Saturday, 18 March 2017

Colour Ringed Oystercatchers

Since Autumn 2015, all oystercatchers caught in Pembrokeshire have been colour-ringed. Most of the 38 that have been ringed so far have been caught at the Gann, with six ringed on Skokholm and one at Sandy Haven. Of these, 17 have been subsequently seen again involving 44 resightings in total. The commonest scenario by far is to see birds back at the same site as they were ringed, though there is clearly a link between The Gann and Skomer/Skokholm with six individuals moving between these sites. So far only two have been recorded outside of Pembrokeshire "A1" and "04";

"A1" was ringed at The Gann on 14/03/2016 and was seen on Tiree on 13/03/2017.

"04" was ringed at The Gann on 16/10/2015 and spent the summer at Stranraer, before returning to the Gann on 11/08/2016.

"A4" was also ringed at the Gann on 14/03/2016, and was seen on Skomer on 21/07/2016 and again there on 16/03/2017.

Oystercatcher resightings from birds ringed at the Gann
There's a lot to be discovered about this declining species, and any resightings will be very gratefully received (see contact form in the side bar). The Pembrokeshire scheme has a plain orange ring over the metal on the left tarsus and an inscribed orange ring with black digits/letters reading upwards on the right tarsus, as shown below.

A0 about to be released


Monday, 6 March 2017

An Average Winter for Woodcock

Maybe it's part of getting old, but its puzzling why there is a tendency to feel that previous years were somehow better in some way, with either endless sunshine or, in the case of bird ringing, hundreds of birds, all of which were easy to catch. When asked how the season had gone for woodcock this winter, I have said on a few occasions "not very good". To be fair, there were a few nights in January which were very unproductive, resulting in only six birds ringed from five nights' effort, and this experience must have negatively influenced morale, giving a feeling of gloom. The winter of 2016/2017 is now almost at an end in terms of available lamping sessions, because most of the woodcock will have started to move back east before the next period of dark evenings from 16th March, so lets see how bad it really was.

Well, in terms of ringing totals from the central part of Pembrokeshire, this winter has been slightly above average for woodcock, but for all other species that roost in pasture at night, the totals are lower than usual, though most are typically only found in small numbers anyway - see table below. The exception is snipe which is often seen in good numbers but is very difficult to catch.

  Total Individuals caught
2016/2017
Average for winters
2008/09 to 2015/16
Fieldfare 1 5
Golden Plover 3 6
Jack Snipe 1 1
Meadow Pipit 5 10
Redwing 2 4
Skylark 2 6
Snipe 4 7
Woodcock 101 89
Total 119 128




During ringing visits counts are also made of all woodcock seen, regardless of whether they are ringed or not and this enables a more reliable comparison of the encounter rate, which is perhaps a better indicator of actual numbers because catch rate varies enormously with weather conditions and the brightness of the sky. In Pembrokeshire catching is often best when there is at least some wind, under thick, low cloud or (surprisingly) no cloud at all when every star is visible. High or scattered cloud makes a bright sky due to light pollution, especially on the horizon, and in such conditions, woodcock often fly before close approach can be made. Having said that, the average encounter rate based on 161 field visits was 0.55 per hectare, 10% above the combined average for previous winters since 2008/09 (0.50), so in this case the slightly higher field counts agree almost perfectly with slightly higher ringing totals. Not so gloomy after all!
Woodcock roosting in pasture. Photo: Myles Jenks