Friday, June 17, 2011

Yet another run of migrant free days has really made it feel like spring is over, but we are still very busy monitoring our breeding birds. Six young Blue Tits are in the Obs garden (since the Obs was founded in 1953 only one Blue Tit has fledged, at Nant in 1989) and fledged Willow Warbler are in Cristin Withy, the Obs garden and at Nant (this species has only bred nine times in the same period). The severity of last winter must have played a big part in the decline in numbers of our commoner breeding landbirds but productivity seems to be very good in the most-part and the gardens are alive with the calls of young Dunnocks, Wrens, Pied Wagtails, Robins, Chaffinches and Blackbirds. Elsewhere fledged Meadow Pipits, LinnetsWheatears and Stonechats are conspicuous. The first fledged Peregrines and Chough have now joined the fledgling Ravens on the thermals above the mountain. A few of our landbirds are yet to fledge young but it is looking like this wont be the case for long...

Both Whitethroats and Sedge Warblers are currently feeding young. There are more pairs of Sedge Warbler breeding than ever before and Whitethroats are back up to four pairs after a few lean years. (c) Richard Brown

Gannets, the largest indigenous seabirds in the Western Palearctic, do not breed on Bardsey, indeed the closest colony is probably Grassholm in Pembrokeshire where about 30,000 pairs breed. But we do see them in varying numbers virtually every day around our shoreline. Today they were fishing close inshore whilst we were counting Oystercatcher territories. (c) Richard Brown

It was great to spend time watching the Gannets fish. They were working in a short circuit, doubling back after a dive to scan what was proving a productive area of sea. It was obvious when a bird had spotted its target, their heads fixing a point in the water as they flew. Gannets have their eyes positioned far enough forward on their faces to give them binocular vision which helps to accurately judge the distance to their prey. After fixing a target, their heads remained near motionless as their bodies cartwheeled around above them to start the dive. (c) Richard Brown

Gannets can dive from up to 30m above sea-level and reach speeds of up to 100km/h as they strike the water. They have special adaptations to deal with this fishing technique including air sacs positioned under the skin of their face and chest which act as a cushion when they impact the water and an absence of external nostrils to stop water from being forced into their lungs. (c) Richard Brown

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