The dark side of Rockabill..... (Tystie picture gallery)

So it's no secret that our main focus out here are the Terns - all three species nest on the ground and require some level of habitat management and general protection from us to ensure a successful breeding season. In addition to the Terns, we have two other very ecologically different seabird species to monitor - namely Black Guillemots and Kittiwakes. We spent last Friday afternoon recording and ringing our Black Guillemot chicks, so here's a bit more about them: 

Adult Black Guillemot (BB - picture taken under NPWS license)

A young Black Guillemot chick (BB - picture taken under NPWS license)

Black Guillemots (or 'Tysties') are a member of the Auk family - related to Puffins, Razorbills and Common Guillemots, and they fill the same ecological niche in the northern hemisphere as the penguin family does in the southern hemisphere. They have a small, fine, pointed bill, short oval-shaped wings with white patches on the upper-wing and a noticeably tubby body (particularly noticeable then they're chicks!). Their legs and feet are a crimson red, as is the inside of their mouths.

Black Guillemot with food (left) and it's 'cousin', a Razorbill (right) (AP - picture taken under NPWS license

  

Black Guillemots outside the boulders area in which they nest. (AP - picture taken under NPWS license)

A range of Black Guillemot nestboxes on Rockabill.

On Rockabill this year we have 60 pairs breeding on both the Rock and the Bill. They prefer to breed amongst boulders and in crevices, so we put out L-shaped boxes for them on Rockabill that mimic this sheltered, cave-like preference. As well as amongst boulders and in specially designed nestboxes, we have Black Guillemots nesting in a number of wall holes around the island, occasionally peeking their head out when they hear a disturbance. They also nest in small holes, some specially designed, in piers and ports around Ireland.

Black Guillemot sticking its head out of its nest-hole. (BB - picture taken under NPWS license)

Black Guillemot eggs under boulders on Rockabill
(AP - picture taken under NPWS license)

Black Guillemots usually lay clutches of 1 or 2 eggs. When our Tern and Kittiwake chicks are old enough to fledge, they will still hang around on Rockabill on the outer parts of the colony. By contrast, when Black Guillemot chicks fledge they do so in the middle of the night - clambering out of their nesting holes and boxes until they reach the sea, and moving off before sunrise - so we don't actually get to see them again until they hopefully return in a couple of years time to breed here themselves.

A Black Guillemot chick, less than a week old (BB - picture taken under NPWS license)

Andrew with a BG chick.

Brian with a BG chick.

BG chick, close to fledging.

BG chick, close to fledging, having its wing measured.

Some BG nest-holes are quite deep....it can be hard to find the chicks.....

Black Guillemot chick, very close to fledging and looking very similar to an adult. (BB - picture taken under NPWS license)

In summer they come to our shores and islands to breed in 'loose' colonies, usually foraging within a few kilometres of those sites, but in winter they can move further out to sea - though generally don't migrate too far away.  During the breeding season they face a number of threats including predation by rats and mink, human disturbance close to the breeding site, offshore developments in foraging areas, and water pollution. Later in the year prolonged and heavy storms also pose a serious threat. The terrible storms in winter 2013/14 unfortunately killed a lot of birds that were feeding out at sea, and Black Guillemots that were born and ringed on Rockabill were found washed up on the west, north and east coasts of Ireland, giving us a interesting glimpse into their winter movements. Those storms almost halved the Rockabill population of Black Guillemots, and it will take several good years to get their numbers back.

Black Guillemots catch food by 'pursuit-diving', propelling themselves through the water using their wings. In this part of their range they eat a number of marine fish and crustaceans, depending on what's available, and usually stay within a couple of kilometres of the breeding site. Once their chicks hatch they are mostly fed 'butterfish' - a small eel-like fish found amongst rocks and seaweed. 

Adult Black Guillemot with a 'butterfish' to feed to its chicks. (AP - picture taken under NPWS license)

Butterfish - preferred food of Black Guillemot chicks (BB)

From late July onwards they change from being predominantly black to mostly white - we get to see the start of that change here on Rockabill......

Adult Black Guillemot starting to come into winter plumage (BB - picture taken under NPWS license)

The numbers are in.....great news!

Apologies for the lack of updates - most of our nests have chicks now so its absolute chaos out here, in the best way possible! Every morning and evening we spend several hours ringing chicks and taking weights and wing lengths so we can analyse their growth rates. Thankfully, this season looks to be going a bit better than last year in terms of chick survival, so fingers crossed that continues to the end of the summer!

We also found the time to do the second part of our nest census, to count all of the nests on the island, and the results are in......

Roseate Terns

Roseate Tern (picture taken under NPWS licence)

Numbers of Roseate Terns breeding here over the last two years have been levelling out a bit as the island reaches maximum capacity. With that in mind we would have been happy with similar numbers to last year's 1,250 pairs. You can imagine our delight then to get a final count of 1390 Roseate Tern nests this year!! That's the highest number every recorded here, a jump of almost 150 pairs from last year, further cementing Rockabill's importance as the single biggest Roseate Tern colony in Europe! Woo!

It's worth noting that around 90% of the nestboxes we put out have Roseate Tern nests in them, so a big thanks to everyone who has donated to the Seabird Appeal this year to help us get new boxes for future years, and to the staff and pupils of Balbriggan Community College for the boxes they gave us this year!

Common Terns

Common Tern (picture taken under NPWS licence)

 Last year we had around 2,100, and like the Roseates we have been getting the impression over the last few years that their numbers have been levelling off as all available space gets filled. This year we have 1,950 pairs of Common Terns, so their numbers here are down. Needless to say we still have a lot of them! And they still do an excellent job providing a bit of security for the Roseates. And with the amount of peck and poo attacks we're getting, it certainly doesn't seem like their numbers are any lower!! 

The Common Terns in Dublin Port seem to be doing quite well too, so despite the bit of a drop in numbers out here, they should be ok!

Arctic Terns

Nesting Arctic Tern (picture taken under NPWS licence)

 Last year we had somewhere in the region of 30 Arctic Tern nests at any one time, down from around 100 only a few years ago, due to gull predation. Unfortunately the Arctics tend to pick the rockier parts of the edge of the colony, as well as our neighbouring island ('the bill'), where they're easier pickings for opportunistic predators than if they were in the middle of the colony. We had somewhere in the region of 50 nests last week, though some of these have since been lost to gulls again. There is a ray of light though as we do have some Arctic chicks that are growing and surviving quite well. Last year we none of their eggs progressed to hatching, so this year is a bit of an improvement. We're also learning from our RSPB colleagues on Coquet Island in the UK on how to deal with the issue of gull predation, so the future should be a bit brighter in that regard. Like the Common Terns, Arctics aren't doing too bad in Dublin Port either, so fret not!

Black Guillemots

Black Guillemot (picture taken under NPWS licence)

Some of our followers might remember that last year our Black Guillemot population nearly halved due to high mortalities in the strong winter storms of 2013/14. Numbers this year are up to 60 pairs, up by around 5 pairs. A lot of young birds are likely to have died that winter, so we were expecting to 'recruit' less birds into the breeding population for a few years. Still, 60 pairs of these fantastic birds is still pretty good - fingers crossed for a few easier winters though!

Kittiwakes

Kittiwakes (picture taken under NPWS licence)

220 nests - our highest every count on Rockabill! We're delighted to have more of these fantastic cliff-nesting gulls. A lot of other colonies in the Irish Sea have noted decreases in their Kittiwake populations, so at least the Rockabill populaton is going strong.

So yay! Record-breaking years for both Roseate Terns and Kittiwakes, and not bad years for everything else. We have to send a big thanks to Peter Cutler, Jennifer Lynch, Niall T. Keogh and Dr. Steve Newton for their help over the last two weeks, both for censusing and ringing. After a few tough days you can imagine our delight when Jennifer brought us out some chocolate brownie cake, and Eoin from Skerries Seatours brought us out two Apache pizzas!! We'd like to think we've earned them!  

Andrew, and pizza!! (picture not taken under NPWS licence....)

Rockabill Roseate Record broken!! (...and we need 20secs of your time...)

So, we won't know the final figures until the end of next week, but we have some exciting news - We've already broken the record for the number of breeding Roseate Terns on Rockabill!!! Last year's record total was 1250 pairs, but we already have over 1300 nesting here at the moment!

This is fantastic news as Rockabill is the biggest colony of Roseate Terns in Europe. We have around 80% of the north-west European population of the species, so their success at Rockabill will help safeguard their future in this part of the world. As usual, nestbox uptake is very high, with many others nesting in the shelter behind, beside or between boxes.

This fantastic news is down to the hard work put in by a long list of people over the years, but we also have to mention another very important contributor - the EU Birds Directive. Rockabill is a 'Special Protection Area (SPA)' for Roseate Terns amongst other species, since such important numbers breed here. This designation essentially means no damage can be done to the site that might negatively impact their numbers. The Birds Directive also ensures successive governments make the conservation of our wild birds a priority, for example by providing funding for the Rockabill project through the NPWS. Unfortunately, the Birds Directive is under threat, despite doing so much through the years..........

BirdWatch Ireland has launched a campaign to defend the Birds and Habitats Directives - probably the most important campaign we have ever done. You can help by signing the petition at this link. It takes 20 seconds to fill in first name, last name, email and hit submit:

 http://www.birdwatchireland.ie/Supportus/SaveourNature/tabid/1461/Default.aspx

 

If the Birds and Habitats directives are weakened, it will mean that our Irish Nature laws will be weakened, and our wildlife and habitats will suffer. Rockabill is a great example of the effectiveness of the Directives, but they protect a number of other Irish seabird sites, as well as many of the rivers and lakes used by birds and wildlife in the summer and winter. 

Another example is the Corncrake, which has been saved from extinction because of these laws. Small populations of this once wide-spread bird are beginning to come back in the west and north-west of the country. 

And there are many more benefits.

The European Commission has been tasked by its President Jean-Claude Juncker to undertake a review of the Directives with the possibility of merging them. We believe, (as does BirdLife International, World Wildlife Fund for Nature, and the European Environment Bureau along with eNGOs all over Europe) that this is in fact an attempt to weaken the Directives as the push is for economic growth at all costs. As part of the Review, the Commission must undertake public consultation and in this case it is in a form of a questionnaire. Along with BirdLife International etc we are asking people to sign the petition/questionnaire that we have developed which has all the answers filled in already that are most supportive of the Directives.

 It takes 20 seconds to fill in first name, last name, email and hit submit.

http://www.birdwatchireland.ie/Supportus/SaveourNature/tabid/1461/Default.aspx

New Arrivals on Rockabill!

Our first Tern chicks have hatched!!

Last weekend we finally had our first hatchlings - Black Guillemot and Oystercatcher chicks (blog post on it here). Unfortunately the Oystercatcher chicks were attacked by nearby adult Common Terns and didn't survive, but on a brighter note we now have 10 Black Guillemot nests with chicks, and another 40 or so to come over the nest few days and weeks!

Black Guillemot chick. (Picture taken under NPWS license)

...which will grow up to look like this eventually! (Picture taken under NPWS license)

With the knowledge that Tern chicks take around 23 days to hatch, and the fact that we found our first few Tern eggs around 23 days ago, we've been on high alert to find the first Tern chicks.  Once they hatch we have to weigh and measure a subset of them every day, as well as ring them and track their survival. This morning we saw our first Roseate Tern egg 'pipping' - i.e. the chick was starting to break out, and by this evening we had four tiny Roseate Tern chicks as well as three Common Tern chicks!

A Roseate Tern chick on 'Day Zero' i.e. the day it hatched. (Picture taken under NPWS license)

Common Tern chick on 'Day Zero'. (Picture taken under NPWS license)

Two Common Tern chicks from above - well camouflaged against the ground. (Picture taken under NPWS license)

Common Tern chick. (Picture taken under NPWS license)

Chicks of both species tend to sit fairly still for their first day or two - not venturing out of their nest scrape. After that the Common Tern chicks will be running all over the place, whilst the Roseate Tern chicks will stay hidden in their nestboxes or in the nearest bit of shelter they can find. They'll grow very quickly over the next four weeks, changing shape, appearance and behaviour until they're finally able to fly. We'll do a blog post later in the season to illustrate the changes they go through.

As well as that exciting news, we've also been doing the first part of our nest census over the last two days - counting every nest on the island to establish how many breeding pairs of birds we have - and we've already broken the previous Rockabill records for two of our five species!! And we havn't even done the second part of the nest census yet!

Stay tuned later in the week for details!