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 20 May 2016

What an amazing week

Calandra Lark by John Harding

If rare birds are what makes you tick, the last week or so has to be one of the best spring periods on record. Last week’s Caspian Stonechat, Calandra Lark and Dalmatian Pelican (if accepted as a wild bird) would take some beating and it would take a very special trio of birds indeed. However, Britain’s second ever Green Warbler, found on Shetland, Britain’s first ever spring Blyth’s Pipit and the first ever Lammergeier (if accepted as a wild bird) seems to have done the trick.
But what of our common migrants?

The week has seen a rush of hirundine passage, particularly through a few south coast watchpoints. During the morning of 19 May sample counts at Portland, Dorset suggested that Swallows were passing at a rate of 550 per hour. It is interesting to note though that the BirdTrack reporting rate for House Martin is behind the historic reporting rate, so we might have a large arrival of House Martins still to come.

House Martin BirdTrack reporting rate 

Spotted Flycatcher migration seems to have stalled in the cooler northerly airflow that we have been experiencing. There might be a window in the weather after early rain on Sunday morning when fairly calm conditions are forecast on either side of the English Channel, but by early next week we will be back in northerly airflow again.

The forecast for northern Britain is a mixed bag with the early part of the week looking quite stormy at times. This could be good news for anyone heading north to catch up with Long-tailed Skuas, as the birds could be pushed close to the northern isles, they will almost certainly be accompanied by Pomarine Skuas too.

Nightjar by Neil Calbrade

Any still, clear conditions during the next week will also help any Nightjars that are on the move. Some birds are already back at their breeding sites but the BirdTrack reporting rate shows they will continue to arrive during the next couple of weeks. And of course, waders will continue to push north when conditions allow too. Wood Sandpiper and Temminck’s Stint are good mid to late May birds to look out for.

Nightjar BirdTrack reporting rate

Friday 13 May 2016

The easterlies blow their magic

Almost constant easterly airflow during the last week or so had the desired effect on bird migration and a sumptuous array of rare and scarce birds arrived our shores.

Black Terns can be a bit hit and miss, but this spring, so far, there has been a steady migration of them through the country, drifted west by the easterly airflow. The BirdTrack reporting rate graph shows this beautifully.

Joining the Black Terns were a couple of Whiskered and White-winged Black Terns, completing the "marsh tern" set. Most records were from the Midlands, where wader passage also noticeably picked up. Several summer-plumaged Grey Plover, Little Stint and Curlew Sandpiper were found at wetland sites such as Swillington Ings, West Yorkshire or Rutland Water, Leicestershire.

Black Tern by Graham Catley / BTO

Warblers also appear to have taken advantage of the conditions and finally made it back to their breeding sites. Blackcap, Chiffchaff, Reed and Sedge Warbler all exceeding their historic reporting rate on BirdTrack. Reed Warbler especially showed a much higher reporting rate than usual in the second week of May.

Rarer migrants have also a distinctly eastern or south-eastern feel to them with Eastern Bonelli's Warbler, Caspian Stonechat and Calandra Lark noted in recent days. Grey-headed Wagtails on their way to breeding grounds in Scandinavia have also been noted at several east coast sites, as were the first Wryneck, Red-backed Shrike and Bluethroats.

A Dalmatian Pelican found in Cornwall last Saturday looked for a while like it may have been a genuine wild bird, having over-shot its breeding grounds in the Balkans. However, careful comparison of feather details with other Dalmatian Pelicans noted in northern Europe in recent weeks shows an almost much more interesting scenario. First seen in Poland, it was later tracked at a number of wetland sites in Germany and France, continuously moving westwards. Although it now seems likely that the bird escaped or was released and has been journeying across Europe.

Dalmatian Pelicans by Rod Calbrade

Spring migration isn't over yet. Nightjar has just begun to arrive and Spotted Flycatcher should peak in the next week or so, weather permitting. There is also still plenty of time for it to be a Quail year; these wonderful little birds can arrive throughout May and June, and the latter half of May is also the time we would expect skua passage to peak. Arctic and Pomarine should be possible off all coasts, while those in western Cornwall, Ireland and north-west Scotland could also be lucky enough to see one or two sunning adult Long-tailed Skuas moving north.

As of this afternoon, a cold front is moving south through Britain bringing a return to cooler northerly winds to all areas over the weekend. However, a southerly or south-westerly airflow may resume from early next week which should bring a few more migrants with them. Red-footed Falcons numbers have been building steadily in central Europe in the past week and is one to look for on your local patch.

Paul Stancliffe and Stephen McAvoy