Thursday, 29 September 2016

Rocky year for Roseates on Rockabill

Apologies for the major radio silence - the end of the season is one of our busiest times on Rockabill (along with the start of the season, and the middle of the season...) and after that followed our reintegration back into normal society, followed by a couple of weeks of data analysis and report writing! With all of that behind us we're now in a position to tell the story of how the biggest colony of Roseate Terns in Europe got on this year.

Roseate Terns on Rockabill, Summer 2016. (picture taken under NPWS license)

Large seabird colonies are all about life and death - Adults have to survive the winter and many undertake epic challenging migrations in the hope of reaching the colony, finding a mate and raising chicks. Many mate and produce eggs, which don't make it to hatching because of predation or harsh weather. Others manage to incubate and protect their eggs long enough for them to hatch, only for the chicks to die somewhere in the month or so it takes for them to grow feathers and begin to fly, again with predation and harsh weather the typical causes. Perhaps most heart-breaking of all is when adults pass all those hurdles of protecting their eggs and raising the chicks until they can fly, only for those fledglings to be predated soon after.

Roseate Terns early in the 2016 breeding season on Rockabill  (picture taken under NPWS license)

Roseate Terns on their nestboxes early in the 2016 breeding season  Rockabill. (picture taken under NPWS license)

We take it for granted that birds and mammals raise chicks and cubs every year, but sometimes we forget the gauntlet of challenges and hurdles they have to overcome to do that. Some, like many garden birds, have evolved to live short lives and aim to produce big numbers of offspring every year by laying lots of eggs and having more than one brood per summer. Others, like most seabirds, live long lives and put their time and energy into raising one or two chicks per year. Both strategies mean that their populations should be able to persist through a bad year or two, hopefully compensating with a good year or two or at least plenty of 'average' years. With that in mind, was this a good or a bad year for our Roseate Terns?



The Good:
Regular followers of the blog will remember the very pleasant surprise we had in late-June that the number of breeding pairs of Roseate Terns on Rockabill had risen by around 200 pairs to over 1,550. Given that Rockabill holds the biggest numbers in Europe this was a very welcome boost, and together with the work we're doing as part of the EU LIFE funded project with our partners in the RSPB and the North Wales Wildlife Trust it should help us secure they're future in this part of the world over the coming years.

In addition to that, the number of eggs laid by each pair was normal (I mean that in a good way!) and hatching rates were high too. We put out around 750 nestboxes and over 90% were occupied, the highest occupancy we've recorded to date! So there was plenty of good news by the middle of the season.

Roseate Tern sitting on its two eggs on Rockabill, Summer 2016. (picture taken under NPWS license)

Our new ring-reading hide, terracing and nestboxes, Summer 2016. (picture taken under NPWS license)

The first Roseate Tern egg on Rockabill in 2016 (picture taken under NPWS license)


The Bad:
It was around late June when our first Roseate chicks began to hatch, and unfortunately that's where the good news for this season ended. It very quickly became apparent that chick survival was going to be low. In almost all nests with two chicks the younger sibling died within 4 or 5 days. We weigh and measure chicks on a daily basis and this confirmed that growth rates were well below what they should be. During our chick-feeding studies we usually see the older chick getting two thirds of the food, with the younger chick managing to get some when the big chick is full. This year the older chick was never full however and kept competing for any incoming food, at the expense of the smaller chick. Our final tallies revealed that Roseate Tern productivity, i.e. the average number of chicks fledged per pair, was the lowest we've seen it on Rockabill with only 6 or 7 chicks surviving out of every 10 nests. Last year we ringed around 1500 Roseate Tern chicks whereas this year we ringed around two-thirds of that, despite having more pairs breeding this year.

A 'blonde' Roseate Tern chick on Rockabill, Summer 2016. (picture and handling under NPWS license)
Roseate Tern fledgling and parent on Rockabill, Summer 2016. (picture taken under NPWS license)


The Future:
I started this blog during the 2014 season and anyone following it since then might think this all sounds very familiar. The results of the 2014 season were very similar to 2016. Thankfully last year everything went well and breeding numbers and chick survival were all high. Those good years balance out the bad years, and it's because we've had a lot more good years than bad years that the Rockabill population of Roseate Terns has continued to grow since we started this conservation project in 1989. The frequency of bad years due to lack of suitable fish prey (2 of the last 3) is certainly cause for concern. It doesn't mean next year won't be fine, but how long until we have another bad year again? Were these temporary anomalies in suitable fish-prey numbers in the Irish Sea or are we seeing the start of a larger problem? Only time will tell.

Roseate Terns gathering on the edge of the colony at the end of the season (picture taken under NPWS license)

Earlier in the season we knew that Little Terns didn't even attempt to breed at their usual colony at Baltray in Louth, further north in the Irish Sea, and local fishermen commented on the lack of Sandeels in the area. Tern colonies at Dublin Port, Dalkey and Kilcoole all had a poor year too. Issues of predation played a larger part there, but there may have also been a lack of food. Thankfully our colleagues at Tern colonies further afield in the Irish Sea reported good years overall. Long-term and widespread monitoring  helps us see the bigger picture not only about our seabird populations, but the ecosystems and species they rely on and exist with. With that in mind we learned a lot in 2016. It'll be interesting to see what 2017 brings!

Saturday, 30 July 2016

Come Fly With Me

After most of our Terns laid eggs in late-May and early-June, and they take around 22 days to hatch and another 28-30 days to be able to fly, we're now coming to the end of the Tern breeding season here on Rockabill. While we do still have some chicks around that have a bit more growing up to do, we have far more that are able to fly and have left the area where their nest was. Our Common Tern fledglings tend to congregate on large 'obvious' areas like the helipad or on some of the shed roofs, where they can be easily found by their parents and they can readily spot any incoming food that's either intended for them or another fledgling from whom they might be able to steal it off! Our Roseate Tern fledglings on the other hand to to stay a bit closer to their parents and hang out on the rocky parts of the edge of the island.

Some of our Rockabill Roseates have moved on already however, with sightings from elsewhere in Dublin and even as far south as Wexford already. Conversely, we've seen some fledglings from Lady's Island in Wexford here on Rockabill, with the birds from there tending to move north for a while after the breeding season before beginning their southern migration next month. So if you live on the coast keep an eye out for Terns on the move!

Productivity, that is the number of chicks that fledge per nest, hasn't been great this year on Rockabill with many chicks seemingly dying due to lack of food. But seeing the chicks that we've worked hard to protect and monitor take their first stumbling flight and even become experts in the air after a few days has provided a very welcome boost to morale as the season draws to a close!
Fledgling Common Tern on the Rockabill helipad.  (picture taken under NPWS license)


Fledgling Roseate Tern  (picture taken under NPWS license)

When it comes to ID'ing the two fledglings Roseate Tern fledglings are a little but smaller than their Common counterparts, and are generally darker in their feathering, with black legs and a black bill. Overall they bear a closer resemblance to Sandwich Tern chicks, despite not being particularly closely related to them. Common Tern fledglings have a mostly orange bill with pink-ish legs and warmer brown and light grey colours to their plumage.

Fledgling Roseate Tern calling out to its parents  (picture taken under NPWS license)


Common Tern fledgling  (picture taken under NPWS license)

Fledgling Roseate Tern and adult  (picture taken under NPWS license)

Fledgling Common Tern begging for food.  (picture taken under NPWS license)


Fledgling Roseate Tern on Rockabill  (picture taken under NPWS license)



Fledgling Common Tern having a rest in between meals. (picture taken under NPWS license)
Below are two videos of a Roseate Tern chick and parents. This chick is days away from fledging and can be seen making rough attempts at flight to get on top of the nestbox! Many of our Roseate Terns practice their flying skills in a similar way before eventually getting the skill and confidence to fly out of the nesting area. 






Wednesday, 20 July 2016

The Dalkey Tern - We have Roseates breeding!

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

We have some mixed news since our last update, having had such large numbers of nests and chicks on Lamb Island; it went very quiet around the July Bank Holiday Weekend. By Tuesday 5th July there were only 16 Adults and about 4 chicks on Lamb Island, many of the first chicks should have been old enough to fledge at that stage but many nests/eggs were predated. The main culprits are rats, Hooded Crows and possible large gulls. Although the numbers were down on Lamb they are up on Maidens’ with 7 new clutches with 10 eggs and 1 chick and 160 adults on 14th July. 2 Roseate Terns were seen at the public event on Tuesday 5th, hopefully the start of many visitors from Rockabill. On 14th July, when hopes of breeding Rosies had faded a pair of Roseates had laid an egg in Box 5 on Maidens’ Rock. Maybe not great prospects of a successful fledging for that egg/chick but they are here and will hopefully come earlier next year with a few companions.
This is still a record year in terms of total terns present during the breeding season.

Roseate Tern egg on Maiden's Rock, 14th July.
  Photograph and egg handling carried out under NPWS licenses.

Ringing
On 21st & 27th June & 6th & 14th July myself and a few ringers, Steve Newton, Niall Tierney & Ricky Whelan got out to put leg rings on 54 chicks (6 Common) with 15 big enough to get a colour ring too. Hopefully we will be able to see these guys if/when they return in 2-3 years.
Ringing in progress on Lamb Island with Niall Tierney, RIcky Whelan and Steve Newton.
Ringing and photo carried out under NPWS licenses.
Public Events
The Tuesday evening and weekend events are going great, even when bad weather is forecast we got rainbows. 

Tuesday evening Rainbow Watch over Dalkey Island!

The BWI South Dublin branch has joined the Tuesday evening events (it’s been their event for years now) for July. I set up from 5pm then they all join from 6:30-8pm. It’s great having so many sets of eyes with local knowledge there to check every bird and inform the public.

Tuesday evening Tern Watch event with South Dublin BWI branch.

Weekend guided nature walks on Dalkey Island.

Saturday, 16 July 2016

And now for something completely different...

Our work changes a lot between various parts of the season - there's a lot of vegetation to be cut in May, a lot of eggs to be counted in June, chicks to be weighed and ringed in July and nestboxes to be scrubbed in August! One standard throughout the whole season however are our nest checks. Every morning and every evening we have specific study areas around the island that we visit and record any changes since our last visit - new nests, new eggs, chicks hatching, chicks dying etc etc. so that we have a few hundred 'nest histories' for each season. 

I was somewhat surprised by one nest in my study area earlier this summer as it appeared to be a Roseate Tern egg in a site I knew had been used by Commons in previous years. The egg was a 'typical' Roseate egg however and the location did offer some degree of shelter and so could conceivably have been picked out by a Roseate. A second egg was laid, again a typical Roseate egg and a little reconnaissance from a distance confirmed it was a Roseate Tern sitting on the eggs.


Then, last week on one of my nest rounds I saw that the first of the two eggs had hatched - that is the first of those two typical-looking Roseate Tern eggs that had been incubated by Roseate Terns for all those weeks. The only problem was that it had a fluffy appearance and pink legs among other features, meaning it was a Common Tern chick! 

A few days later and the second egg hatched - another Common Tern chick I hear you ask? Nope! A Roseate Tern chick! So this pair of Roseate Terns ended up with a brood of one Common and one Roseate Tern chick. There were no nearby nests that an egg could have been stolen or even accidentally rolled from, so the whole thing is a bit of a mystery! The adults are blissfully unaware however and are dutifully feeding their Common Tern chick as if it was their own - which I suppose it is now anyway! Given the similarities between the two species, particularly their diet, this chick stands as good a chance as any of fledging in the not too distant future!

Here are a couple of videos from this unusual nest - the larger and more active chick is the Common Tern and the smaller chick with a 'spiky' appearance is the Roseate Tern chick.








Monday, 11 July 2016

LIFE on Rockabill

Another busy week! Having thousands of birds on Rockabill is fairly standard over the summer months, but this week we had loads of people out here too! Given that there's usually only two of us out here, a bit of social interaction at this stage might be no harm as we we look to ease ourselves back into society at the end of August!

First of all we were visited by the Roseate Tern team from RSPB Coquet Island - Paul Morrison, Wes Davies and Tom Cadwallender. Coquet Island lies off the Northumberland coast in England and is home to 102 pairs of Roseate Terns (and counting!). The Coquet team's visit was facilitated by the current EU LIFE project to protect and expand the breeding range of the Roseate Tern in Ireland and Britain, and provided a great chance for the Rockabill and Coquet teams to meet up and 'talk Terns' and exchange knowledge on how we can continue to improve the fortunes of the Roseate Tern.

Check out the Coquet Island twitter account and website to keep up to date with all of the goings-on at Coquet and to see a live feed of how their Roseate Terns are getting on:


The Rockabill and Coquet Roseate Tern teams together for the first time.

It was also a great chance for the Rockabill team to sample the "Roseate Tern IPA", made by the 'From the Notebook' label which is on sale in the UK and from which a portion of sales go directly to the Roseate Tern project on Coquet. The label features a beautiful picture of a Roseate Tern with Coquet Island in the background, a short description of the species and it even has a pink/roseate cap! I had heard of the Roseate Tern IPA a couple of weeks ago, and let's just say it lived up to expectations!

Roseate Tern IPA on Rockabill!
The Coquet guys left on Thursday and on Friday we were delighted to welcome another group of visitors on Friday. It was great to meet Daniel Piec and Chantal Macleod-Nolan who are overseeing and co-ordinating the Roseate Tern LIFE project as part of the RSPB, as well as wardens and staff from a number of Tern colonies in Northern Ireland and Wales who came to see how we do things on Rockabill and how successful our work has been to date. (and Paddy from Kilcoole came out too, just 'cos Rockabill is the place to be!).

Given that every tern colony is different it was great to hear about other colonies and how they're faring this season, the different mix of species that each colony has, and the different problems each colony has and how they're tackled. These kinds of information-exchanges, however formal or informal, can be really valuable in the long run. Hopefully our visitors left with a renewed enthusiasm to attract Roseate Terns to their own colony and help this fantastic seabird become less rare in the coming years!

To keep up to date with the Roseate Tern LIFE project check out the facebook and twitter pages at the link below:
Our guests getting a tour of the island. (picture  by Daniel Piec)
The Rockabill team and our colleagues from the Roseate Tern LIFE project. (Pic via Chantal Macleod-Nolan & Usna Keating)

In addition to the Roseate Tern stuff we also had Saskia Wischnewski with us for most of the week. Saskia is studying seabird ecology at UCC and is currently carrying out work on behalf of Birdwatch Ireland which aims to look at where seabirds go to feed in the Irish Sea. She deployed a number of tags on our Kittiwakes and got some fascinating data with many of our birds heading far out to the north east in search of food to feed their chicks. 

Saskia removing a special tag that tracked the movements of one of the Rockabill Kittiwakes. Tag attached and picture taken under NPWS license.
And last but not least we had a changing of the guard recently. David Kinchin Smith has departed us to take up his dream job in the South Atlantic conserving birds on Gough Island - so his watch has ended. It was a pleasure working with David and on behalf of everyone here we want to wish him and Kilcoole's Em Witcutt the very best of luck on Gough and we look forward to tracking their progress in the coming months. 

Brian Burke and David Kinchin-Smith - Rockabill Wardens for 2016, just before David departed!

We are also delighted to welcome Shane Somers as the new warden on Rockabill. Unfortunately the Baltray Little Terns failed to breed this year, but Shane will definitely get his Tern-fix out here on Rockabill over the coming weeks and months! It's a big ask to begin work at such a large Tern colony in the middle of the season - the busiest time - but he has risen to the occasion and the Terns continue to be well looked after! 

Shane Somers- the new Rockabill warden! (pic by Matthew Byrne)



Friday, 1 July 2016

Rockabill Nest Census, Part Two

So last week we were delighted to announce that this year's count of Roseate Terns on Rockabill broke last year's record by around 150 pairs! We now have 1556 pairs of this fantastic seabird here, off the coast of Dublin. While counting our Roseate Terns we also carried out a full census of our Common Terns, Arctic Terns, Kittiwakes and Black Guillemots too! 


Common Tern (adult). on Rockabill, Summer 2016. (picture taken under NPWS license)
Our Common Terns have increased since last year, up by around 80 to 2029 pairs this year - good news after last year's slight decline. As well as being an impressive bird in their own right, their famous aggression (they're the ones constantly pecking us!) helps keep the more timid Roseate Terns safe - so the more of them we have the better.

Arctic Tern (adult) on Rockabill, Summer 2016. (picture taken under NPWS license)
Unfortunately our Arctic Terns continue to suffer from gull predation and so we have a maximum of around 60 pairs. The fact that they tend to nest on the peripheries of the colony, in places where Great Black-Backs can easily land and predate their eggs, make it very hard to estimate the exact numbers though in general we can surmise that they're not doing well. Hopefully they'll continue to do well in the Tern colonies in Dublin Port and on Dalkey Island!

Kittiwakes on Rockabill, Summer 2015. (picture taken under NPWS license)

Last year we had a record number of 215 Kittiwakes nesting on our cliffs and this year we have something very close to that number with what are called "apparently occupied nests". Unfortunately the Black-backed Gulls that cause our Arctic Terns such hassle have also become quite efficient at predating Kittiwake nests and as a result there are very very few active nests still left on the Bill, with some nests around Kitti-City on our main island suspected to have fallen victim to a similar fate. In the battle between the biggest gull in the world and the most beautiful gull in the world there's only one winner! 

Black Guillemot on Rockabill, Summer 2016. (picture taken under NPWS license)
Lastly, our Black Guillemots. In my first year on Rockabill our Black Guillemot population had halved from the previous year, owing to terrible winter storms in 2013/14. We had seen gradual increases in their numbers since then, though this year we have 61 nests which is two less than 2015. It seems likely that the vast majority of chicks fledged in 2013 were lost in those storms and so few if any were 'recruited' into the breeding population this year (they normally start breeding around 3 years old). If we can avoid any terrible winter storms again we're hoping the Rockabill population of this awesome Auk will come on leaps and bounds in the very near future.



So good news and bad news from the Rockabill nest census overall. After a hard few days of counting every single nest we were delighted to get a phonecall from Eoin of Skerries Seatours who soon arrived with chips and chicken wings from Ollie's Place in Skerries!! After two months out on Rockabill, needless to say we devoured the food in record timing! By this time of the summer a lot of our snacks have run out and we've been eating very similar meals on a daily basis, so this feast was a real morale booster. Our compliments to the chef! (and the boat man!)

A meal fit for a king - or two very hungry wardens!



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!