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.

Friday, 8 July 2016

Return On Investment

The Dublin Bay Birds Project team took the opportunity to colour-ring some adult common terns on Sandymount Strand, County Dublin last autumn and our efforts have already been rewarded!

We have blogged a number of times about ringing the tern chicks that are born at the Dublin Port breeding colonies. But did you know we have also managed to successfully catch and tag adult birds? Of course we don’t do this at the colonies or even within the nesting season as that could potentially disrupt adult birds incubating and feeding young for example.


Newly fledged Common Tern at Dublin Port
 with metal and colour ring (on left leg) on view
John Fox

Instead we carry out the tagging of adults at Sandymount Strand during the post breeding season (Late august – September). Terns of various species gather and roost here in the early autumn before migrating south for the winter. We know all the birds are not derived from the Dublin colonies from the numbers that accumulate and from the occasional presence of Sandwich Terns (who don’t breed in Dublin) and even Black Terns (which don’t breed in Ireland at all!) You can read all about this pre-migration mass roost at Sandymount Strand here.


A mixed tern flock arrives to roost at Sandymount Strand Dick Coombes

With the ringed chicks it can be three years or more before we would expect to see them on Irish shores once more as it will take this long at least for Common and Arctic Tern chicks to reach sexual maturity and return to the colonies to breed. Adults on the other hand if they survive the winter and migration will be back the following year and we could potentially spot them by re-sighting and reading the ring which in turn may tell us for example, what colony they are breeding and if they successfully rear young.

So we were pleased when our BirdWatch Ireland colleague Brian Burke got in touch from Rockabill Island in early June to ask us if we recognised a few colour ringed Common Terns he had managed to photograph! On inspection of the photos we could confirm our first resightings of the birds since been ringed in Autumn 2015. We also knew instantly that we had ringed them as adults as we place the colour ring on the right leg of adult birds (to avoid confusion as the same colour rings are used on both chicks and adults). 





3 colour-ringed adult Common Terns seen on Rockabill Island,
 PFX, PHL and PKN
Brian Burke


We ringed "PFX" on August 26th, "PHL" on September 7th and "PKN" the very next evening on the 8th, all in 2015. You can see how they are getting on at Rockabill this year here.

We now look forward to the rest of the breeding season to see if any more of our colour ringed birds will show up in Dublin or elsewhere in Europe. The excitement builds as we approach the cusp of the breeding season when we can once more admire the big roosting flocks at Sandymount Strand (and maybe even catch and colour ring a few!).


A short trip for a Common Tern,
Rockabill (north) to Sandymount Strand (south), 

a little over 20 miles apart Google Maps


If you think you have seen one of our colour-ringed terns or any colour ringed bird in Dublin for that matter be sure to let us know at dublinbaybirds@birdwatchireland.ie  

For more info on the colour ringing schemes in operation in Europe see here.