Friday, 25 July 2014

Black & White

It's been another busy week! Given how late in the season it is we concentrated on getting as many chicks ringed as we could. We have now ringed around 1,100 Roseate tern chicks, and a similarly large number of Common Tern chicks, that will help provide information in the future on the survival rate of chicks, their movement between Rockabill and other sites, and the lifespan of breeding birds. Just to serve as a reminder of the value of ringing we came across a Common Tern in the colony this week that had a ring from South Africa on its leg, rather than a BTO ring that would be used here and in the UK. We suspect the bird might have been ringed in Namibia, but we look forward to hearing the precise details of its travels in the near future!  A big thanks to the Birdwatch Ireland friends and colleagues - Dr. Steve Newton, Darren (of Kilcoole wardening fame), Susan, Paddy and Shane - that came out this week to lend a helping hand. We also had Paul Morrison, head warden on Coquet Island, the main/only Roseate Tern  colony in the UK and managed by the RSPB, who came out to take a look at how we do things on Rockabill and to lending a helping hand too! Take a look at some CoquetIsland's Puffins playing piano here (yes, you read that right).

Yours truly at work, sporting the latest in Rockabill fashion. (thanks to Karl Partridge for the picture)

So that was the Terns out of the way - we then moved on to our Kittiwakes and Black Guillemots because we want to know what they get up to too! Black Guillemots, as we've mentioned inprevious posts, nest in small caves/cavities/holes around the island, many of which are in walls and fairly accessible. Some, especially those on the Bill, are a bit trickier to find and get the chicks in...

It's in here somewhere.......

Black Guillemots take around 40 days to fledge, and when they reach that age they leave in the dark of night (to avoid predation). It looks like one or two of our Black Guillemot chicks have fledged already, but we still managed to ring the majority of chicks, of various ages and stages of fluffiness!

Black Guillemot chick - one of the more recently hatched ones we found (Picture taken under NPWS license)
Black Guillemot chick - another of the younger chicks we found (Picture taken under NPWS license)
Measuring the wing of a Black Guillemot chick - it doesnt yet have the 'clean' white wing patch of the adult. (Picture taken under NPWS license)

A Black Guillemot chick that isn't far off fledging (Picture taken under NPWS license)

Another Black Guillemot chick, not far off fledging (Picture taken under NPWS license)

Next were the Kittiwakes. Like the BG's they take a bit longer to fledge than the Terns do - they're bigger so have more growing to do! Given that they're in a nest on the side of a cliff, they stay pretty still until they're ready to fly so in that sense they were quite easy to deal with. Unfortunately, given that good grip is needed when standing on the side of a cliff, it means they have quite sharp claws! All part of the job though!

Adult Kittiwake and chick. (picture taken under NPWS license)

Part of the Kittiwake colony on the Bill - you can see why we didn't ring all of the chicks! (picture taken under NPWS license)
Kittiwake chick (picture taken under NPWS license)

Kittiwake chick (picture taken under NPWS license)

Kittiwake chick, have just gotten rid of some of its dinner..... (picture taken under NPWS license)

We got some of the more accessible Kittiwake chicks on both the Rock and Bill ringed, and we managed to trap some adults so that we could read their rings too. We got 5 adults in all, all of which were ringed on Rockabill as chicks: One 8-yr old, two 11-yr olds, a 14-yr old and a 17-yr old. We were also encouraged by the number of 2-chick Kittiwake clutches, and by the sighting of a couple of 3-chick clutches as well. And today we saw that the first few Kittiwake chicks have fledged and are exploring the waters around the island - so we ringed them just in time!

Reading the ring on an adult Kittiwake - he's not giving up the info without a fight! (Picture taken under NPWS license)

So - it makes for a short blog post but I can assure you it was a long and busy few days! The enjoyable kind of busy though - myself and Donnacha hadn't ringed either Black Guillemots or Kittiwakes before so it was great to get a chance to get the opportunity to work on that skill, as well as to get a close-up look of two fantastic species in the early stages of their development. We should also note that despite how cute and delicate they may look, both species have surprisingly strong bites,  and that the differences in diet between those species and the Terns was made very evident by the different smell left on our clothes at the end of the day!

So that's it for another week - more important breeding season work done that will pay dividends in terms of data and information in the years to come. A big thanks again to everyone who came out to help us during the week!

Friday, 18 July 2014

Cramped conditions in Kitti City!

From our recent blog posts you'd be forgiven for thinking that our Roseate and Common Tern chicks have occupied all of our time over the last few weeks and that we've barely had time for anything else. You'd be forgiven for thinking that, because you'd be correct!

A couple of thousand Tern chicks will keep you very busy it'd seem, but we have been taking the occasional glance at our Black Guillemots and Kittiwakes when we get the chance. Kittiwakes are a gull species that nest almost exclusively on cliffsides, building nests with mud, seaweed and vegetation. The chicks take around 43 days to fledge from hatching, so none have fledged yet, but they're quite big at the moment and still have a bit more growing to do. Needless to say space is usually limiting on the side of a cliff, so things are getting very cramped at the minute as the chicks grow bigger and start stretching their wings. 

We'll keep you updated on counts and fledging news, but in the mean time here are some pictures from a part of the east-side of the Island known as 'Kitti City':

Adult Kittiwake - or 'Black-Legged Kittiwake' to give its full name. (Picture taken under NPWS license)

Kitti City - not much space! (Picture taken under NPWS license)

We're so used to Common Tern chicks running around, and Roseate Tern chicks disappearing and reappaearing that it's nice to see some chicks that stay in the same place! (Picture taken under NPWS license)

Not much space, but at least they're sheltered from the weather. (Picture taken under NPWS license)

Some of the chicks are already close to adult-size, but they'll have some plumage differences for around two years before getting the clean and simple white and grey of the adults. (Picture taken under NPWS license)

Still some growing to do. (Picture taken under NPWS license)

 If you look closely there are actually two chicks in this nest. (Picture taken under NPWS license)

(Picture taken under NPWS license)

(Picture taken under NPWS license)
(Picture taken under NPWS license)

Monday, 14 July 2014

They grow up so fast!

It seems like only a short while ago we had our first eggs, nevermind our first chicks, and as this weekend we've had a few of our oldest Roseate and Common Tern chicks take to the skies! Over the past two weeks we've seen plenty of wing stretching, jumping/flapping on the spot and more recently some jumping on/off rocks accompanied by flapping to soften the landing - all a part of the development of the wing muscles and helping the chicks getting a taste of things to come. On Saturday night we found a Common Tern fledgling flying to heights of 2-3m (though not helped by the wind!), and yesterday during our feeding watch we had the pleasure of watching a lot of chicks flying for the first time!  Based on what we've seen they seem to start off by flapping, with a bit of running, and soon end up a metre or two off the ground - though their inexperience combined with their short tails means steering is still a bit of an issue! As the day went on we saw many get more and more adventurous, flying off and investigating the highs and lows around the area they hatched and grew up in so far - with their parents keeping a watchful eye on them. The island really takes on a new lease of life at each stage of the breeding season - going from a somewhat bare island, being filled up with nestboxes, eggs appearing everywhere, those same eggs turning into a huge number of fluffy chicks running around the place, and now those chicks learning to fly in preparation for the huge journey ahead of them in roughly two months time. 

As usual things are happening right on time. The oldest chicks we saw flying yesterday are around 28 days old, and have been undergoing rapid development over that time to change them from small, round and fluffy, to becoming much closer to adults in size, developing a more slender and elongated bodyshape that's more aerodynamic and suited to flying, and exchanging their insulating layer of fluff for feathers that will allow them to fly. Here are some pictures to illustrate what is quite a fascinating and dramatic change in such a short period of time:

Firstly the Common Terns:

Common Terns start off like this for the first few days - small and fluffy! (Picture taken under NPWS license)

After 3 or 4 days they start to look a bit more mature.....(Picture taken under NPWS license)

...their body shape starts to become a bit more elongated, and some proper feathers start to grow on the wings....(Picture taken under NPWS license)

...and the feathers keep growing as the chicks shed the downey 'fluff' they had before; they become noticeably more white and grey, which is how they'll look for the next two years - they're also bigger, longer and better at running! (Picture taken under NPWS license)

And this is our first Common Tern - first egg laid, and first to hatch - a few days before taking flight! Note the black head, white throat and mottled brown/grey wings. In terms of body shape they're now a small version of the adults and capable of flight! (Picture taken under NPWS license)

And Roseate Tern chicks undergo a very similar change process over the same time period, though Roseate chicks have a bit more of a 'spikey' appearance when they're very young:

Roseate Terns start off like this - small, and 'spikey' looking compared to the Commons. (Picture taken under NPWS license)

...then they get a bit bigger, head gets a bit 'longer' and they're less fluffy....(Picture taken under NPWS license)

...and that process continues, revealing the black cap and white body that it will have from now on, plus grey/brown wings (Picture taken under NPWS license)

And by the time they're able to fly for the first time this is what they look like, with a similar body shape to the adults (though a bit smaller), as we saw with the Common Terns. Quite impressive looking! (Picture taken under NPWS license)

In other news, we got a phone call on Saturday to say we were getting a food delivery! Imagine our surprise when 20minutes later we were holding a plate of spicy chicken wings, barbeque ribs, the largest burger either of us have ever seen, and not to mention all of the trimmings! So we have to give a very big thanks to the guys at the new Rockabill Restaraunt in Skerries (great name!) for the unexpected and delicious treat - that dinner has put a spring in our step for the next week! A big thanks too to Eoin from Skerries Seatours for dropping it out to us, not to mention looking after us with milk and biscuits in our times of need! For anyone wanting to get a closer look at Rockabill, get in touch with Eoin (Facebook page) for a boat tour around the island.

Lastly, our species list has finally hit 40 species! In the last two weeks we've had Redshank, Whimbrel and Purple Sandpipers - all wader species, probably individuals that didn't breed this year and have made an early departure from their summer grounds in places like Iceland.

So there we have it - an increasing number of the Roseate and Common Tern chicks on Rockabill are getting past the next hurdle in their lives and learning to fly! Our Black Guillemot chicks are still staying in their nestholes at the moment, but we'll have an update on our Kittiwake chicks later in the week!

Sunday, 6 July 2014

Food for Thought

For the last two Saturdays we've been taking it in turns to watch a number of Roseate Tern nests and record each feeding visit - the time, the box and the chick that got the food, the species of fish and the size of the fish ( in 'bill-lengths') - starting at 5am and continuing on until 10pm. Now I know what you're thinking - that sounds like a long day; what in god's name would make you do that? And the short answer is . . . . . . . . . our boss told us to!

Common Tern siblings fighting over a Sand Eel! (Picture taken under NPWS license)

The longer answer is that it provides important information on the food the chicks are getting this year - if productivity (i.e. the number of chicks that fledge) this year is low, we can look back at our data to see how this year's feeding was compared to other years - if there were less feeding visits than other years it could indicate that food was harder to find this year, if there were less of the birds preferred species and more of other species they only occasionally feed on it could be that food availability was poor this year, or if the food items being fed to the chicks were small compared to other years then maybe the quality of fish available was pretty poor. Given how important food availability and quality is in the survival of any birds - especially chicks, and especially to large colonies of birds/chicks - this is very important information to gather every year. Even if this year's productivity is okay it will provide a useful comparison for any poorer years in the future - more data that we can gather to help inform the future monitoring and conservation of the Roseate Tern.

Roseate tern with a Sand Eel to feed to it's chicks. Sand Eels are one of the most common food items for Irish Terns and other species such as Puffins and Kittiwakes. (Picture taken under NPWS license)

Roseate Tern adult with a Sprat to feed to it's hungry chicks - another common and important food item for Terns and other seabirds in Ireland. (Picture taken under NPWS license)

Unfortunately a lot of second and third chicks in Common and Roseate Tern clutches have died over the past week, despite the weather being largely favourable, so it could be that the adults are finding it harder to find suitable food in the area. The chicks weigh less than 100g for the first two weeks of their life, so any food shortage leaves them weak and unable to cope with cold or wet conditions. 

We have one more Roseate food watch and a few Common Tern food watches left to do before we have a complete dataset for the season. Fingers crossed the weather doesn't get too bad over the next week or two and that the adults manage to find enough food to keep the chicks going until it's time for them to fledge later this month!

Thursday, 3 July 2014

Ring-A Ring-A Roseate!

Part of our wardening job at the moment is to ring all of the chicks that have hatched - that is to put a small metal ring on their legs so that they can be identified later on. We're currently carrying that out across the island with the help of Dr. Steve Newton (BWI Senior Seabird Conservation Officer, and our boss!) and Mr. Ricky Whelan (Dublin Bay Birds Blog fame!). Common Terns get a BTO ring with a 7-character code (e.g. ST234575) on their right leg, and Roseate Terns get a BTO ring on their left leg and a special ring on their right leg. The special ring has a 4-character code (e.g. CF98) repeated twice on the ring which is easier to read than the BTO ring and thus makes it easier to gather data on this high priority species. The Roseate Terns from Lady's Island in Wexford are ringed in a similar way, except the BTO ring is put on the right leg and the special ring on the left leg - so if we see a Roseate with a special ring on its left we immediately know it's not from Rockabill.

Roseate Tern with a BTO ring on it's right leg, and a 'special' ring on it's right leg. (Picture taken under NPWS license)

At the moment the rings are very handy in identifying chicks - given how much they run around, hide and get mixed up with other chicks it means we know which chick we're weighing and measuring every day. Before the chicks hatched we spent several hours each day reading the rings on the legs of adults using a scope, which helps us gather data on the age profile of our breeding population, the survival rates of Terns that were ringed on Rockabill, and the immigration and emigration rates of birds born elsewhere breeding on Rockabill and vice versa. For example thanks to annual ringing efforts we know that a small percentage of breeding Roseate Terns in Lady's Island in Wexford were born on Rockabill, and a few Lady's Island born birds end up breeding here - and there's a much lesser rate of exchange of birds between Rockabill and Coquet Island in the UK.

All of this is useful data to help inform the conservation of Roseate Terns on Rockabill, and in Ireland and Europe, and hence we try and ring every single Roseate Tern and as many Commons as we can each year. Every now and again you get some very unexpected and interesting information from ringed birds however - the bird in the pictures below was ringed on Rockabill as a chick two years ago, and seen this year in Iceland!

A Rockabill Roseate in Iceland! Only the 2nd record of the species in Iceland. (Picture taken by Yann Kolbeinsson)

Now Roseate Terns carry out huge migrations each year, crossing many countries, but their journey takes them south to Africa - nowhere near Iceland! Roseate Terns are really considered a 'tropical' bird more suited to places like the Azores and the Indian Ocean, so the fact that we have them in Ireland is special enough - but that this one turned up in Iceland is very unexpected! It's only the second record of the species in Iceland, and was followed by a sighting of another Roseate Tern in western Iceland which was also born and ringed in Ireland (though the rings havn't been read yet - read about it Here). It often happens that birds get blown off course and end up in countries where they aren't native - we get a few American and mainland European birds blown to Ireland every year - but the question as to where exactly they came from usually remains a mystery. A big thanks to Gunnar Thor Hallgrinmsson, Yann Kolbeinsson and Sölvi Runar Vignisson for taking the time to read the rings and get in touch about their sighting!

In addition to that, in recent years Rockabill Roseates have turned up on a lake in Switzerland, a marsh in Central Poland and on the River Seine in France - none of which normally have Roseate Terns!

So ringing the Terns on Rockabill provides us with important information for the conservation from year to year, and occasionally allows us to shed some light on some of their more interesting adventures!