Familiar Faces

As the Dublin Bay Birds Project approaches its second winter, we are getting reacquainted with our colour-ringed waders. As well as getting to know the individuals, their haunts and habits in Dublin Bay, we are also beginning to see the real benefit of our ringing efforts. Our birds have been reported from as far away as Scotland, Iceland and Norway.

Bird ringing is not a new technique by any means, but it is a hugely effective tool in the conservationist’s tool kit. Not only does it allow us to build a picture of bird movements locally and internationally, but when we catch (or re-catch) birds, it allows us to collect biometric data and assess their body condition, which aids our understanding of the species, and ultimately leads to more effective conservation.

While colour-ringing (and subsequent re-sightings) generate valuable data, we are also fitting a subset of the birds with radio-transmitters in order to get a finer level of detail. The first of the radio-transmitters were deployed last January , and a mammoth radio-tracking effort followed. We collected some high resolution data on eleven radio-tagged birds, both by day and by night, during high and low tides.

 Radio-tracking continued into the spring, and by early April, we could no longer pick up the signals from any of the Oystercatchers or Bar-Tailed Godwits. The last of the Redshanks stuck around until the last week in April, before heading north into the unknown. 

Helen and Niall Radio tracking last winter

Out of sight, but never out of mind, we focused on terns for the summer months. But the colour-ringed and radio-tagged birds were never far from our minds: where were they breeding; had a winter feeding on Sandymount Strand allowed them to get into breeding condition; did they breed successfully; when would they arrive back in Dublin again?

Oystercatcher re-sighting locations (red)
Oystercatchers ringed as Pulli in Scotland and colour ringed in Dublin (green)
Ringing location (blue)

We checked emails eagerly, waiting for news from birders and researchers from far away with unpronounceable names. With time, the emails trickled in from far off places…

Among the jet setters were Redshank "BH", who was re-sighted in Iceland’s western fjords  on the 18^th May, and Bar-tailed Godwit “DH", who was re-sighted in Finnmark, Norway a day later, on May 19th. Oystercatcher “CU” was seen (on a traffic island!) in Stokksetri in Iceland. His mate was subsequently colour-ringed as part of an Icelandic study. Who knows where she will spend the winter?

Redshank "BH" (yellow), Bar-Tailed Godwit "DH" (green) re-sighting locations
Ringing location (blue)

The database has almost reached 1,000 re-sightings, which is fantastic, and we’d like to sincerely thank everyone who has submitted records to date. These re-sightings are the life-blood of the project.

 

Of the 151 Oystercatchers that we ringed, 89% have been re-sighted at least once, and 66% of have been seen three times or more. Ten of them have been seen outside Ireland. Oystercatcher “FI" has been re-sighted in Dublin 23 times, and takes the crown for most regularly recorded colour-ringed bird. "FU" and "BC" come in at a close second, with 21 re-sightings each.

Redshank "AN" ringed and radio tagged John Fox

We were delighted to catch up with Oystercatchers, "NA" and "CH," and Redshanks, "AN" and "AP" in recent weeks. These guys have played a pivotal role in our data collection, as they carried radio-transmitters for us last winter. Great to see them back in Dublin again!

We are looking forward to the coming months and getting out and re-sighting more and more of our birds. We will continue to build a picture of their movements both within the bay and further afield. As always, we would love to hear from you and integrate your re-sightings into our growing database. It’s a great way to spend an autumnal day, and anyone can do it (but a scope or camera helps). If you do manage to get out and about, you can submit your sightings here.

Sandymount Spectacle

Annually, from mid-August onwards, Dublin Bay plays host to the avian spectacle that is the post-breeding tern aggregations. Sandymount Strand is a roosting hotspot for thousands of terns from four species. Common, Arctic and Roseate Terns make up the bulk, with Common Terns accounting for the vast majority. Most evenings, Sandwich Terns can also be observed too: you may not manage to pick one out from the crowd, but you'll most likely hear the loud grating kerrick kerrick calls of Sambos (to give them their cool name!) in flight. 

Sandwich Tern in breeding plumage Dick Coombes

It's not just birds that have bred in Dublin that are attracted to the Strand, but birds from the UK and further afield too. The fact that a small number of Black Terns, whose nearest breeding colony is in The Netherlands, are seen in the roost every year confirms that it's not just local birds that the roost supports. 

Mixed tern flock on Sandymount Strand John Fox

Dublin Bay provides an excellent food resource, in the form of small fish, in order to sustain the big numbers during this staging period. After feeding off-shore all day, the terns converge on Sandymount Strand in their thousands each evening. The numbers at the roost builds from mid-August to mid-September, until Mother Nature prompts them to set off southwards to spend the winter in west African waters, and even further to Antarctica, in the case of many of the Arctic Terns. 

Arctic Tern in breeding plumage Andrew Kelly

To avoid predation and disturbance, most terns tend to breed in out of reach places, such as off-shore islands, so this post-breeding aggregation offers a great chance to observe these beautifully delicate seabirds up close. The sheer numbers allow a fantastic opportunity to really appreciate these birds and to work on your ID skills! The best time to watch this spectacle is about an hour or so before sunset; and the higher tide the better, as the birds are pushed further up the beach.

Several roost censuses during this period allow us to determine the peak numbers and the species composition, and gives us an opportunity to assess the trends from year to year. So, if you see a couple of windswept guys staring in the direction of a large group of terns in the coming weeks, it's probably the Dublin Bay Birds Project team. Come say hello - we'd be happy to point out what's about and hear about what you've seen. 

Changing of the Guard

It's all change in Dublin Bay as the tern season comes to a close and the first good numbers of waders return south from breeding grounds in colder northern climes. The first returning waders tend to be non/failed breeders, followed by successful breeding birds and juveniles. The terns have raised their chicks (or failed, to as may be the case), and are now preparing to migrate south in the coming weeks.

It's been a reasonably good year for the Dublin Port terns with more Common and Arctic Tern nests than in 2013. Mild conditions and few extreme weather events will have helped their cause this year. Predation (probably by corvids) had some negative impact in the early season, but seemed to resolve when the full complement of adult Common Terns returned to breed and protect the colony. A nest count, on June 18th, gave 487 and 96 Common and Arctics, respectively. On the 11th June last year, there were 418 and 25 Common and Arctic tern nests.  

Common Tern chicks with some new jewelry Helen Boland

The terns will now begin to gather en masse in large mixed flocks across Dublin Bay in the coming weeks, with numbers peaking in mid-September. They will then trickle south, where many will winter along the West African coast.

On any given evening in September you will be able to witness up the terns roosting on Sandymount Strand. These species include Common Terns in very high numbers, good numbers of Arctic and Roseate Terns and handfuls of Sandwich Terns. You might also be lucky enough to to bag yourself a sighting of a Black Tern, which are annual visitors to Dublin Bay, en route from breeding colonies on the Continent. Our Little Terns leave directly after breeding and are rare in post-breeding flocks.

Post-breeding flock on Sandymount Strand Dick Coombes

As the tern numbers build, they are joined by waders that have bred further afield, and also by some scarcer visitors. Wood Sandpipers, Little Stints and Little Ringed Plovers are a few examples.

Our common wintering wader species will now begin to grow in number with flocks of Redshank, Oystercatcher and Bar-tailed Godwits getting larger by the day. Many of these birds will spend the winter here with a host of other waders, waterfowl and gulls. One such bird, Oystercatcher "BU," has already made his way home for the winter after being seen in Lossiemouth Estuary, Moray, NE Scotland on July 17th and again in Dublin at Merrion Gates Spit on July 30th.

Home to roost - "BU"s journey from Scotland

As always keep an eye out for colour ringed birds and we would be delighted to get your sightings reported. If you read any rings do report them to us here.

It's all turned terns at Dublin Port

On our last blog earlier in the month we were discussing colour-ringed wader re-sightings, but now the tern season is upon us, and its time to update you on the breeding terns in Dublin Port.

The annual breeding season monitoring started earlier this month, and the nest census revealed healthy numbers at the two subcolonies on the mooring dolphins in the port. We've made a few visits so far in order to count the nests and work out clutch sizes.

Common Tern colony on the ESB "Dolphin" in Dublin Port Helen Boland

Our first visit was all about nests and clutch sizes, and we recorded a total of 417 Common Tern and 66 Arctic Tern nests. Censusing the platforms is quite straightforward pre-hatching, as you're not trying to count mobile chicks, scurrying into the tiniest of gaps! During the visit we encountered a number of predated eggs, which, like last year, look like corvid depredation. The tern eggs had been snatched, brought to a safe (from mobbing terns) spot, and eaten by the culprit. It's a fairly natural occurrence in the early part of the season, and as tern numbers build, so does their capacity to deal with intruders.

Corvid predated Common Tern egg Richard Nairn

When rowing out to the colony, we saw a small number of adult Common Terns "belly dipping" in the water in an effort to dowse the eggs to keep them cool in the strong June sunshine. This is a behavior often exhibited by tropical tern species, such as White-cheeked and Whiskered Terns in warmer climes, as the eggs can over-heat and the chicks more or less cook inside the shell! People often think that when a bird is sitting on the nest that the sole purpose is to keep them warm, but in fact it can often be done to shelter the eggs or nestlings from overheating.

Arctic Terns will nest anywhere. Richard Nairn

Our second visit revealed an increase in nest numbers: 487 and 91, Common and Arctic Terns, respectively. A total of 315 chicks, 42 of which were Arctic Terns, were ringed. We counted 555 Common and 58 Arctic Tern chicks, but there were still some eggs, which will hatch over the next few days.

Common Tern chicks, ready to be ringed. Helen Boland

All in all, its turning out to be a reasonable year for the port terns. Mean clutch size is on par with their Rockabill peers.

We will continue to monitor the fortunes of the colony and report back soon on progress.

RW

Bar-tailed Godwit, DH, enjoys some midnight sun

Just a very quick one today, to mention our first Bar-tailed Godwit re-sighting outside Ireland. It turns out that this is also the furthest away that we’ve had a re-sighting!

Ringing and re-sighting locations for Bar-tailed Godwit, DH. 

While we managed to catch up with, and ring-read, 31 out of the 99 Bar-tailed Godwits (ringed 31^st Jan, 2014) before they left Dublin Bay, DH wasn’t read until the 18^th May, when it was photographed by Tomas Aarvak. Here’s a very dapper-looking DH in northern Norway, looking a lot more colourful than on the ringing day in January.

Bar-tailed Godwit, DH, in breeding plumage in Porsanger, 

Finnmark, Norway on 18^th May, 2014. Tomas Aarvak 

It won’t be long now before we start to see waders, most likely failed breeders, returning from the north, and there are also quite a few of the colour-ringed Oystercatchers and Bar-tailed Godwits summering in Dublin. So, if you feel like getting out there to do some birding or ring-reading, your re-sightings would be greatly appreciated!

     

Well Spotted!

Last night, Monday 19th May, we had one of our most interesting colour-ring re-sightings to date. Its the first Dublin Bay Birds Project colour-ringed Redshank that has been re-sighted outside of Ireland. In an extraordinary coincidence, the bird (colour-ring BH) was spotted by BirdWatch Ireland's very own Olivia Crowe whilst over in Iceland on a Knot ringing expedition, which is  co-ordinated by Jim Wilson as part of The International Wader Study Group.

The team was out late Monday evening attempting a cannon-net catch on a flock of 9,000 Knot in Iceland's westerns fjords, when BH was spotted with nine other unringed Redshanks. 

Redshank BH - ringing site (Dublin Bay) to re-sighting location 
(Iceland's western fjords). Roughly 1,700 km!

We ringed BH on the 1st February this year at Sandymount Strand in Dublin, and hadn't had any re-sightings until this report from Dyrafjorour in Iceland late last night.

Redshank BH - re-sighting location, Dyrafjorour, Iceland. Olivia Crowe. 

Remember that all re-sightings are hugely valuable us, so please keep them coming in. You can submit your records HERE.

Visible Migration

This week we had a report from a local birder of a colour-ringed Dunlin in South Dublin Bay on April 21st. As part of the Dublin Bay Birds Project, we have ringed a good few (hundreds) Dunlin but we haven’t colour ringed any. We know that the bird was ringed as part of a wader ringing project in North West Africa, at Banc d'Arguin, Mauritania, on January 9th 2013. 

Northward bound - colour ringed Dunlin, 

South Dublin Bay

The Banc d'Arguin stands on the African Atlantic coast, where the ocean and the desert meet. The area comprises shallow coastal areas with extensive mudflats covered by seagrass, small islands, coastal swamps and sand dunes. It is one of the most important areas in the world for migratory waders, holding approximately 2 million birds.

From ringing site to Dublin Bay, but where in between?

We get three difference races of Dunlin in Ireland, two of which, schinzii and artica, winter in west Africa. The schinzii race breeds in small numbers in the northern extremes of Ireland and the UK, as well as in south eastern Greenland, Iceland, the Faroes, Norway and the Baltic. Small numbers of slightly smaller and shorter-billed artica birds move through on passage en route to and from north eastern Greenland each year.    

We are always on the lookout for re-sightings of colour ringed birds, so if you see any, and can read the inscription, combination of colour rings or get a good photo, we would be delighted to have the record. Thanks to all our regular and casual ring readers, we hope you have been enjoying the good weather recently - perfect for ring reading...

Observations can be submitted here.

RW