Saturday, 6 September 2014

Rockabill 2014 - That's all folks!

Apologies for the lack of updates - the end of the season was hectic, packing away nestboxes and ringing the last few chicks, followed by some packing and cleaning and our return to the mainland on Friday the 8th of August! We have to give big thanks to Aine (former Rockabill Warden!) and Kristina (Kittiwake fanatic) for their help over the last week - without them we'd probably still be out there scrubbing nestboxes and looking for clothes pegs.....  We allowed ourselves a week's rest to try and re-integrate ourselves into society: meeting people, seeing stuff like cars and crows the first time in months, eating proper food, the luxury of electricity, and the unfamiliar feeling of walking around with little or no risk of being attacked by Common Terns!!
Since then we've been reflecting on the season that was, and crunching the numbers of the huge amount of data we gathered to see what kind of season it was compared to previous years - here's a species-by-species summary:

Black Guillemots:

Black Guillemot, starting to come into winter plumage. (Picture taken under NPWS license)

Black Guillemot (picture taken under NPWS license)

Morning counts early in the season confirmed what we already knew - the severe and prolonged storms last winter have had a big impact on our Auk species. Large numbers of Guillemots and Puffins washed up on beaches and shorelines around the country, including Black Guillemots that were ringed on Rockabill as chicks in previous years. So it was of little surprise that the breeding population was a decline of over 40%  from last year, down to 54 pairs. But it's not all bad news. Clutch sizes this year were only slightly lower than previous years, and productivity (the number of chicks fledged per nest) wasn't too bad either - not the best in recent years, but still good. Fingers crossed for some calmer weather over the next few winters and hopefully we'll see some steady recovery of the Black Guillemot population in the coming years.


Kittiwake adult and chick. (Picture taken under NPWS license)

The Rockabill Kittiwake population underwent a sudden and unexpected decline last year, but thankfully numbers bounced back a lot of the way this year to over 150 pairs. In contrast to the BG's, clutch size for Kittiwakes was better than last year, with several 3-egg clutches. Productivity too was healthy compared to previous years, though we did lose two chicks to a visiting Peregrine Falcon late in the season - possibly the same bird that depredated an adult or two at the start of the season! Of course the Peregrine Falcon is a fantastic bird, and this kind of predation is perfectly natural and won't have a major long-term affect on the Rockabill Kittiwakes. Nothing to worry about! And if I was a Peregrine and had the choice between a Tern chick or a Kittiwake chick, I know which I'd be picking, though I am a little bit biased! So in summary - Kittiwakes - not a bad year, and certainly an improvement from 2013!

 Roseate Terns:

A Roseate Tern midway through the season (see the red on its beak!) (Picture taken under NPWS license)

You're probably sick of hearing it, but I think it bears repeating - Rockabill Island off the coast of north Co. Dublin has the largest single colony of Roseate Terns in Europe! The biggest in Europe! Over 40% of the European population if you count the Azores, and over 80% of the population of Ireland, the UK and mainland Europe. That's pretty good going for an island with a smaller area than a football pitch that's only a stones throw* from our capital city! You might need a medieval catapult to throw the stone.....and we don't recommend you try....but you get my point! Rockabill is pretty important for Roseate Terns in this part of the world, and they're the reason we were out there all summer. So it was a good year for Kittiwakes on Rockabill, not a good year for Black Guillemots - how about the priority species - the Roseate Tern?.................

Roseate Tern using one of the 600 or so nestboxes we put out for them. (Picture taken under NPWS license)

Well, it started off good anyway! We had almost 1,250 pairs of Roseate Terns breeding during the nest census in June - around 20 more than last year, and a new Rockabill record. Nest box usage was as high as ever, and plenty more pairs made use of the shelter of rocks, vegetation and even nesting between the nestboxes themselves! Following that, clutch sizes and hatching rates were in line with previous years. So far so good.....
Unfortunately, things didn't go very well from there. Despite the good weather productivity was quite very low this year  with less than one chick fledging per nest. Many Roseates had 2 chicks, but the second chick died in over 85% of nests, and in some cases the first chick died too. By the end of the season we were struggling to find nests with 2 chicks. Pairs that laid in nestboxes did noticeably better than those with open nests, as is usually the case, highlighting the importance of putting them out!
From weighing the chicks we know that growth rates were very low compared to previous years. Worryingly, as the season went on we were finding large numbers of Snake Pipefish around the island. Pipefish have little-or-no food value to growing chicks, and elsewhere they've been associated with a lack of suitable food when found at seabird colonies, and the spread of certain species into Northern Europe has been linked to climate change. So it looks like our Roseate Terns couldn't find enough food of good quality to feed their chicks. This hasn't been a problem in the past, and it could just be a one-off this year -  we will have to see in the coming years how the Rockabill Terns fare, and what this can tell us about what is going on below the water surface in the Irish Sea.

Common Terns:

Common Tern (Picture taken under NPWS license)
Common Tern fledgling begging for food (Picture taken under NPWS license)

The species we developed a real love/hate relationship with this summer! We loved to watch them from a distance, their behaviours and interactions with each other and the way they'll nest pretty much anywhere, but what we didn't like were the constant, persistent attacks - heads, arms and fingers were cut, coats and pants were ruined, and we had a ringing in our ears for days after leaving the island!

Never a moments peace when the Common Terns are around! (picture taken under NPWS license)
So Common Terns have a lot of differences with Roseate Terns, but a lot of basic similarities too - and with that in mind the results of their season was largely the same as for the Roseates. We had very high numbers in the nest census, over 2,150 pairs breeding, and clutch sizes and hatching were all looking good. And it was all downhill from there! Common Terns often have 3 chicks, but we know of no clutch of 3 where all chicks survived to fledge. Indeed in the vast majority of 2 and 3 chick nests it was only the first chick that hatched that went on to fledge - usually you'd expect a decent percentage of 2nd chicks, and the odd 3rd chick to survive too. In the end a significantly lower number of chicks left Rockabill this year compared to previous years. As above, this could be a sign of greater changes in the Irish Sea - only time will tell.

Arctic Terns:

Nearly forgot about these guys! Unfortunately all of the Arctic Tern nests on both the Rock and Bill were predated by Herring and Great Black-Backed Gulls this year......making this a pretty short paragraph...........

Other Stuff:

Jellyfish! Lots of them! We recorded four species around the island this year, most of which were Common/Moon Jellyfish, with a decent amount of Lion's Mane Jellyfish too. Here's an article by Birdwatch Ireland's Melanie Gomes about Jellyfish around Ireland and what their large numbers might mean 

Lions Mane Jellyfish - and there was plenty more where that came from!
We also had a number of seals keeping us company!

Our bird species list finished on 40 species - with late additions of Redshank and Whimbrel passing through, and Purple Sandpipers - some of which would have been moving through, and others of whom will spend the winter on Rockabill and at places like the piers in Dun Laoghaire - lovely birds, keep your eye out for them!

Turnstones, ever-present but not breeding on Rockabill.

Go see some Terns before they leave for Africa! As the breeding season has all but drawn to a close, thousands numbers of Terns from Rockabill and elsewherein Ireland/Europe, of a number of species, will be spending their evenings at Sandymount in Dublin. Check out the Dublin Bay Birds Blog for more details, andmake sure to take a trip down to see a fantastic wildlife spectacle - and keepan eye out for the lads while you're down there! 

The 'Irish Sea Symposium' is coming up later in September (19th,20th) and includes a talk from Richard Nairn on 'Nature of the Irish Sea Coast'. Richard was director of the Irish Wildbird Conservancy (now Birdwatch Ireland) when wardening was established on Rockabill in 1989, and it promises to be an interesting lecture. See for more details.

And lastly, one of the big things that affects our seas - the fish, the seabirds, and the value of the seas to our economy in the future - is the Common Fisheries Policy and how we implement it. If you click this link it'll direct you to a template letter you can send to your local TD to let them know you want to see this legislation implemented wisely and based on sound scientific and economic evidence - it only takes a second to do and is very worthwhile!

So the last thing is to say thanks! To the NPWS and Commission of Irish Lights for financing and facilitating the work on Rockabill. The longer the project goes on the more we learn and the more important data we can gather not only on this internationally important colony, but on the health and stability of this part of the Irish Sea.
Heading to Rockabill for the first time with the guys from Skerries Seatours!

We'd also like to give a huge thanks to Eoin and Gerry from Skerries Seatours for dropping us out, bringing us home and delivering us burgers, pizzas and volunteers throughout the season. Give their page a like on facebook and keep them in mind if you want to do something different and memorable with a summers afternoon!

We'd like to thanks everyone at Birdwatch Ireland, especially to Dr. Steve Newton for everything throughout the season - we learned a lot of important skills and information that we'll carry on with us for the rest of our careers, and we enjoyed (almost) every minute of it! Also if he didn't bring us out food on his visits we wouldn't have survived past June, so that was good too.........

Thanks Steve! (Rockabill hide-and-seek champion 25 years running...)

We'd also like to thank all of the volunteers and guests over the summer for their help and company, and to the various media people we talked to over the course of the whole project. And lastly thanks to everyone who has read and enjoyed the blog - we've had thousands of views over the summer from all over the world and we hope you've enjoyed hearing about one of the jewels in Ireland's wildlife crown!

We had a very enjoyable summer and we're already looking forward to seeing what next year brings, both for ourselves and for the birds of Rockabill!

All the best,
Brian & Donnacha

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