Tuesday, 8 March 2016

Dublin Bay Oystercatcher: an Oransay regular

One of our Dublin Bay Oystercatchers is becoming a regular on Oransay in the Inner Hebrides. Morgan Vaughan, RSPB warden up there, tells us about how he crossed paths with Oystercatcher “UA”.

I am fortunate enough to carry out a WeBs survey for the BTO which falls within the South Colonsay and Oronsay SSSI, Argyll, Scotland. The two inner Hebridean islands are separated by a tidal strand and this is where I carry out the monthly survey as part of the monitoring work as warden of RSPB’s Oronsay. I tend to count on a rising tide shortly after low water as this pushes the waders out from the skerries of the islands peppered through the strand to feed along the water’s edge. This also gives a readily countable stretch of sand to work along. The intertidal zone is flanked by costal heath, maritime grassland and salt marsh, all of which granted protection for chough, corncrake and grey seals.

Colonsay and Oransay and the intertidal area
where Oystercatcher "UA" hangs out

During the March count (16/03/2015) last year, I spotted a colour-ringed oystercatcher close enough to get the colours and I could see that there was an inscription on one of the yellow rings, but it was just too far away to make out. I returned eagerly the next day with camera in hand and managed to find the bird again in the same spot and snapped a usable photo. UA.

Oystercatcher "UA" foraging on the sandflats
between Oransay and Colonsay
Morgan Vaughan

I’d worked out on the day that it could be potentially a Dublin Bay bird and with great excitement I fired the photo off to Niall Tierney who promptly informed me about the bird’s history; “The bird was caught on the 22nd November last year [2014] and has only been seen once since then, on the 27th November, back at the ringing site”. I’m always so pleased with a result like this. Finding out the history of a ringed bird, especially an international traveller is always marvellous!

I kept a close eye while surveying our breeding waders on Oronsay for any other oystercatchers with rings, but no sign of UA. I’m always on the look-out for rings, a minor obsession borne out of my work with colour ringed chough, but I had no further sightings on the strand.

Oransay landscape Morgan Vaughan
Nearly a year on (23/02/2016), I’m on the strand again, counting on the incoming tide, and there’s UA once again - close enough to make out with the eye!  It is fascinating to wonder where this bird has been for the last 11 months. Perhaps it has been breeding somewhere nearby. I will be certain to be on the watch for it again during this year’s breeding season.

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