Friday, 18 March 2016

Next stop Iceland for these leggy beauties!

Dublin Bay hosts internationally important numbers (that is to say that more than 1% of the flyway population) of Black-tailed Godwits each year. From late summer, normally towards the end of July, Blackwits begin to arrive back to Ireland from Iceland. It is often the failed breeders that arrive first, with the breeders and the juveniles coming slightly later on. They tend to arrive quite suddenly to Dublin Bay. Our first July count last year amounted to 159 birds, but this had doubled by our next count, ten days later. We get an autumnal peak (7 or 800 birds) in Dublin Bay in September, but the flocks soon disperse. Then, as the winter progresses the numbers gradually grow before peaking at about 1,500 birds in March and early April. And by May, they’re gone.

Flock of Black-tailed Godwits in springtime Liam Kane

Right now Black-tailed Godwits are focused on feeding up and getting in condition for migration in the coming weeks. But they also need to get plenty of energy on board to fuel a complete change of their body feathers. Many have started this spring moult, which effectively is them putting on their glad rags for the breeding season. They will transform from a palette of grey into vivid burnt orange on the head, neck and chest with the flanks and belly strongly barred, the wings held closed have coarsely spotted orange, white and black feathers amongst mainly grey white fringed feathers.

Springtime in Dublin Bay presents the fantastic opportunity to observe these beautiful birds as they transform into their summer finery. An international team of Godwit researchers  are keen to investigate the regional differences in the timing of moult - some of the birds that winter in Portugal start their moult earlier than our birds up here. They are looking for your help to piece this story together. Read more about this on Wadertales - a fantastic wader-focused blog, which is definitely worth checking out.

A colour-ringed Black-tailed Godwit was recently spotted in the South Lagoon on Bull Island. This bird was originally ringed as a juvenile bird in the Montrose Basin in north east Scotland in 2012, and is now a regular to Dublin Bay. We have become very familiar with this bird over the past few years and have followed his movements around Bull Island and the surrounding parks and pitches. You may remember him being mentioned on our blog previously; find out some more about this guy here and here.

Colour ringed Black-tailed Godwit Richard Nairn

With the Black-tailed Godwit regional moult survey fast approaching, why not get out to your local patch and see how your Blackwits are looking? It would be really interesting to see where the Black-tailed Godwits wintering in Dublin Bay sit within the international moult trend. The coordinated observation period is the Easter weekend - the 25th and 28th of March. Read the full instructions and all the details on the Wadertales blog. 

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.