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.

Thursday 24 March 2016

The floodgates are ajar

The cold northerly airflow has been holding things up during the last week but with lighter winds during the last couple of days some birds have managed to get through.

Several sites along the south coast have enjoyed double figure arrivals of Wheatear. Portland, Dorset seems to have seen the best of this with 60 being counted there on the morning of 22 March. Sand Martins have continued to trickle in but numbers remain small, similarly Swallows have been arriving but are still very thin on the ground, and one or two more House Martins have also been seen.

Sand Martin reports via BirdTrack

Garganey arrived in small numbers but on a broad front with birds being reported from several counties during the week. The largest movements seen this week involved Meadow Pipits arriving and then moving along the south coast. Several hundred birds were noted moving through on a couple of days.

Late arriving: Wheatear

As one set of birds arrives, another set is departing. Redwing and Fieldfare have been recorded, at times in quite large flocks, as were flocks of migrating Starling. Geese were on the move as well, with northward bound Pink-footed Geese amongst others noted in Scotland. Woodcock were found at several coastal sites.

Redwing moving through

The most intriguing migrant this week was probably the Blue Tit trapped at Sandwich Bay Bird Observatory. It was found to have been ringed in Lithuania and had good muscle and fat scores, presumably to fuel the outgoing migration back north and east. Keep an eye on the BTO's Demog blog on this and other ringing related stories.

The Met Office surface pressure charts show potential for some south to south west winds extending from northern Spain across France to southern Britain from Friday onwards. This ought to result in a fresh wave of arrivals from the south, and allow any migrants wanting to attempt the crossing of the North Sea to have a go.

Likely new arrivals next week include the first Willow Warblers and Blackcaps, as well as more Wheatears and Sand Martins. Given the stormy weather conditions, there may even be local "falls" of migrants. Rarer migrants to keep an eye out for in late March and early April include Purple Heron, Alpine Swift and the even rarer Great Spotted Cuckoo!

Purple Heron (Graham Catley)

 Paul Stancliffe and Stephen McAvoy

Friday 18 March 2016

Migration blocked

The high-pressure that is currently sitting over most of the British Isles is producing fronts along its flanks and a predominantly north-easterly airflow that is pretty much blocking migration from further south. The relatively light winds, at times, have let a few migrants through but it has very much been a trickle, not a flood.

Sand Martins, Wheatears and Chiffchaffs have arrived in small numbers and there has been one or two Swallows arriving with them but even with this arrival things are very slow. Looking at the weather charts for the next few days it looks like things aren’t likely to change very much.

Chiffchaff by Amy Lewis

All of the BTO satellite tagged Cuckoos have now left the Congo rainforest, four are in West Africa and three are in the Central African Republic. We expect the first of them to cross the Sahara in the next week or two.

Blackbird by Jez Blackburn

Going north, birds have definitely been on the move. The number of Whooper and Bewick’s Swans are falling rapidly, Pink-footed Geese have been seen over the Pennines in good numbers, and ringers have seen long-winged Blackbirds with high fat scores in gardens in the east, birds that could be crossing the North Sea any day now.

Although the forecast isn’t looking too promising there will be a period of light east, north-east winds over the Channel on Sunday/Monday, and they might just be light enough to allow any birds that are held up further south to move. If this is the case, it will be more Sand Martins, Wheatears and Chiffchaffs, with maybe a few Ring Ouzels, Garganey and Swallows thrown in.

Thursday 10 March 2016

Kittiwakes moving through

The cold northerly and westerly winds during the last week or so have pretty much put the brakes on the arrival of any early summer migrants. However, a small number of hardy individuals did make it here. At least three Sand Martins have been seen in the last week - the first at Frampton-on-Severn, Gloucestershire on the 5th March followed by further singles in Glamorgan, West Midlands and Carmarthen. An Osprey was notedin Cheshire, two Stone Curlews back on their heath in Suffolk, and a handful of Wheatears were reported from scattered sites in the south.

Wheatear (Moss Taylor)

Much further south, House Martins, Swallows and the first Pallid Swifts are back on their breeding territories in southern Spain. Black Kites and Short-toed Eagles have been seen leaving North Africa and crossing the Straits of Gibraltar. The BTO-tagged Cuckoos are also moving on from their winter territories and are beginning to head north to make the perilous journey across the Sahara. Spring is coming.

A feature of the last week has been the surprising number of Kittiwakes spotted at inland sites across central and southern England. The majority of records involved single birds on larger lakes and reservoirs, but three were noted at Calvert Lakes in Bucks and two even visited the BTO's Nunnery Lakes reserve on the 3rd March. The day before 150 had been seen from Severn Beach, Gloucestershire. Could these birds (and more) have followed the Severn upstream and then moved broadly east towards the North Sea?

Kittiwake on the Nunnery Lakes (Stephen McAvoy)

Although the weather might have stalled spring migration so far, it looks like there may be a change on the cards over the weekend and early next week with some southerly winds forecast. It is still early in the season, so the floodgates aren't likely to open just yet. A few more Chiffchaff, Wheatear and Sand Martin should arrive, along with perhaps the odd Swallow.

Paul Stancliffe & Stephen McAvoy