Migration blog (7th May - 13th May)

With the weather over the last seven days being typical for the time of year, migration was a bit of a stop-start affair, with showers causing some species to land and sit out the damp conditions. The first good arrival of Wood Sandpipers was noted with several birds reported from across the country, but with a bias from the Wash northwards. This dainty, long-legged wader is much prized by inland patch watchers and can be found on large reservoirs to semi-permanent pools in cattle fields and everything in between. Another wader that also occurred in increasing numbers was Dotterel. This upland specialist can sometimes be found in newly ploughed fields, or on short turfed areas from the coast to inland and again is much sought after by many. Some groups, or trips as they are sometimes referred to, were found in Norfolk and Yorkshire, and some were also identified from nocturnal recordings.  As with some other wader species it is the females that are the more brightly and strongly marked of the sexes. 

For some, House Martins have been conspicuous by their absence, but the last week has seen them arrive across many parts of Britain, although some places still seem to be missing them. During these lockdown conditions it is difficult to use the BirdTrack reporting rate graphs to detect any drop in occurrence for House Martins as they are biased by people submitting sightings from their homes rather than the sites they would traditionally be visiting during this time of year. 

The past week also saw a good arrival of Whinchats with birds reported right across the country, Spotted Flycatchers which are typically a late arrival, and Pomarine Skuas, especially along southern and eastern coasts.

Again, the odd rarity was mixed in with the pick of the bunch - one, or possibly two Squacco Herons were found in Durham and East Yorkshire. Subalpine Warblers were found in Wales, the Shetland Isles and on the Isles of Scilly, and Bee-eaters reported in both Pembrokeshire and Kent.

Species focus - Whinchat

The main arrival time for Whinchat in the UK is from mid-April to early May, with some birds still on migration beyond mid-May. Spending the winter months in the Sahel, it is thought that birds heading back to the UK to breed take a more easterly route across the Mediterranean than that taken in the autumn, which appears to be through Spain and Portugal.

Whinchat breeds as far north as northern Scandinavia and during easterly airflow in both spring and autumn birds heading to northern Europe can get drifted across the North Sea, often resulting in falls of Whinchats on the east coast of Britain.

Between 1995 and 2017 the Whinchat breeding population in the UK fell by 56%, resulting in it being red-listed as a bird in need of conservation action. The current population estimate is around 50,000 breeding pairs, mostly in the upland margins of Scotland, northern England, central Wales, Exmoor, Dartmoor and the Isle of Man. The only significant lowland breeding population is on Salisbury Plain.

From Sunday there will be a distinct change in the weather, with a drop in temperature of around 10-14 degrees for some, as high pressure centred off Southern Iceland drags in cold northerlies straight from beyond the Arctic Circle.  

Weather for the week ahead

As we head towards the Bank Holiday weekend, temperatures build during Friday and Saturday with long spells of sun forecast for many. This will allow birds to continue their migration and should see wader numbers increasing. This is the peak time for Dunlin spring passage. There are several races of Dunlin, and in Britain and Ireland at this time of year up to three races can occur: schinzii, which breeds in Britain and Ireland, alpina, which breeds in Scandinavia and Siberia and is predominantly a winter visitor, and finally arctica, which winters in West Africa and passes through the UK at this time of year on its way to breeding grounds in Greenland. It is worth checking Dunlin flocks at this time of year because there can be the occasional Curlew Sandpiper, Little Stint or Temminck's Stint mixed in, with Curlew Sandpipers attaining their distinctive brick-red summer plumage. Other waders passing through Britain and Ireland at this time of year include Turnstone on their way to Greenland or Russia, Grey Plover heading to Siberia and Ringed Plovers that could be heading either west to Greenland or east to Russia.

Raptors will be taking advantage of the settled conditions on Friday and Saturday and both Hobby and a few Honey-buzzards are likely to arrive. Both are localised breeders in the UK, but could also be overshooting from Europe. Scarcities that could be found include Black Kite, Bee-eater, White Stork, Black Stork, and Golden Oriole.

From Sunday there will be a distinct change in the weather with a drop in temperature of around 10-14 degrees for some, as high pressure centred off Southern Iceland drags in cold northerlies straight from beyond the Arctic Circle. This cold snap should only last a couple of days with temperatures beginning to recover from Tuesday onwards, but during this cold spell, migration is likely to be put on hold for the majority of species as they sit out the adverse conditions. The brief period of colder weather shouldn't have too much of a negative effect on those migrants that have already arrived, as they would have had time to replenish the fat reserves they burned up whilst migrating, and there should still be enough food around to see them through. The high pressure responsible for the cold winds will sink further south and, as it does, so the wind direction will swirl around in a clockwise direction across the UK with North westerlies for Scotland and Northern Ireland and Easterlies for the rest of the UK. After the weekend few birds will be on the move but it should give you a chance to take stock of what has already arrived and could be laying low during the cold snap. The good news is the weather for the following weekend and onwards is looking much better and could yield some nice surprises.