Polar plunge will slow spring migration

Eiders in the Menai Strait (Jonathan Bull)

The sharp drop in temperature will be a shock to hungry migrant birds arriving from Africa, and the insects on which many depend. It may also hinder resident birds that are already nesting, including those such as Mistle Thrush, Grey Heron and Dipper that have hatched young by early April.

Ahead of the northerly winds, migrants had been streaming in. Huge numbers of Sand Martins fed over Anglesey’s Cefni Valley last week, with smaller numbers of Swallows and House Martins, and Pied Flycatchers have been seen in several woodlands across North and Mid Wales. Other migrants seen this week include Whimbrels, Tree Pipits, Ring Ouzels and Common Sandpipers. Several Ospreys were spotted in local airspace, and a remote microphone recorded a Stone-curlew over Penrhyn Bay, a rare bird in Wales.

The RSPB’s Cors Ddyga nature reserve was filled with the calls of Curlew and Golden Plovers on Sunday morning. More than 200 of the plovers fed in the pools, many in their striking black-and-gold plumage ready to nest as soon as they arrive on the Icelandic, Greenland or Faeroese tundra. They shared the reserve with many White Wagtails also heading to Iceland, and several Little Ringed Plovers. Skylarks’ powerful song mixed with the falling cadence of freshly-arrived Willow Warblers, and early visitors heard the deep boom of Bittern. Earlier in the weekend, I’d counted 180 Eider ducks off Penmon Point, the largest number I’ve seen in the Menai Strait.

In Mynydd Hiraethog, a Black Redstart was on the dam at Llyn Aled Isaf on Sunday, a Scaup on nearby Llyn Brân and two Little Ringed Plovers on Llyn Brenig, where a pair of Ospreys has been seen. A Surf Scoter was off Llanddulas at the weekend, another close inshore off Talacre, and the wintering Iceland Gull remained at Rhyl’s Brickfields pond to Sunday, at least.

A new national avifauna, The Birds of Wales, will be published in July. Liverpool University Press is accepting pre-orders for £25 (plus p&p), which is £20 below the published price. Click here for details and to order, using the code WALES50 to get the discount.