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

Survey "work"

While you were all slaving away in your offices yesterday, the Dublin Bay Birds team was out surveying in Dublin bay, where the sun was splitting the stones. There is no better way to count waders, than with Skylarks providing the tunes and with Swallows acrobatically chasing overhead. As I stood on the causeway in my tee shirt with my ice-cream, I wondered if I should have brought sun cream. Then I pinched myself, and started my work…

There have been big changes around the bay since last month’s count. The Wigeon, Teal, Shoveler and Pintail have all gone, and the Brent Geese are fervently fuelling up for their imminent departure. The Oystercatcher numbers have more than halved since last month, and the Bar-tailed Godwits have all but disappeared. There are still plenty of Black-tailed Godwits around, but now, sporting their tomato soup-coloured glad rags, they really stand out on the mudflats. There are also lots of Redshanks around now too, but these ones are likely to be birds that have wintered further to the south, who are on their way northwards.

Black-tailed Godwit in breeding plumage Shay Connolly

I stopped in at Merrion Gates to read some Oystercatcher rings on my way to back to the office, and was delighted to hear the grating kerrick calls of Sandwich Terns over the strand. These harsh calls foretell the arrival of their Common and Arctic cousins, who will be arriving back to their breeding platforms in Dublin port in the coming weeks.  

Sandwich Terns in breeding plumage Shay Connolly

Just two of our radio-tagged birds, Redshanks AN and AP, remain from the eleven birds we tagged in January. We got some great data from them before they left, and now the job is to get this data out of notebooks, mapped and moulded into something useful!  

See you in Iceland!

I got an email this morning from Jim Wilson, who coordinates the fantastic International Schools Godwit Project. Jim had been contacted about colour-ringed Oystercatcher “CU”, which had just been seen in Stokkseyri in southern Iceland! This is great news as it is the first re-sighting of our Dublin-ringed birds in Iceland!

Wintering and breeding sites for Oystercatcher CU.
Blue marker: ringing and wintering site.
Red marker: breeding location.

CU is reported to be on its breeding territory with its mate.  It had been re-sighted 5 times on Sandymount Strand since it was ringed there on the 26^th February, 2013, with the most recent re-sighting being on the 4^th March this year.

Oystercatcher CU on breeding territory in 
Stokkseyri, Iceland.  Tómas Grétar Gunnarsson 

While we don’t know what age CU is, we know that it hatched at least four years ago. CU had a bill length of 78 mm when we ringed it, which suggests that it tends to prise open cockle and mussel shells, rather than smashing them open like some of its shorter billed buddies.