Tuesday, 30 April 2013

Terns arrive!

Since St Patrick’s Day, Sandwich Terns have been reported along the Co. Dublin coast. These have been supplemented by reports of small numbers of Common, Arctic and Little Terns from about the start of April onwards. My own first summer migrants of the year were two Sandwich Terns on the Merrion Gates spit on the 28th March. This BirdTrack graph shows that Sandwich Terns’ arrival hasn’t been affected by the prolonged period of easterly winds and the cold temperatures that played havoc with this year’s spring migration schedule.

The percentage of birders' list in Britain and Ireland
that include Sandwich Tern. Source: BirdTrack.net
Despite the slow start, the delayed hirundines and warblers have been flooding in recently.  The rest of the terns will join us shortly, and it won’t be long before the tern colonies in Dublin Port, Rockabill and Dalkey Island are once again in full swing! 

Changing of the guard....

Signs of the changing seasons have been evident in Dublin Bay over the past few weeks, even if we had to wait a bit longer for the corresponding change in temperature! The wader numbers continue to fall, as most head off to breed in more northerly areas, and the terns are starting to arrive to take their place.

Despite the decreasing numbers, re-sightings of the marked birds continue to come in. Seven colour-ringed birds were reported in a flock of about 100 at the north end of Sandymount Strand on the 19th April. Unfortunately, they were disturbed by dog and flew off before the inscriptions could be read, but the information is useful all the same. In the same area on the 25th April, four more inscriptions were read from a small foraging flock. Another one of our birds was seen on Dalkey Island on the 23rd April. It seemed to be paired to another bird and was apparently prospecting for a nest site. 

These reports bring us up to 160 re-sightings of 87 individual birds, which really is fantastic progress in such a short time! A sincere thanks to all those who are taking the time to put in some ring-reading effort to help us piece this story together.

Friday, 26 April 2013

Dublin Bay Godwit drops by Scotland

A flock of Black-tailed Godwits, that spent the winter 2012/13 near North Bull Island in Dublin Bay, included a very special bird.  Photographed at least three times by Cian Merne, Richard Nairn and John Fox, it had a selection of colour rings on its legs.  It turned out that this bird had been marked by a Scottish ringer, Raymond Duncan, at the Montrose Basin, between Dundee and Aberdeen on the north-east coast of Scotland.  It had been caught as a juvenile, only a few months old, on 16th September 2012, not long after it had left its breeding grounds in Iceland.  With its new colour combination of orange and blue rings, EX71920 flew south to Dublin Bay where it was first resighted in December by Christer Persson at the Santry River.   A day later it was seen in Lein Park Raheny before moving with the flock to feed near the Bull Wall until at least March.  By May 2013, it would be back in Iceland after a flight of at least 1,500 kilometres, which it could have undertaken in one day. We will be looking out for this bird again next winter in Dublin Bay

Black-tailed Godwit flock with colour-ringed 
bird at North Bull Island. Richard Nairn

Friday, 12 April 2013

Let the ring-reading begin!

I spent a day last week trudging around the parks, pitches and beaches of Dublin looking for colour-ringed Oystercatchers, hoping to read as many rings as possible, knowing that it’d be one of the last chances I’d get before they head northwards to breed in the coming weeks. I was well prepared for the cold weather, but it turned out to be a very pleasant day with good spells of bright sunshine, which made ring-reading a joy. I managed to get 32 rings over the course of the day, including some that hadn’t been read before.

These colour-ringed birds are now individually recognisable and their rings can be read with a telescope or camera from hundreds of metres away (i.e. without the need for recapture). This allows us (and you) to record the movements of the birds throughout Dublin Bay and beyond. An analysis of these movements will allow us to determine key foraging and roosting areas in Dublin Bay as well as unlock mysteries about how birds are affected by things like disturbance and adverse weather.

The re-sighting effort began the day after the catch day (see March post), and since then, we’ve notched up a total of 123 re-sightings. Thanks to numerous enthusiastic ring-readers, 87 out of the 119 colour-ringed birds have been re-sighted. While the majority of these have been in the vicinity of the ringing site on Sandymount Strand, a small number of birds have been recorded numerous times on various parks and pitches in south Dublin. Early indications suggest that some birds have St. Michael’s College rugby pitches in Ballsbridge on their daily itineraries, while other birds seem to head elsewhere for their earthworms. It’s up to you to fill in the gaps on this!

The remainder of the wader roost at the Merrion Gates spit that 
held thousands of waders during the winter. Richard Nairn

We’re calling on you to make a special effort to read the inscriptions on these rings and report them to us. Even reports of colour-ringed birds where the inscription could not be read are useful. Although wader numbers are really dwindling in Dublin Bay at the moment, as birds head off to breed, there’s still some time to tick off another couple of colour-ringed individuals.

With this type of project, there really is no such thing as too much information! The benefit of having 119 individually recognisable Oystercatchers in Dublin Bay cannot be underestimated - these birds can tell us so much about what they do, what they need and how we can effectively protect and conserve them. But a solid database of re-sightings is the foundation on which everything else can be built.  

I was delighted to see the re-sightings flying in as soon as the project was launched on the BirdWatch Ireland website, so keep up the good work! It’s great getting all the re-sightings into the database and generating the re-sighting reports for each of the birds. At this stage, the “re-sightings histories” that we send to ring-readers only go back a number of weeks, but we have to start somewhere! With plenty of ring-reading, these re-sighting histories will become more and more interesting!

Three colour-ringed Oystercatchers on Sandymount Strand. John Fox

I think there is something very intimate about knowing the movements of individual birds around my local parks and beaches. But perhaps more importantly, reading the rings on these birds makes a contribution to conservation science and allows us to learn about how these birds use Dublin Bay and how we can work to ensure that they always will.