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 28^th 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 19^th 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 25^th April, four more inscriptions were read from a small foraging flock. Another one of our birds was seen on Dalkey Island on the 23^rd 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.

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 16^th 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

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.

BANG!! The Dublin Bay Birds Project is well and truly underway.

On the 26^th February, a team of BirdWatch Ireland ornithologists and volunteers were joined by members of the Highland and Grampian Ringing Groups to catch and colour-ring Oystercatchers at roost near Merrion Gates. We arrived on site at 06:30 to set the cannon-nets at the tip of the newly formed spit between Booterstown DART Station and Merrion Gates on Sadymount strand, Dublin. The idea is that the rising tide pushes the birds up the beach towards the cannon-net, and it gets fired over them as they roost. We expected that they’d be in position around high tide, which was at 11:47. And so the stakeout began....

While the licenced cannon-netters took up the best viewing positions, the rest of us kept well back to ensure we didn’t disturb the birds are they foraged ever closer to their roosting position on the spit. We couldn’t see what was happening at the catch site and relied on the cannon-netters to keep us informed via walkie-talkies.

While we couldn’t complain about the weather, as it was dry and bright, all those layers of clothes were needed as we sat on the cold sand. We kept ourselves warm with coffee from our flasks and tried not to tempt fate by talking about how many we’d catch. 

The catch team. Sinéad Cummins

We were keeping our heads down and couldn’t see what was going on, but we knew that the encroaching waves would be eating up the remaining foraging area and pushing the birds towards their roosting position, and the catch zone and that we could be called into action at any time. Tension mounted. If the birds weren’t in the catch area when the tide reached its summit, we knew we’d have to stand down and try it all again tomorrow.

However, as high tide approached, the radio chat was positive and a wave of anticipation swept around our small group. That is, until we heard that three Oystercatchers had marched up the beach and roosted right in front of the net. This meant that the net couldn’t be fired as they birds weren’t in the safe zone. Could these three birds have inadvertently ruined weeks of meticulous planning? Would we have to call the whole thing off and wait until tomorrow? Luckily, those three didn’t fancy roosting there and wandered off after a while, meaning the possibility of a catch was back on  ...but there were still no birds within the catch area.

As high tide approached and the radio chatter became more and more pessimistic, we began thinking about getting back to the office and getting to all those other jobs that this cannon-netting has superseded.

...Then something happened - I still don’t know what, and a portion of the birds moved into the catch area. Now it was up to the cannon-netters to pick their moment to fire the net over the roosting birds. As we scrambled to put lids on our flasks and load ourselves up with the ringing equipment, we heard the words over the radio that we’d been waiting for all day: “firing in ...three, two, one!”

BANG!! Suddenly we were all scrambling to get ourselves and gear to the catch site. Moments later the holding pens had been erected and the birds were being taken from under the net. The ringing table was set up, the various tasks were allocated and we began to process the birds.

We caught 119 Oystercatchers and a Ringed Plover. Each bird was ringed with a BTO metal ring (see BTO ringing scheme here) with a unique number and address. In order to determine body condition, a series of measurements were taken (wing, tarsus and bill length and weight). Each bird was aged using plumage details and the colouration on the legs, bill and eye. Finally each Oystercatcher was fitted with a series of plastic colour-rings to give each bird a specific identity.

Colour-ringed Oystercatcher "IV"  Richard Nairn

A special thanks to all the volunteers who gave their time to get this aspect of the project off the ground. Every pair of hands was needed to ensure that the birds were caught, processed and released promptly and without any problems. But the voluntary help doesn’t end there! We’re calling on all birders to make a special effort to read the inscriptions on the rings before the birds leave our shores to head off to breed.