Saturday, 25 June 2016

Rockabill Roseate Tern Count 2016

So we're roundabout the middle of the Tern breeding season at the moment - most either have chicks or have eggs that will very soon be chicks! Last week we carried out a full nest census of the entire island to find out how many pairs of breeding birds we have here on Rockabill. The census took place over two days, checking every nest box, patch of vegetation, and any cracks and crevices that might have Roseate Tern nests, and everywhere in between for Common and Arctic Tern nests!  Thankfuly after a few long and tiring days the news was very positive for our Roseate Terns...
Roseate Terns on Rockabill (picture taken under NPWS license)
Roseate Tern earlier in the season on Rockabill. (picture taken under NPWS license)
We counted 1,556 Roseate Tern nests on Rockabill - that's an increase of over 150 nests from last year. Such a big increase further cements Rockabill's status as the largest Roseate Tern colony in Europe and is down to a lot of hard work from all of the wardens and Birdwatch Ireland staff who have worked here over the years.

Around 700 of those 1556 nests are in nestboxes, again proving their value and importance to the species continued growth. We got around 100 new nestboxes this year thanks to funding from the EU LIFE project, and will hopefully continue to add more and more in the coming years.

Roseate Tern taking a look outside it's nextbox. (picture taken under NPWS license)

Two neighbours squabble atop their nestboxes. (picture taken under NPWS license)

A Roseate Tern sits on it's open nest to incubate two eggs. (picture taken under NPWS license)

This increase also bodes well for the EU LIFE-funded project that will run for the next five years. We'll be sharing our knowledge with wardens from Tern colonies elsewhere in the hope of re-establishing breeding Roseate Terns around Ireland and the UK and further safeguard the future of this elegant seabird! At the moment there are only three colonies in Ireland and the UK. So hopefully some of our Rockabill birds, particularly those from recent years, will stumble upon some suitable sites on their spring migration and decide to nest there in the very near future.

Don't forget, if you want to get an insight into the daily lives of Roseate Terns you can check out the live stream that our friends at RSPB Coquet Island have set-up. It's well worth a look!

Monday, 20 June 2016

Guest Blog: The Dalkey Terns

And now for something completely different... Today we have a blog post from Andrew Butler, the Dalkey Island warden, where we're hoping to establish a colony of Roseate Terns after years of intermittent breeding attempts:

To the north of Dalkey Island lie two small islands, one with some vegetation and one just bare rock. These are Lamb Island and Maidens’ Rock and are home to three species of tern; Common, Arctic and Roseate.

This season for the first time since the late 1990’s we have 32 roseate tern nest boxes on Lamb and 7 on Maidens’, it is also the first time there has been an employed Warden for the islands since the late 1990’s. The new warden and nest boxes are in place thanks to the support of the Roseate Tern EU LIFE Programme, Dun Laoghaire & Rathdown County Council and of course BirdWatch Ireland who run the project.

As well as the nest boxes we have also placed some gravel in the depressions in the rock as nesting substrate, to make the site as attractive as possible to terns looking to breed, especially Roseate Terns.
Loading 'Ken', the ferryman's boat, with nestboxes and gravel amongst other supplies.

We made our first visit Monday 16th May to assess the site and put out some of the gravel then brought out ‘tern meadows’ estate on Tuesday. To our delight we recorded our first egg on the gravel we had placed the day before, an Arctic laid evening 16th or 17th on Maiden’s Rock.

The first egg (Arctic Tern, foreground),  Roseate Tern nest boxes and Steve Newton spreading gravel. for nesting Terns A. Butler, taken under NPWS license.

On 23rd May I made my first dedicated nest search. On Maidens’ Rock I found 5 Nests and 8 Eggs, however one was predated so 4 NESTS and 7 EGGS were recorded (mostly Common).

Since then, I have covered the site weekly to survey the nest status.

Between 4th & 7th June I counted 105 nests between the 3 islands with one nest on Dalkey Island. I hope it’s not doomed as it is surrounded by large gulls, at least they keep the crows away. The nests had a total of 209 eggs.

2 of our first Arctic Tern chicks, one hidden in its neighbour’s nest. A. Butler, taken under NPWS license.

During latest survey between 15th & 18th June I found that 17 nests had been predated, however there were 10 new nests. There was a very significant milestone; we have our first chicks! 23 chicks between the 3 islands, so the lone nest on Dalkey has a chick. We have 169 eggs at the latest count.

Most of the terns currently nesting are Arctics. I hope to have a more accurate split between species as the chicks hatch. This could be a record year in terms of total terns but with no Rosies it’s not the best it could be.

We did have a Roseate visit Thursday 2nd but I didn’t hang around.

View of Tern Meadows, Tuesday evening. Taken under NPWS license.

It’s not all about the birds in Dalkey though. Being beside a big centre of population, people are important in the context of the project and its success. With that in mind and because it’s always nice to introduce people to the wonders of birds I have been running events at Colliemore Harbour and on Dalkey Island. 

Every Tuesday evening and a few we have the Dalkey Tern Watch from the pier, spotting all the birds we can, with most oos and aahs coming from gull and Oystercatcher chicks so far. The walks on the island run after the weekend tern watch, where I tell people about the species breeding on the islands and the importance of giving them space. So far the events have been very successful, so thank you to both those who have just happened upon the events and those dedicated visitors. I’m glad to see a few familiar faces return each week.

Tuesday evening Tern Watch at Colliemore Harbour.

Great Black-backed Gull adult and three chicks seen on the Nature Walk event on Dalkey Island. Picture by A. Butler, taken under NPWS license.

Thursday, 9 June 2016

The importance of Hide and Seek!

It's been a (mostly) sunny and calm couple of weeks on Rockabill and the majority of our Terns are now on nests. We'll be carrying out our whole island nest census very soon, and we should have our first chicks in the coming days!

One of the tasks that's been keeping us busy over the last couple of weeks has been ring reading - that is reading the small metal rings that have been put on the Terns over the years to get a better idea of 'who' exactly we have with us on Rockabill! The rings give us a way of knowing what age our birds are, and if they came from Rockabill originally or from a colony elsewhere - all important information to have for conservation management and future monitoring and planning. Our colleagues at Lady's Island and Coquet Island do the same, giving us a great insight into the Roseate Tern population in this part of the world. The birds don't even know they're wearing the rings - it's like when you forget you're wearing a watch!

Here's David ringing his first Roseate Tern. (Picture taken and ringing carried out under NPWS license)

We do most of our ring-reading from wooden hides placed around the island. This year we added a fourth hide to help us increase the amount of rings we can read and birds we can check in on. Big thanks to Jerry Wray for building what is our most comfortable hide to date! A great spot to sit down with a scope in front of you, listen to a few podcasts on your ipod, and read rings and just generally see what the birds get up to through the day!

Our new ring-reading hide, next to our new terracing and new nestboxes!

We've read the rings of over 600 Roseate Terns this season so far - that's almost a quarter of the Roseates we have here, which isn't bad if we do say so ourselves! It's getting harder to read the rings at the moment as most birds are either sitting tightly on their eggs or gone out fishing, but there'll be another window to read some more at the end of the season.

We ring our Roseates with a 'special' ring on their right leg (e.g. 44R2 above) and a  'normal' BTO ring on the left leg (picture taken under NPWS license)

From last year's ring-reading we know that >98% of our Roseate Terns were born on Rockabill. The Terns are very site-faithful and will prefer to come back to their natal colony in most cases, and return year after year as long as the island is hospitable (i.e. there's suitable habitat and no disturbance!). That other 2% were originally from Ladys Island, though the year before we had a couple of Coquet birds and a French Roseate breeding here too! The majority of breeding Roseate Terns are between 3-10 years old, and within that most are between 3 and 5 years old. We've had one Roseate Tern this year (and two last year) that were 23 years old though! To put that into context, our newest warden David is only 25 years old!

The ages of Roseate Terns recorded on Rockabill last year (2015). 

We've had a few interesting resightings in the last couple of years of Roseate and Common Terns with rings from an African ringing scheme, rather than from the BTO like the ones we use.

This year we have a nesting Roseate Tern that was originally ringed ringed on the coast of Senegal in April 2011, en route to Europe. Since we know where it's nesting now we can keep an eye out for it in future years! In my first year here in 2014 we also had a Common Tern ringed in the same area by the same ringer in April 2013.
Our Roseate Tern was originally ringed 5 years ago as an adult on the coast of Senegal!

And if you think that's impressive, we also have a Common Tern nesting here this year that was born on Rockabill in 1999 (17 years old!) that was subsequently caught in Namibia in February 2007! That's 8,700km away and even further when you keep in mind the Tern would have followed the coast  and sea rather than flying 'straight' there so it's likely to be at least 10,000km with that in mind. A fantastic reminder of the huge journeys our birds undertake every year! It's been seen on Rockabill in 2008, 2009, 2015 and again this year and has more than likely been here every year in between too!

Our Common Tern is 17 years old and was caught in Namibia in 2007 - it's covered a lot of mileage since 1999!

At the start of May a Roseate Tern was seen very far inland over in England, presumably having either been blown off course on migration or perhaps the challenges of long-distance migration had taken their tolls on it and made it disorientated. Unfortunately the bird didn't survive. Since it was in England we might assume it was trying to head to Coquet Island, but the ring on its leg revealed it to be a Rockabill bird, ringed here in 2010. Never assume anything when it comes to wildlife!

Picture of the Rockabill Roseate Tern at Tring Reservoir in England (Picture by Roy Hargeaves  via the Tring Reservoirs HMWT Nature Reserve facebook page)
Over the years we've had reports of Rockabill-ringed Roseate Terns from Iceland, Scotland, various parts of England and Wales, Spain, Denmark, Switzerland, the Azores and even Canada and America! Some of those resightings have been birds visiting other colonies, sometimes to breed, and others are birds either lost or doing some epic wandering!

Some research groups use colour-rings for the same reason we use 'special' rings on our Roseates - easy to see from a distance. We've spotted three Common Terns with yellow rings over the weekend and spent a good 24 hours looking into where they might have come from. They had BTO rings, which meant they were from the British Isles, and since there was two of them they couldn't be from too far away surely? (Don't call me Shirley!) 

'PFX' was seen on Rockabill this week, having originally been ringed in Sandymount. (picture taken under NPWS license)
'PKN' is currently sitting on three eggs out here on Rockabill. (picture taken under NPWS license)

...and 'PHL' is on two eggs out here at the moment! (picture taken under NPWS license)

Well the answer was no, they weren't from too far away at all! They were ringed at Sandymount on the other side of Dublin, where thousands of Terns gather each Autumn before beginning their migration in earnest. With that short distance in mind, the birds likely came from Rockabill in the first place! Not the most exciting of ring recoveries, but still, the more data the better! And I'm sure some yellow-ringed Common Terns will turn up at other colonies in the coming months and years, helping us learn more about the Terns that rely on it as a vital pit-stop before heading to Africa each year. 

We also found a broken blue colour ring earlier in the season , which were used by the Dublin Bay Birds team on their Common Terns last year. I'll let the lads from the Dublin Bay team tell you about that though... (I'm still laughing about it!). Last year we did have a record of a Common Tern ringed in Dublin Port out here, so we do have some evidence of movement between the two sites.

So there you have it - there's loads of information to be gathered from ring-reading at a big seabird colony like this, and lots to be learned! For more information about the value of bird ringing check out the links below!

Tuesday, 7 June 2016

The morning after the day before...

Firstly, we hope everyone enjoyed their Bank Holiday weekend! The weather on Rockabill has been fantastic and our colleagues appear to have enjoyed themselves at  Bloom Festival 2016. And a big welcome to all our of new members too!

Out on Rockabill it's hard to remember what day it is, nevermind whether it's a Bank Holiday or not! We did get a bit of a reminder from some of things we saw around us today though...

The first was a fantastic tall ship from the Dublin Port Riverfest. There was a bit of fog and mist around today so you can imagine our surprise when this appeared just south of the island! Not many people get to look out of their front door and see thousands of Terns and a tall ship slowly sailing by - a nice little reminder of how lucky we are to be doing the work we're doing!

One of the tall ships from Dublin Port takes a spin around Rockabill -an impressive sight!
This Common Tern wasn't as impressed as we were! 

The other thing we saw was completely disheartening - a bunch of balloons on the surface of the sea. These balloons were obviously released on the mainland in celebration of something, but unfortunately no thought was given to the fact that what goes up must come down and those balloons are going to end up somewhere. We've found burst balloons and their ribbons in Black Guillemot and Kittiwake nests on Rockabill, and a mere mention of balloons amongst our seabird colleagues brings up some horrific stories of birds with balloons wrapped around their leg preventing them from feeding, or seabirds, whales, dolphins and turtles mistaking burst balloons for food and eating them and eventually dying as a result. So for the next sunny weekend or bank holiday, if anyone is thinking of having balloons at their event please have a quick word with them and suggest some other way of marking the occasion! 

A bunch of balloons on the sea near Rockabill, presumably released somewhere in Dublin on bank Holiday Monday.
A Fulmar attempting to eat a balloon that was flaoting on the surface of the sea, off the west coast of Ireland (picture by Niall Keogh @nialltkeogh ).
A Guillemot near the Farne Islands, off the east coast of England, with a balloon wrapped around it's leg that prevented it from diving to feed itself. This one was rescued, most aren't so lucky! (picture from David Steel @SteelySeabirder & Em Witcutt @turtlegoblin)

Here's a previous press release on the subject from Birdwatch Ireland, Irish Wildlife Trust, Irish Whale and Dolphin Group and the Irish Seal Sanctuary. By spreading the word to friends and family we can all play a part in making sure this entirely preventable consequences don't continue to happen to our wildlife.

Remember - what goes up must come down!