Sunday, 2 July 2017

Dublin Tern Colonies Bursting With Birds

Tern breeding season is in full swing! We had our first ringing visit of the year to Dublin Port to check up on our summer visitors from Africa. The terns now nest on several structures within the greater Liffey/Port area, such as the disused mooring pontoons near the Poolbeg Chimneys. Most of these support strong numbers of nesting terns, to the extent that some structures near full capacity with adult terns making nests on all available space. As the boat approaches each colony the adults often 'flush' to the skies, screeching and diving. Apart from a small risk of being pecked on the head this is quite a spectacle! It's also a great chance to get a sense of how many terns there are present at the time. From the boat, a count of 290 terns were seen coming off the "ESB Dolphin" - the first established nest site on the Liffey for Common Tern and now protected as part of the many SPA's (Special Area Of Conservation) within Ireland.


The 'ESB Dolphin',
 as seen from the River Liffey Brian Burke 
Adult terns terns flush as the boat approaches the 'CDL Dolphin' Richard Nairn

On a sunny Wednesday afternoon we visited three of the structures in the bay; "Pontoon 1" on the outer Tolka Estuary , "Pontoon 2" and the "CDL Dolphin", both near Poolbeg. Boat transport provided through Dublin Port Co by Jimmy based at Poolbeg Yacht Club, which beats rowing out in the dinghy for sure...thanks Jimmy!


Boat ride with a view of the iconic Poolbeg Brian Burke
Once on the structure the first port-of-call was take a census of all the pulli (young birds that are not yet able to fly) in each section. Then those that were big enough (medium pulli and upwards) were ringed. Common Terns get a metal ring on their right leg and Arctic Terns get a metal ring on their left, so it's easier to differentiate between the two when re-sighted. A "biometrics"  (measurement) are taken for each chick ringed. Wing length is representative of a bird's size so this a good way to keep track of how well they're growing when we visit again.

Pontoon 2. compartments are top real estate for port terns; complete with only the best nesting
gravel, hideaways, chick shelters and not to mention a great view of the port! Brian Burke


Ringing the young terns is a team effort.  Brian Burke
We are sure to spend no more than 30 minutes at each site so as to allow parents to get back to feeding the chicks and all 'round minimise stress on the colony, so we are as efficient as possible when ringing. It's safe to say that it wasn't a bad day's work as c. 150 chicks were ringed and some were even big enough to get colour rings. It's a bonus getting some colour rings on. As demonstrated in the previous blog post, colour rings are so important for re-sighting live birds as they make ring reading so much easier.

"Feed me" - a young Common Tern chick Brian Burke


A young Arctic Tern chick definitely fits in the palm of a hand Brian Burke

A tern nest (using the word "nest" loosely) is just a scrape in the substate and eggs are well camouflaged in the shallow cup, so they can be hard to find but easy to step on. However once you step lightly and know what to look out for the little ones are safe. We are happy with the numbers we've found so far - over 300 nests were found on Pontoon 2 alone. We ringed all suitably robust chicks and will ring the remainder during our next visits.

Although nests are basic, you sometimes see them
decorated with items like this toy plastic fish, which
was probably mistaken for the real thing Brian Burke
A splash of colour. This red/orange colour
 is unusual to see in terns eggs Brian Burke


Creative with crab legs - 
all sorts of materials are used for the nest scrape Brian Burke

So far this season the birds within the wider port colonies are doing a great job and all is going well. In saying that the young terns are sensitive to bad weather conditions and predation events so we'll be eager to get out to the colonies again and keep an eye on their progress. Let's hope those parents keep up the good work! Keep an eye on the blog for updates on how they're doing.

Wednesday, 10 May 2017

2017 Tern Season is Here

The longer the days get the fewer waterbirds we see in Dublin Bay. The Brent Geese are all but gone and we look forward to their return this autumn! But there's little time to reminisce on the winter season past as it's time to gear up for the immanent return of our breeding terns.  

The ESB Dolphin, 
Dublin's largest Common Tern breeding colony Helen Boland

As I write Dublin Bay is seeing more and more terns arrive in from the West-African coast after migrating north to breed on the Irish coastline and at coastal areas throughout Europe. Common Terns Sterna hirundo and Arctic Terns Sterna paradisaea breed within Dublin Bay. Further south Little Terns Sterna Albifrons breed along the North-Wicklow coast and not far off Dublin's coast, north-west Europe's largest Roseate Tern Sterna dougallii breeding colony exists at Rockabill Island. The earliest birds are already prospecting nest sites at these colonies and the first eggs will be laid before long. 

An Adult Common Tern offers his mate a Sand eel Neil Harmey

With eggs expected in late May, our first census visits will take place in the last days of the month. During the census visits, nests (slight depression in the shingle) and eggs are counted and we check for any signs of predation. 

Common Tern eggs in "the nest" Ricky Whelan

Predated Common Tern egg
found during the 2014 breeding season
Niall Tierney

To make things a little tougher for would-be predators, terns have no real nest structure and eggs are cryptically marked so the task of finding them all during census visits can be a little tricky. Once you get your "eye in" the operation runs smoothly! 


A tern nest in an old Dublin Port life buoy Richard Nairn

As the season progresses we return to the colonies to asses what the success rate has been and to colour ring the chicks. The ringing allows us to see if and when birds return to breed at the colony, if they move between colonies as well as where migration might take them each autumn.

Common Tern chicks "fluffies"
 with a bit left to go before fledgling Ricky Whelan
Chicks in the box ready to be ringed Ricky Whelan

Dr Stephen Newton and Helen Boland ringing Common Tern chicks
during the 2014 breeding season
Ricky Whelan


With severe weather, predators and disturbance being the main factors potentially dictating the success of the breeding terns its can be a short but tough few months in Dublin. Despite all the potential risks we know from our long term monitoring that the Dublin Bay colonies have been doing well and the population numbers have remained stable over time. 

Colour-ringed newly fledged Common Tern "PAT" on railings
close to Dublin Port, 2016
John Fox 
This past year our tern colour ringing has paid dividends with multiple reported re-sightings from Namibia on the West-African coast and elsewhere. We want to hear about all re-sightings be it from Courtown, Coruna or Cape Town, so please let us know if you spot any colour ringed terns. Our birds have a metal ring on one leg and a yellow or blue colour-ring on the other. The key info we need is the colour and the alpha-numeric code on inscription on the ring i.e. "PAT". For full details on the scheme and to submit your re-sighting Click Here.

Tern colour ring re-sighting reporting page BirdWatch Ireland

Be sure to visit the blog over the summer months to hear about progress over the breeding season. If you require any more info or just want to get in touch you can email us at: dublinbaybirds@birdwatchireland.ie






Monday, 27 March 2017

New Web App to Record Your Wader Resightings

The Dublin Bay Birds Project Team has developed a Web App to capture your colour ring wader resightings.

With the Dublin Bay Birds Project now well into its fourth year of monitoring we have learned quite a bit about our avian subjects, on what to expect from them and where to expect them to show up! With 525  waders (incl Oystercatchers, Bar-tailed Godwits, Redshanks and Curlew) now colour-ringed as part of this project spring is an exciting time as we await word that they have been spotted somewhere far from Dublin, maybe even somewhere exotic like Iceland!


Oystercatcher "DJ" Orkney, Scotland 2013 Colin Corse



This spring has been no different and already we have international records of seven Oystercatchers who have been making their way northwards to breed in remote parts of Iceland and Scotland for example. Of the 525 waders colour ringed, 380 are Oystercatchers and we have built up a large database of resighting information.

This spring with the help of fellow conservationists in Scotland and Iceland we have had multiple reports of our birds at locations on the Isle of Tiree, the most westerly island of the Inner Hebrides from John Bowler of the RSPB. Johns colleague Morgan Vaughan has sent word of one of our birds "II" from Oransay a small island south of Colonsay in the Scottish Inner Hebrides also! And the record for the furthest north and west has to go to Guðmundur Órn Benediktsson who reported "XT" in Leirhófn, NE Iceland. 


Recent International Oystercatcher resighting records

With spring firmly established on the Dublin coast we see less and less waterbirds each day as they continue to depart for their breeding grounds. Resighting records allow us to track their movements, establish what sites are important stopovers and finally identify where they choose to mate and raise young. All these answers are essential if we have any hope of protecting these important sites and in-turn protect wader species into the future. 


Colour Ring Resightings Web App record viewer


Colour Ring Resightings Web App entry form

We are interested in hearing about all resightings of our project colour ringed birds, be it from Dublin, another Irish county or internationally. If you encounter what you think might be a Dublin Bay Birds Project colour ringed wader, we'd love to hear from you. To make the submitting and viewing of records easy we have developed a web app which you can access here: Report a Colour Ringed Bird . All the information on our colour ring scheme and instructions for the easy to use app are there.


Looking forward to seeing your records and thanks in advance!


Wednesday, 1 March 2017

News from Namibia

Since autumn 2014 we have been colour ringing Common (Sterna hirundo) and Artic Terns (Sterna paradisaea) in Dublin Bay. We colour ring chicks under licence at the breeding colonies within the confines of the Liffey and Tolka Estuary. In addition, we catch and colour ring adult terns on Sandmount Strand where they gather en masse to roost ahead of autumn migration.

"PAT" a colour ringed newly fledged Common Tern
at Dublin Port
John Fox


Last year we received our first foreign (outside Dublin) colour ring resightings. They were made on the Isle of Lewis, Scotland (10/05/2016), Larne Lough, Northern Ireland (10/07/2016) and on Anglesey, Wales (13/072016). Since last season’s autumn migration things had turned quite on the resightings front until two very exciting emails arrived from West Africa in early January!

Two project ringed Common Terns were observed along the Namibian coastline by Mark Boorman a self-confessed “birder” and a veteran tern ringer (with thousands of terns ringed over the years)!

The first bird a Common Tern “PEX” was seen at Mile 4 Salt Works, Swakopmund, Erongo Region, Namibia (-22.597897, 14.519366) and had been ringed on Sandymount Strand, Dublin as a juvenile on 25/08/2015. Mark explained “At the Mile 4 site there are also Sandwich (Sterna sandvicensis), Great Crested (Thalasseus bergii), and sometimes Black Tern (Chlidonias niger) present. A post-breeding flock of Damara Tern (Sternula balaenarum) can be there in late summer. The large flocks of Common Tern are unpredictable as they will utilise any area which is close to their feeding area at that time. The birds roost on the edge of extensive pre-evaporation man-made pans in close proximity to the sea and also on the high beach.”

Mile 4 Salt Works, Namibia Google Maps

The second, again a Common Tern “PTU” was seen further south at Pelican Point (-22.882860, 14.439098). PTU was ringed as a juvenile four days later than PEX again on Sandymount Strand on 28/08/2015. Mark said “At Pelican Point once again the flocks are unpredictable and can gather from place to place. Here they will also be close (within a couple of hundred metres) to the sea. At times these flocks can number in their thousands.”


Pelican Point, Namibia Google Maps

In a straight line both sites are over 5400 miles away from the ringing site in Dublin, a good spin by anyone’s standard. In reality, the birds will have made their way down from Europe across into northern Africa and followed the coastline south, feeding and roosting at various staging areas along the way.

As always we are delighted to get such resightings back to us and records like this really show the value of colour ringing projects. Thanks to Mark for his efforts spotting and reading the rings which is not always an easy task! Soon we might be able to return the favour and find one of his birds in Dublin, we'll keep you posted.


It’s still too early in the year for Irish sightings but if you do encounter colour ringed terns and believe they might be Dublin Bay ringed birds please enter your sighting at the link below. We have created a new online web map for capturing these resightings, check out the details of the Dublin Bay scheme and enter your records here.


Monday, 23 January 2017

Dawn Patrol - Brent Goose Census in Dublin Bay

Scopes, clickers and coffees were essential kit last Friday as a crack  BirdWatch Ireland team of 8 quietly slipped into position ahead of sunrise. The pre-dawn preparations were vital to ensure we got accurate counts of all the Brent Geese that had roosted overnight on the tidal waters of Dublin Bay. From Dun Laoghaire to Sutton, the Tolka Estuary, Liffey outer and all around Bull Island there were counters lying in wait making sure not a single goose went uncounted. 

Ready and waiting at Bull Island South Lagoon Ricky Whelan
 Annually Light Bellied Brent Geese (to give their full title!) populations in Dublin Bay and at other coastal sites are monitored by IWeBS - The Irish Wetland Bird Survey.  Once daylight arrives many will leave the coast in search of grazing opportunities on grasslands such as parks and pitches. It would be an impossible task to try find and count these scattered feeding groups, hence the coordinated dawn count!

Brent Geese flock flying overhead Dick Coombes

On the morning we totaled a combined count of 7064 Brent, making them the most numerous waterbird species in Dublin Bay. This number is higher than what we have seen during IWeBS and Dublin Bay Birds Project Counts. The explanation can probably be put down to the timing of the count and capturing all the geese just after dawn as other counts are often conducted later in day by which time the geese may have already departed for inland feeding sites. More information on species numbers within Dublin Bay can be viewed here on the IWeBS Project Page.

Light Bellied Brent Geese resting at a grassland feeding site Dick Coombes

We were thrilled to see such good numbers of Brent. We had plenty of time to count the flocks as they remained roosting well after it had become bright. At around 0930am flocks of various sizes began to leave the coast and head inland as expected. After a successful mission the team returned to a local cafe to tally counts and more importantly for the second coffee of the day!

The BirdWatch Ireland Count Team having a 
well deserved coffee Ricky Whelan

Wednesday, 21 September 2016

Clouded Vision: This month's top 40


We had a load of graphs in the last blog, which focused on the summer months, but as the year moves on, we should too. There are stacks of data to be written up and reported on this month, and because we’re sitting looking at graphs, trend lines and error bars all day every day, we thought we’d find a different way to represent what’s happening in the Bay this month.

Interpreted as “Word Clouds” are the top forty species that you can expect to see in Dublin Bay this month and next. While the position of the text is random, the size of the font represents the abundance of that species in September, based on our low tide data collected over the last three Septembers. 


The top 40 species recorded in Dublin Bay in low tide surveys in
 September 2013, 2014 and 2015. Font size is proportional to the
 number of each species recorded, but the positioning of the text
 is random.

There are lots of Black-headed Gulls, Oystercatchers, Redshanks and Herring Gulls around this month and good numbers of Black-tailed Godwits and Curlews too. The Brent influx hasn't really got going yet, but they are on their way.



Brent Goose will arrive in numbers over the coming weeks David Dillon 

We won’t get many Whimbrel at this time of the year, as the ones that dropped in to spend May with us on their way to breeding grounds, won’t bother calling in on their way to western Africa, and will just do the journey from Iceland in a oner.

Shoveler, Pintail, Wigeon and Teal are waiting in the wings, but won’t really make their presence known for a while yet. We’ll have to wait until mid to late October for decent numbers of any of these. It’ll be the last we see of the terns for a while too. The odd straggler into October wouldn’t be totally surprising, but the majority will have cleared out by now. 


And here’s a sneak peek of what October is likely to have in store. 

The top 40 species recorded in Dublin Bay in low tide surveys in
 October 2013, 2014 and 2015. Font size is proportional to the
 number of each species recorded, but the positioning of the text
 is random.



Friday, 2 September 2016

Summer holidays in Dublin Bay



We know quite a lot about the waterbirds that spend the winter in Dublin Bay, with decades’ worth of monitoring through I-WeBS (the Irish Wetland Bird Survey) and its predecessors having shaped our knowledge and formed a large database of information that can be drawn on. But year-round counts by the Dublin Bay Birds Project since 2013 have revealed a few surprises for summertime in the bay, showing that significant numbers of waterbirds are present outside of the core monitoring period for I-WeBS.

Black-tailed Godwits staging in Dublin Bay Liam Kane


I-WeBS counts have shown that Dublin Bay regularly hosts 33 waterbird species, and wintering numbers regularly exceed 30,000 waterbirds. Among those wintering are large numbers of ducks, geese, waders and gulls, with Light-bellied Brent Goose, Knot, Black-tailed Godwit and Bar-tailed Godwit occurring at internationally important levels. 

The general pattern is that bird numbers across the bay fall sharply after March, and are at their lowest levels in May and June. And then, from late June onwards, we start to see the numbers rising again, and several thousand birds are added each month, until the annual peak in January. 


Average number of waterbirds and seabirds recorded during monthly 
low tide counts between July 2013 and June 2015. Bars refer to the 
total number of birds recorded. Line refers to the average number 
of species recorded. I-WeBS core season = grey, I-WeBS off-season = green. 


In spring, the majority of our waterbirds head for their breeding grounds, and by the end of March many species have disappeared almost entirely. As the days draw out and the temperatures rise, we see the waterbirds in the bay becoming scarcer by the day. Spring soon gives way to summer: the lifeguards are posted on the beaches; the Little Egrets display their wavy plumes, and the skies are filled with melodious Meadow Pipits and Skylarks, raucous Common and Arctic Terns, and the buzzing chitchat of Swallows and Martins on their high-speed aerial chases. But our year-round surveys have shown that it’s not just terns and songbirds that provide the soundtrack for Dublin Bay’s summer. The mudflats are far from bare and silent - Bull Island, Sandymount Strand and the Tolka Estuary provide a rich species list for any waterbird lover.

Colour-ringed Bar-tailed Godwit "DH" in summer plumage Kim Fischer 


In summer, Brent Geese, Wigeon, Teal, Shoveler and Pintail are absent, as are Red-throated Divers, Red-breasted Mergansers and Great Crested Grebes. And like the waterfowl, Knot and Grey Plover are winter-only inhabitants of Dublin Bay, with the vast majority of them recorded between September and March. 

But this isn’t the case for all waders and the bay is particularly important for some species during the summer months. Whimbrel, a passage migrant in Ireland, is practically absent from the Dublin Bay I-WeBS dataset, as it only appears in the I-WeBS off-season. Highest numbers occur in May, when birds are moving northwards to breed, and in July, when they are en route to their wintering grounds. 

Black-tailed Godwits occur in the bay in internationally important numbers through the I-WeBS season, but April and August see significant numbers too. The spring influx starts in March and the birds are still present in April, before disappearing off to Iceland to breed. By July there are birds back in Dublin, and by August their numbers have risen to exceed the international threshold once again.  

Oystercatchers, too, are a Dublin Bay staple, being present in each month of the year. Numbers during the winter are much higher, but the threshold for national importance is exceeded in four out of the five I-WeBS off-season months, showing how important the site is for them during the summer.   

Average number of birds counted per month 
on monthly low tide counts between 
July 2013 and June 2015. The orange lines refer to 
the 1% threshold for national importance, and the grey 
line refers to the 1% threshold for international 
importance. Note that Whimbrel numbers in Ireland
 do not reach the international threshold and no 
thresholds of national importance are available. 

So, through this project, we have been able to appreciate the year-round importance of Dublin Bay for some waterbirds, and have been able to see just how important it is as a staging site in spring and autumn. Although the official I-WeBS period is September to March, the I-WeBS Office will very happily accept any counts taken in the off-season, as they may shed new light on the importance of other sites during this period.