Thursday, April 7, 2011

We have been inundated yet again with Willow Warblers, with the day tally again breaking the 400 mark. Smaller numbers of Blackcap and Chiffchaff have also moved through and the first Yellow Wagtail, Redstart, Sedge Warbler and Grasshopper Warblers of the year were logged. Hirundine passage has stepped up a gear with over 200 each of Swallow and Sand Martin. The highlight of today came in the form of a Marsh Harrier which swept across the plantation and over the mountain as we were ringing at Nant.

Sadly my camera was set completely wrong when I grabbed it. But there is still enough here to see that this is a sub-adult male. The 'cream crown' plumage is still well in evidence on the head but the underwings and tail are the silvery colour of a male and the black wingtips are well defined. This is only the 31st record for Bardsey. (c) Richard Brown

Willow Warblers and Blackcaps are being attracted to the lighthouse almost every night at the moment. Sadly the death count continues to be quite high. A Wood Pigeon was also killed last night. (c) Richard Brown

The dark nights have meant that our most abundant breeding bird has started to come ashore in huge numbers. But the Manx Shearwater will not start laying eggs for another three weeks or so. They are currently coming ashore, very noisily, to reaffirm their pair bonds (the majority of Manx Shearwater pair for life) and to prepare their burrows for the breeding season (the majority of pairs use the same burrow each season). On islands where ground predators are absent (such as Bardsey), the only real threat to a breeding seabird comes from other birds. There is thus a distinct advantage to nesting in burrows as the nest is hidden away from aerial predators. Manx Shearwater can therefore take their time with rearing their chick, indeed the incubation period is approximately 51 days and the chick remains underground for about another 71 days after that. So living underground would seem danger free...

...but not always! This Manx Shearwater must have moved just the wrong piece of soil or stone as it cleared a burrow for the coming season. (c) Richard Brown

It's not only birds that are on the move. The Dark Sword-grass (above) is an immigrant to Bardsey. The majority of the catch at the moment is made up of Red Chestnuts and Common Quakers (below). (c) Giselle Eagle

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