Dining on Dublin's Docks

Brent Geese have become a very familiar site in Dublin City in recent years often turning up in all sorts of places.Our thanks to Richard Nairn of Natura Environmental Consultants for his insight into the movements of Brent Geese within Dublin Port.

"Brent Geese are now using the inner parts of Dublin Port on a regular basis.  As the winter progresses,  their natural food resources such as eelgrass and green seaweeds become scarcer on the mud and sandflats throughout the bay. The geese seem to have been forced to seek out other feeding areas including golf links, sports pitches and public parks with over a hundred such sites now used around the city.  A recent development has been the tendency of some geese to favour feeding on spilled agricultural products on the quaysides in Dublin Port.   

Feeding flock by the quayside - Richard Nairn

They swim on the River Liffey or in the Alexandra Basin (a deep mooring area for large ships within the port) until any disturbance has passed and then fly up onto the quays where they feed intensively on maize and soya meal among large flocks of pigeons and smaller numbers of gulls.  So far as we are aware this behaviour has not been recorded anywhere else in their range which includes sites in Canada, Iceland and throughout Ireland. I have been monitoring these geese closely over the last few winters and  peaks of up to 450 geese using this source of food have been recorded. 

Brent Geese next to Alexandria Basin - Richard Nairn

 Among them are some colour-ringed geese and the large numbered codes on these rings show that a core group of up to ten individual birds are using the Port on a regular basis, including over several winters.  This suggests that some geese have learned to exploit this food and others then follow them in to share the spoils.

Ringed Brent Goose - Richard Nairn

You can follow the fortunes of the geese on the blog posts of the Irish Brent Goose Research Group at http://irishbrentgoose.blogspot.co.uk/."

Sorry about Knot blogging recently…

This week we received word of two Knot ring recoveries from the BTO. These birds were found dead at two separate locations on islands in the Wadden Sea on the northwest coast of Germany.

Wadden Sea Wikipedia

The Wadden Sea spans from The Netherlands along the coast of Germany and to the western half of the Danish coast. It’s an area well known to ornithologists as many species of waders, geese and ducks winter there, or use it as a re-fuelling or moulting area on their migration. 

The birds were cannon-netted and ringed on 30^th January, 2014 at the Merrion Gate Spit on Sandymount Strand in Dublin Bay. 

Ringing (blue) and recovery (yellow) locations for the two Knots

The first bird (ST40506) was found on 24^th July on the island of Helgoland, a total of 932 km from Dublin Bay. Helgoland is well known for its bird observatory and gives its name to a style of bird trap used to catch birds for ringing. The island is in the middle of a major migratory thoroughfare, so is superbly well placed for studying bird movements. 

The second bird (ST40507) was recovered on 12^th August, 962 km from Dublin, at Sylt Island just off the German coast. This sandy island, connected to the mainland by a causeway, supports thousands of waterbirds each winter. 

Sylt Island, Wadden Sea, Germany Wikipedia

As both birds were described as “long dead” by the finders, it is most likely that these individuals perished on their way to their breeding grounds. They were most likely fuelling up in the Wadden Sea before making a two-step journey to their breeding grounds in Greenland and High Arctic Canada. 

Knot in breeding plumage during spring staging
in northwest Iceland Jan van de Kam

From previous ring recoveries and re-sightings of colour-ringed birds, we know that the Knots in Dublin take alternate routes to their breeding grounds; some stopover in Norway and others stopover in Iceland. We’re delighted to get information on ring recoveries like these as they allow us to shed more light this intriguing situation.

Time for thermals, the Brent Geese are back!

The Brent Geese have arrived, so there is no denying winter is well and truly here. During a count on October 17^th, the Irish Brent Goose Research Group (IBGRG) had a tally of 23,500 at Strangford Lough, which accounts for a substantial proportion of the East Canadian High Arctic population. Most of the birds tend to stage in Strangford before filtering down to the rest of the country, and we tend to get about four of five thousand in Dublin each winter. 

Light-bellied Brent Flock IBGRG

We had about 40,000 birds across the country when they were surveyed last, in 2012, and as this accounts for such a large part of the flyway population, it means they are an important conservation priority for us. All our eggs in one basket and all that…

Sorry about that. Anyway...this year the first arrivals were right on cue, with birds being reported at Kincasslagh, Co. Donegal on September 5^th. The first local record came two days later when, Cian Merne reported two birds at Bull Island on the 7^th.

Dublin’s Brent Geese have adapted to sharing Dublin Bay with the 1.3 million inhabitants of our capital. They are attracted to the expansive intertidal mud flats, where the gorge on their preferred food, Zostera (Eelgrass). Once the Zostera has all been nibbled away, they switch to green algae or else make a move to recreational grasslands around the coast. So, later on in the season, they can be found well inland, on pitches and parks right across the city.

Brent flock feeding in McAuley Park, Dublin IBGRG

Brent Geese have for many years been the subject of an intensive marking study carried out by the IBGRG. In any given group you may spot colour-ringed birds, which are often easily readable with binoculars. All re-sightings should be reported to grahammcelwaine@btinternet.com , but keep a weather eye out for birds with red and blue rings. These birds will have been ringed on their breeding grounds in High Arctic Canada! Some of the research group spent the summer catching geese up there and have some amazing stories to tell.

So, make sure to wrap up, grab your binoculars and get out and have a look around your local patch for all the new winter arrivals.
 

For more info on these little geese check out the excellent IrishBrent Goose Research Group Blog. 

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