too.  On 16 April, the mid-morning temperature at Aiguamolls de L’Emporda, northern Spain, was 5 degrees, forcing migrating Swallows to seek shelter in the hides of the nature reserve.

Swallows at Aiguamolls de L'Emporda by Rod Leslie

Further south, gale force winds whipped up huge sandstorms over the northern Sahara and out into the southern Mediterranean Sea, forcing migrants into the water and providing a bonanza for feeding Lesser Black-backed Gulls. The March rush slowed down as rapidly as it had begun, and many of our migrants began to look like they were going to be late back this year. Whitethroats didn’t start to arrive in earnest until late April/early May, two to three weeks later than the norm.

BirdTrack results show that it was a similar pattern for several other species that normally arrive in mid-April, notably Hobby, Cuckoo, Turtle Dove and warblers including Grasshopper, Reed, Sedge and Garden Warblers. BirdTrack reporting rates for all these species are striking, as are those of both Whitethroat and Lesser Whitethroat.

Hobby by Jill Pakenham

So, here we are, mid-May and the weather is decidedly cool and wet. The winds are in the main coming from the north, and for the most part are quite strong. Even though most of our summer migrants are now represented, there are parts of the country in which many are still to arrive. When conditions allow, there are still some impressive movements of birds at coastal watchpoints, so migration is far from over yet and will almost certainly still have some surprises up its sleeve.

This coming weekend the northerly winds are due to turn more southerly, then south-easterly and eventually easterly. If this is the case, migration watchers on the east coast could be in for a bonanza, and as we are moving into the latter half of May, anything could turn up. I know that I’ll be out in search of a Red-footed Falcon or two.

Friday, 11 May 2012

Migration slows a little.

With the mass arrival of many of our common migrants last week, Whitethroats, Garden Warblers, Swifts and Swallows poured in, it is hardly surprising that this week has been a little slower. That said, migration has been steady, with more Swifts, Swallows and House Martins arriving, along with Spotted Flycatchers, Turtle Doves and the first Nightjars.

Nightjar by Neil Calbrade

It has been the rarities that have grabbed the headlines, with both Calandra and Crested Larks turning up, both in Kent. At least three Pallid Harriers graced the east coast and, what continues to be one of the best springs for a long time for Black-winged Stilt continued with the appearance of four birds together in Kent. Red-rumped Swallows reached double figures, with at least fourteen birds being found, from the Isles of Scilly to North Yorkshire.

Will it be a good weekend for migrants?

It looks like it is going to be a largely dry but windy weekend. The wind will come from the north and north west on Saturday, dropping during the afternoon, and turning south westerly overnight and through to Sunday morning, only to increase in strength again. So, it looks like Sunday morning might be the best time to be out watching visible migration, or in search of grounded migrants.It is hard to say what might turn up. The light northerlies of Saturday afternoon and evening might coax something like a Great Reed Warbler this far north.

Friday, 4 May 2012

The floodgates open

As soon as the wind turned south-easterly and dropped they began to arrive in their hundreds and thousands. Many sites had their largest falls of the spring so far and some hinted at their largest falls ever, but what was sure was that the migrant floodgates opened at last.

As the week progressed the wind turned northerly but for the most part remained light, perfect conditions to observe visible migration. At Portland Bill, Dorset over 10,000 Swallows were estimated to have flown through on the 3 May, whilst in previous days there were at times too many to count.

On the Isles of Scilly, flocks of warblers, largely Blackcaps and Willow Warblers but also containing Garden Warblers and Common Whitethroats, were seemingly everywhere. This is reflected nicely in the BirdTrack reporting rate.

Common Whitethroat by Amy Lewis

With Swifts and Spotted Flycatchers also making it back, the first Nightjar won’t be too far behind them. Two of the BTO satellite tagged Cuckoo’s also took advantage of the weather and arrived back in the UK after spending the winter in the Congo Rainforest, for more information and to see their full migration routes.

Cuckoo by Steve Ashton

Southern overshoots have also been well represented. Five new Cattle Egrets arrived, along with the first Squacco Heron of the year, five Black Kites, three Short-toed Larks and at least seven Red-rumped Swallows. Whilst from the east a Citrine Wagtail and Red-breasted Flycatcher were found in Norfolk, and a Black-winged Pratincole arrived in Cheshire.

The wind is due to stay in the north-east and remain fairly light throughout the weekend, turning southerly on Monday, perfect conditions for further arrivals of common migrants and vagrants from the south and east. So if you haven’t heard a Cuckoo this weekend could be the time to get out and listen, and if you do hear one you can support the BTO Cuckoo project by texting a donation to CKOO12 £2/£5/£10 to 70070, and  if you’re out looking for vagrants, a Rock Thrush might just be on the cards.