Thursday, 30 April 2015

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

Friday, 3 April 2015

March: In like a lion, out like a lamb…or did we get that backwards?

We have seen the end of March, and Spring is in full swing throughout Dublin Bay. Our schedule of bi-monthly surveys have allowed us to see all the changes that happen across the month, and at this time of year, Dublin Bay becomes an airport terminal, with passengers arriving a departing from far and wide.

In the past few weeks, bird numbers throughout the bay have been steadily decreasing, as waterfowl, waders and gulls take flights to their breeding grounds. The Teal will end up in Iceland, northern Europe and Russia; the Knot will head for Greenland and Canada, after staging in Iceland or Norway; and the Black-headed Gulls will spread out again right across northern Europe.

On the ground, the sound of wee-oo-ing Wigeon is replaced by the coor-eee of Whimbrel passing through on their way northwards having wintered on the West African coast. On Bull Island, singing Skylarks nearly drown everything else out, but what a welcome sound it is. And there has been a Meadow Pipit singing his heart out over the spit at Merrion gates too.

These days, the project team open our inboxes each morning in anticipation of getting emails from northern climes, bringing news of Dublin-ringed Oystercatchers, Redshanks and Bar-tailed Godwits en route to, or on, their breeding grounds. Last week, we heard from Ian Durston from Nairn in Scotland who has one of our birds breeding in the field next to his house. XI has taken up residence in a stubble field in Cawdor, Nairn and seems to have paired up, so it may not be too long before he hears the pitter-patter of tiny …cockle-stabbers.

XI and mate in Nairn, Scotland Ian Durston

The Brent Geese are preparing for their imminent departure, before re-fuelling in Iceland, crossing the Greenland Icecap and finally arriving in Artic Canada. Soon there won't be sight nor sound of them until they return in September. But now we're on standby for the arrival of the breeding terns. Sandwich Terns tend to take an earlier flight than the rest, and handfuls have been seen already, but it’s the Common and Arctic Terns that we’re waiting for. Their harsh and rasping screechy calls will herald the onset of summer fieldwork, and trips to the Port to ring the chicks and monitor the breeding success of the colony. 

So, there's plenty to see in Dublin Bay - it's an ideal time of year to get out and see migration for yourself, to observe the comings and goings of spring

Wednesday, 1 April 2015

Ecologists strike it lucky!

BirdWatch Ireland’s waterbird ecologists working on the Dublin Bay Birds project spend a lot of time on Sandymount Strand and have struck it lucky with a remarkable discovery.

A sea-front curtain-twitcher remarked:

“They seem to be here all the time! I’ve seen them here at all hours of the day and night – with their telescopes watching the birds, catching them and marking them with plastic leg rings, or even tracking the Oystercatchers with radio-antennas, so it’s little wonder that they were the ones to find the gold.”

“When I saw the low rainbows, I started to think about their significance,” said one of the project team, who also has a keen interest in Irish folklore. “My grandfather comes from Slieve-an-ore [Gold Mountain], near Feakle in Clare. He has seen the low rainbows there too, and told me what they mean. Tales of leprechauns and pots of gold are not just bedtime stories, despite what people may think.”

Squally showers on Sandymount Strand Niall Tierney
The ecologist continued:
We managed to get some spades and sieves from colleagues in nearby UCD and got straight to work. It’s not rocket-science – it’s simply a matter of scouring the sandflats looking for signs of mineralisation, and then getting busy with our spades and sieves. The gold pellets are pretty obvious, once you get your eye in.”

Sifting through the sediment Niall Tierney

Others have suggested that the gold may originate from one of the many shipwrecks in Dublin Bay and that it may just be washing up now, after the storm force gales of Monday night. The steamship RMS Leinster, which was torpedoed by a German U-boat UB-123 on the 10th October, 1918, is emerging as the prime candidate, as military historians have long speculated on the likelihood that she was carrying a significant cargo of gold.

Whatever the source of the gold, it’s expected that, much like the infamous 19th century gold rushes, people will flock to the Dublin coast aspiring to make their fortunes.

Susan and Helen make their way back with their loot Niall Tierney
BirdWatch Ireland has remained tight-lipped about how it will spend its windfall. However, a source close to Ireland’s largest nature conservation organisation suggested that the money will either be spent on an ambitious plan to create the world‘s largest aviary by roofing Co. Wicklow, or on a Passenger Pigeon re-introduction project, which aims to solve the world’s hunger crisis.