A Moving Story

Join us for a day of ring-reading and learning about migration on Saturday 17th October. 

Since the first colour ring was fitted as part of the Dublin Bay Birds Project on the 19th October, 2012, we’ve been doggedly trying to get as many re-sightings of these birds as possible. Nearly three years later, we’ve fitted many more rings and are still on the hunt for these colourful individuals. We’re learning lots about these birds, both locally and internationally, but equally, new questions are being raised.

To date, 396 waders have been colour-ringed with a breakdown of 262 Oystercatchers, 99 Bar-tailed Godwits and 35 Redshanks. Colour-ringing is a fantastic tool for us, as it allows us to generate lots of data on individual birds without the need to recapture them – we can easily identify each bird according to the inscription on its brightly coloured rings.

Colour-ringed Redshank Niall Tierney

There is no question that reading the rings (and submitted them!) is time well spent, and it is very enjoyable too. Time spent in the wilds of the Dublin coast, with the bustle of the city behind you is surely always time well spent. The thrill of successfully “getting” the rings starts to become addictive over time. You start to become familiar with regular individuals at their haunts, and look forward to their return from breeding areas in Scotland and Iceland. 

Colour-ringed Oystercatchers on Sandymount Strand John Fox

Come spring, most of our colour-ringed birds will leave Dublin and indeed the country altogether, and this is when it really gets exciting. We open our emails each morning with huge anticipation, hoping for messages with foreign names from far-flung places bringing news of “our” birds. We have had re-sightings from Scotland, Iceland, Norway and the Faroe Islands so far.  It’s always brilliant to get a foreign re-sighting, but it’s even better to connect with that bird back on Irish soil (or sand!) in the autumn.

Oystercatcher re-sightings outside Dublin. Blue marker: Ringing site (Merrion Gates, Sandymount Strand), red markers: re-sighting locations of Dublin-ringed birds, green markers: original ringing locations for ‘FH’ and ‘HD’, which were recaptured in Dublin in February 2013 and colour-ringed.

We would love to see more birders and nature enthusiasts out keeping an eye on our birds and piecing their stories together. Every single re-sighting we receive adds to our ever-growing dataset, tells us more about how the birds are using their winter home and informs us on how we can conserve it.

Reading colour-rings on Sandymount Strand Jen Lynch

If you are interested in trying out some ring-reading and hearing more about the Dublin Bay Birds Project, why not come along to our ring reading day at Bull Island on Saturday, October 17^th? On the day we will be on hand, with experienced ring-readers, to introduce you to ring-reading, and we will take to the coast to scrutinise the local flocks for ringed birds. It’s a fantastic time of year to get out and see the huge numbers of waterbirds that use Dublin Bay.

What: Dublin Bay Ring Reading Day

Where: meeting at Bull Island Visitor Centre

When: Saturday October 17^th @10am

What to bring: Binoculars and scope (if you have some), Wellies, suitable clothing and some lunch.

Beach Party!

Autumn is upon us, but you can still catch the last beach party of the year.

Each year we observe the coming and going of autumn migration. Amid the current migrants passing along the east coast are good numbers of sea terns. These terns gather to roost as dusk approaches on the Dublin coast, and Sandymount Strand is a favorite spot, attracting thousands of birds each evening. This gathering starts when the breeding season is over, and the spectacle of thousands of roosting terns can be seen from mid-August until mid-September. These flocks made up of a species mix, gathered together as they share a migration route to Africa and beyond. Numbers will have nose-dived by mid-September, and you’ll be lucky to see a tern in Dublin after that.

Sandymount Strand awaits the arrival
of the terns Jen Lynch

So far this year we observed a peak of 4,200 terns. The group is made up of a number of different species, the vast majority of which are Common Terns. The remainder is made up of Arctic and Roseate Terns, and, to a much lesser extent, Sandwich Terns.

Sandwich Tern Fishing Dick Coombes

The presence of Rockabill-ringed Roseate Terns, as well as Dublin Port-ringed Arctic and Common Terns, proves the local provenience of individuals within the group. But the Sandwich Terns show that it’s not just locally breeding terns that join the roost. The nearest Sandwich Tern colonies are Wexford and Down, which tells us that birds are coming to Dublin to the roost from further afield. More interestingly, we see Black Terns with these birds on an almost annual basis. Black Terns belong to the "marsh terns" group, as opposed to the “sea terns” mentioned above. They breed on the freshwater marshlands of Holland, Poland and further east.

The fact that these birds are attracted from so far afield shows how important Dublin Bay and Sandymount Strand is for these birds, as they undertake their epic migrations to the west African coast (and far beyond for the Arctics). A record number of 51 Black Terns was observed by local birders in the flock at Sandymount on the 23rd of August and, across the Liffey, on Dollymount Strand, a White-winged Black Tern was seen. 

Ringed Roseate Tern Dick Coombes

It’s wonderful to be able to watch this migration in action, and great that’s this spectacle happens right on Dublin’s doorstep! It is a very short-lived event, though, and can only be seen between mid-August and mid-September. So grab your jacket and binoculars and get over to the coast before these graceful little creatures leave our shores for another year.

BirdWatch Ireland members enjoying the spectacle Jen Lynch

Returning Waders Add a Splash of Colour to Dublin Bay

After the summer lull, waders are now flocking back to our shores. It's that time of year, and they are on the move from their Arctic breeding grounds. We are in the early phase of autumn migration and many species can still be seen in their charismatic breeding plumage. 

Birds change their feathers every year: good quality feathers are vital for efficient flight and for insulation, but there is a need for a wardrobe chance ahead of the breeding season. A striking, colourful ensemble is essential to attract a mate and to show off to rivals. Many waders migrate northwards before moulting, so we rarely get to see them in their Sunday best. August presents us with the rare opportunity to see returning birds still retaining their breeding finery, before the post-breeding moult leaves them dull and drab for the winter months. 

Winter plumaged Bar-tailed Godwit  John Fox

There are some handsome examples to be seen in Dublin this month, so make sure to take the time to get out and have a look. Among them, Bar-tailed Godwits have returned from northern Scandinavia and Siberia, and feeding parties may be observed probing for buried morcels the tide line. Scattered around the flock are birds with rich brick-red underparts, which extending unbroken from head to tail. This contrasts with the dark wings with golden specs admixed with the grey, black and brown feathers. The Tolka Estuary is a good place to see these flocks on a rising tide. 

Dunlin can easily be identified at the moment by their distinctive black bellies, which will turn pale as the weeks wear on. Now, they have rufous and black wings, white flanks and a black belly just like they were swimming in black ink. They will become brown-grey above and white below soon, and will blend well with Sanderling and Ringed Plover later in the season. You will find Dunlin on Dollymount Strand and south of the Bull Island causeway at this time of year. 

Dunlin in Summer plimage  Clive Timmons

It’s a good time to see other species on their way through, following the Dublin coast on their way to Africa. Whimbrel can be seen and heard now, but can be difficult to distinguish from the slightly larger, longer-billed Curlew. Their call, on the other hand, is unique. Try learning the call before going looking for them; it's described as a loud, rippling whistle “pü pü pü pü pü pü pü”. Greenshank are also great to see at this time of the year.  Like a Redshank’s paler and lankier older brother, they have very white under parts contrasting with the dark wings. You can see them loosely associating with feeding flocks of Redshanks, but their longer legs allow they to exploit deeper pools. 

Whimbrel  John Fox

So get out there and see what returning waders you can spot this month, as always keep an eye out for colour ringed birds as we are always looking for re-sightings of our project ringed birds.

A Fly on the Wall Look at the Dublin Port Tern Colony

Due to tern chick predation by a mystery predator, we deployed a motion-triggered “trail camera” in an effort to identify the visiting culprit. 

When we retrieved the memory card some days later, we were disappointed not to have identified the predator, but we did capture an intriguing insight into the activities and routines of the terns when completely undisturbed on the colony. 

In the three days, the camera was triggered 2,088 times, and after meticulously scrutinising each photo, we discovered that the platform is not just home to terns at this time of the year. 

Nocturnal squatters started to appear around 8 pm each evening and stayed overnight, roosting on the boundary planks and within the nesting compartments until shortly after 5 am each morning. Although the camera was directed into just one nesting compartment, it was clear from the sequence of photos that Starlings use the structure as a night time communal roost with very little, if any, reaction from the nesting terns.

Adult and juvenile Starlings get some sleep among the nesting terns
Ricky Whelan

The early bird gets the....sand eel (bird centre foreground) Ricky Whelan

We also managed to make some observations on the hours that the terns keep. They became active between 4 and 4:30 am each day, and the earliest food delivery occurred at 5:19 am. As expected, the adults spent their day diligently coming and going with food, resting and occasionally brooding young chicks and eggs. Sporadically, the terns do what’s known as a “dread.” Dreading is when the entire tern colony suddenly and silently (unusually for terns!) takes to the air and vacates the nesting area and performs a few looping laps of the nesting site, before returning to business as usual. Dreads are pretty much over as soon as they start, and in general, last less than about 10 seconds. This behaviour is associated with the terns being startled by an avian predator, but often occurs with no apparent stimulus.

Dreading adult terns leave the nesting colony briefly Ricky Whelan

Peace at last. Common Tern chicks and adults roosting for the night

 with Starlings tucked in along the left hand edge Ricky Whelan

As the light fades, the frequency of prey deliveries declines and everyone is settled down for the night by about 10 pm. 

So, while we didn't manage to get confirmation on the mystery predator, (which we suspect is Mink or Rat), we did get some interesting insights into the tern activity on the platforms when they are left to their own devices. The effect that this predation has had on the overall colony success this season has yet to be measured, but will be quantified by the end of the season.

Tern Talk

School’s out, but we’ve still got plenty of work to do. As the seasons pass, we see huge differences in the composition of the birdlife in Dublin Bay. And new arrivals mean different survey types to adequately determine how they are all doing. Tern time is always a very busy time for us… which may explain the lack of blog posts recently! 

Many of the waders and wildfowl are now long gone, with only a fraction of their winter numbers remaining. Last February, we had a total of 38,854 waterbirds in Dublin Bay during a low tide survey. The corresponding number in June was just 3,566. But that doesn’t mean that Dublin Bay is not important for waterbirds in the summer -far from it, in fact, but that’s for another post!

But it’s tern time for us now, and it will be until around about the time that the kids go back to school and the terns go back to Africa (and beyond). So, right now, we’re flat out doing nest censuses, ringing and colour-ringing chicks and assessing foraging locations within Dublin Bay. And before too long, we’ll be assessing the numbers of post-breeding terns roosting on Sandymount Stand in late August and early September. At which point, the waders will be flying in and the wildfowl won’t be too far behind them. So, it’s always worth taking the time to enjoy the breeding season before it passes...

Common Terns  Niall Tierney

Arctic Tern nest at the foot of a mooring bollard Niall Tierney

Arctic Tern nest Niall Tierney

Arctic Tern nest Niall Tierney

Arctic Tern nest Niall Tierney

Erythristic Arctic Tern eggs Niall Tierney

Common Tern nest Niall Tierney

Common Tern nest Niall Tierney 

Newly hatched Common Tern Niall Tierney

Common Tern chick Niall Tierney

Common Tern chicks Niall Tierney

All photos taken under NPWS licence. 

Spring Break

Bird life in Dublin Bay certainly has changed to reflect the coming and passing of spring. As we discussed in our two preceding blogs many of our familiar species have headed north in an effort to mate and hopefully successfully breed at their respective breeding grounds. For the most part it's business as usual for the Dublin Bay Birds Project Team. We continue our monthly suite of waterbird counts and have seen increasing numbers of terns return to the bay in anticipation of their breeding season ahead. A new tern-breeding raft has been installed north of the Great South Wall in the past month and we will keep a close eye on the "take up" of breeding pairs on the raft as the season develops.

Last week our own Niall Tierney took the opportunity to visit Iceland for a short holiday. Showing true commitment to the project he has spent much of his time in Iceland combing the coastlines' fjords and bays for project-ringed birds. Lo and behold he has connected with one of our birds previously caught and ringed at Sandymount Strand as part of our project work last February.

Oystercatcher "FL" foraging last week on the Icelandic coast - Niall Tierney

Word has reached us of two sightings the Oystercatcher "FL"(the birds individual code) on the 6th and 16th of May at Hvalfjordur which is located on the south western side of the Icelandic coast. Niall reports "FL" has been with a non-breeding flock of c140 oystercatchers frequenting the area. It must have been a great experience for Niall to have caught and possibly even personally ringed FL in Dublin last February (HEREs the blog from that catch day) and then see it in Iceland where it has returned in an attempt to find a mate and raise young this spring. We look forward to hear more details from Niall in the coming days. 

Oystercatcher "FL" re-sighted at Hvalfjordur Iceland

Standby for more re-sighting stories as the season develops and for news on the breeding tern season ahead.

BirdWatch Ireland is currently running a campaign (along side other EU Birdlife partners) in an effort to stop the European Commission from reopening and making negative changes to two EU Directives. The strength of the EU Habitats Directive and The Birds Directive is under threat. These laws are incorporated into Irish law and are the vital in protecting the habitats and species of Dublin Bay and throughout the rest of Ireland and Europe. Please follow the link HERE and take a few minutes to help this campaign.

April Fowl

As spring is (almost) turning to summer, there is also a transformation in the bird life of Dublin Bay. Having spent the winter taking bi-monthly counts of the birds at Bull Island, I have watched the birds in the lagoon shift with the seasons. Not only are new species arriving and others heading off around the world, but the appearance and behaviour of certain species is adjusting to the warmer season.

The difference most apparent to me were birds coming into their colourful summer plumage, which is generally much more striking and attractive than winter plumage (and makes identifying species at distance a much faster task!). Many of the Black-tailed Godwit have already traded their plain brown winter plumage for vibrant rufous-orange on the neck and black barring on the breast. Similarly, Dunlin become a rich chestnut with a prominent black belly patch, rather than their wintertime grey-brown. The Black-headed Gulls finally live up to their name and develop a striking chocolate-brown head for the breeding season. This emergence of birds in full breeding plumage signals the birdy courtship season is in full swing and summer is truly on its way!

Black-tailed Godwit in breeding plumage (Andrew Kelly)

 Black-headed Gull living up to its name (Oran O’Sullivan)

Dunlin in summer colours (Ken Kinsella)

The change is not only in appearance but also, of course, in behaviour. As their migration departure is approaching fast, the Brent Geese at Bull Island are frantically building stores to see them through the journey. Since they have spent the winter gorging all the eelgrass and algae in sight, by spring Brent Geese must look for something new to devour. In the last month I have observed more geese feeding in the grass around the lagoon instead of the intertidal zone within the lagoon. Early in winter, the geese feed on eelgrass and algae at low tide, but when all of it has been eaten away, they begin to graze grassland. This reflects how the change in vegetation through the seasons influences the bird life, as some sources become depleted and others are made available.

Perhaps the most significant change through the seasons is inward and outward migration to and from Dublin Bay. By late April, most of the over-wintering species have left Ireland and summer species are arriving. I have noticed a reduction in wintering species’ population numbers at Bull Island during April counts, as migration to their summer grounds gets underway. Smaller numbers of Sanderling, Knot and Turnstone meander around the lagoon, while Wigeon and Teal in particular have disappeared off my radar. But the upside to the absence of these birds are the arrival of summertime species to Bull Island. I spotted my first two Sandwich Terns of the season pottering around the lagoon just last week - something that screams “summer is here!!” in my face.       

While my bird counts at Bull Island are finished for this winter season, the spring transformation is set to continue. More summer species, such as the remaining Terns, will arrive, and those Brent Geese inhaling the grass will abscond to Canada. Hopefully this summer will be a kind one to our breeding birds and next winter’s monthly counts will show positive results!

Susan Doyle