An Update from the Rock

Hello and apologies for the radio silence! Since peak hatching was reached we have been scrambling to keep up with the chicks' progress, leaving us little time for anything else. In the last week we've had our first fledglings take flight and things are becoming distinctly calmer around here,so it's high time we filled you in on the goings-on here.

A week after we said our sad goodbyes to our Coquet Island counterparts we re-embarked on our censusing mission. The combined results of the two censuses gave us an estimate of breeding pair numbers: 1,633 Roseate Tern pairs, 2,044 Common Tern pairs, and 53 Arctic Tern pairs (compared to 27 last year).

The team in action, photo courtesy of Brian Burke, taken under NPWS licence.

This year's ringing sweep was a Rockabill reunion, with Brian Burke and Shane Somers, two seasoned former wardens, returning to volunteer their time. Several days of concentrated ringing later and all but the most Houdini-like eligible chicks were ringed. All in all we ringed 1,608 Roseate Tern chicks, 1,826 Common Tern chicks, 5 Arctic Tern chicks and 79 Black Guillemot chicks. This number is still growing, as the younger chicks get to a size suitable for ringing.                                                     

 L: Common tern chicks queueing to be ringed. Photo Luíse Ní D. R: Heidi with an Arctic tern chick. Photo by Brian Burke, both taken under NPWS licence.

 It's not all terns! Black guillemot chicks: young chicks on left, chick on right 2 weeks or so down the line. Photos by Brian Burke, under NPWS licence.

 Since then we have begun ringing Kittiwake chicks, with 69 ringed so far. Steve also recaptured a sample of adult Kittiwakes to assess adult survival.

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More to come soon, 

Luíse Ní Dhonnabháin & the Rockabill Team.

             

Eggs, pegs and chicks with legs.

It's been a busy auld time around here on Rockabill as of late. We've had  a lot going on with visitors from Coquet Island being drafted into help with our Geolocator Tagging Study of roseate terns and also the epic task of censusing this here small but nest-packed island.

A retrieved Geo-locator tag (centre left of photo), records light level which can be used to calculate the latitude and longitude of the bird over it's long-distance migrations to and from West Africa.

Coquet Island is another tern colony located just off the coast of Northumberland, Northern England in the North Sea (https://www.rspb.org.uk/our-work/conservation/projects/coquet-island-seabird-sanctuary/). It hosts an impressive seabird colony hosting nesting birds such as: roseate, common, arctic and sandwich terns, black-headed, lesser black-backed, herring gulls, eider ducks, shelducks and more! The colony is taken care of by the RSPB, and Coquet island, like Rockabill, is also parts of the EU Roseate Tern Life Project.  (http://roseatetern.org/index.html).

Dr. Paul Morrison, Ibrahim Alfarwi (PhD candidate) and Dr. Stephen Newton landed on the Rock last Monday the 11th and after a brief coffee were put straight to work as we assembled our team and began the eggceptionally herculean task of finding every nest on the rock, counting every egg and marking all the nests. We searched through every patch of tree mallow, mayweed and scurvy grass as well as considerable number of nooks and crannies and 843 nestboxes. We were not disappointed! In total this exhaustive search yielded 1473 Roseate Tern nests, 1851 Common Tern nests and 63 Artic Tern nests.

After the initial census of Rockabill was completed it was time to re-trap all of the roseate terns that were initially tagged with Geo-locators last year. Ibrahim manned the hide on the south side of the island overlooking the nestboxes of the geo-locator birds, waiting patiently for birds fly in and out of boxes revealing their tags and relaying info to Dr. Steve and Paul who then caught 12 out of 20 of the tagged birds, a great result, though we hope to get some more in the near future when the boss man returns.

Steve attentively removing the Geo-locator tag while Paul takes note of ring and biometric data for a roseate tern. Image taken under NPWS licence.

Steve measures the wing length of a roseate tern. Image taken under NPWS licence.

Ibrahim and Paul out checking boxes. Image taken under NPWS licence.

Paul and Steve out retrieving tagged birds. Image taken under NPWS licence.

Now that everyone has left and Steve has headed for sunnier shores to liase with other members of the LIFE Project in the Azores as they visit the second largest Roseate Tern colony on this side of the Atlantic, time for the second census where the three of us will take on the challenge again and find the last of the nests. We're currently mid re-census and the numbers just keep climbing! Stay tuned for a final tally on the Rockabill Terns.

Oh and in other news are eggs have begun hatching en masse with many sorry little wet creatures emerging for the first look at the world but it doesn't take too long for them to dry off and tern into fluffy cute chicks that would just make your heart melt! It won't be long until these tiny cuties start legging it all around the place in force, in fact it's only going to be a day or two. Anyways that's all I got for now but we'll back again soon with more updates. Though if your bird senses are twitching and you're still looking for your fill on Rockabill life please check out the Instagram page "Birds_bats_and_beyond" for pictures of bird-life on the Rock (not affiliated with BirdWatch Ireland or anyone/thing else for that matter, all views my own if there even are any and please excuse this shameless self-promotion :D )

Two common tern chicks (Left:2 days old, Right 1 day old). Image taken under NPWS licence.

David Miley &
The Rockabill Team

Egg season

Yes, full egg season is upon us. Rockabill is teeming with eggs. Some of our main species, Roseate (Sterna dougallii) and Common (Sterna hirundo) terns have now laid their second and third eggs, respectively. Arctic terns (Sterna paradisaea) and Black Guillemots (Cepphus grylle) are also on their way and Black-legged Kittiwakes (Rissa Tridactyla), have just started… we still see them traveling around for some algae as nesting material, but some eggs started popping out!

Common tern (Sterna hirundo) with a three-egg clutch during nest checks. Photo taken under NPWS licence.

 Common terns get extremely protective and aggressive during this period. We miss the days we could walk the island peacefully! Now we are being attacked left and right, they peck our heads, our hands, poop on our heads and let’s admit it, sometimes on our faces too and scream in our ears. You have to admire their courage! They will do everything to protect their potential offspring. As Tim Birkhead says: “eggs are the most beautiful thing” indeed! Females invest so much on them, all their nutrients in the prior weeks before laying, the energy during the incubation period (shared by both partners in this case) and in protecting them from predators. During the process of egg laying, males will feed females. It is a funny thing to watch males coming into the colony holding fish in their bills and trying to find their partners. When they do find them, they sometimes still seem to tease them a bit before they actually feed them. I can definitely identify with the “hangry” (hungry + angry) females annoyingly screaming until fed, and sometimes after too, begging for more! Common terns normally lay 3-egg clutches in open nests on the ground. Roseates, on the other hand, generally lay 2-egg clutches in the wooden nest boxes provided, but that’s not to say that some Roseates will not lay open nests or just have the nutrients or energy for a single egg. Reproduction is a serious investment in the life of a seabird. If a bird needs to prioritize its own body condition of if reproducing during that season does not look favourable, for external factors, a bird will likely skip a reproductive year and try again the following season.

Roseate terns (Sterna dougallii) can be seen incubating eggs inside nest boxes provided. Photo taken under NPWS licence.

During egg season, one of our main worries is to keep the island predator free. Luckily here on Rockabill, we do not have to worry about any rodents (they would probably keep me off the island too!), but we do need to worry about gulls and birds of prey, especially Great Black Backed gulls (Larus marinus) and Peregrine falcons (Falco peregrinus). If given a chance, they predate on nutritious eggs, and sometimes on adult birds too, leaving a trail of destruction. For that, we have a gull scarer device, which plays distressing calls to keep gulls away, and we also do 5 AM shifts, when we try to keep the colony patrolled and busy and scare any attackers with our presence :)

Roseate egg predated just outside the nest box, likely by a Great Black Backed gull (Larus marinus). Photo taken under NPWS licence.

We are hoping for a very productive season, with many fledglings successfully leaving us at the end.  For now though, you can find us counting eggs around, under the Irish sunshine, wearing the most exotic three-layer head attires :)

That busy dinner hour! Common terns (Sterna hirundo) enjoy the Rockabill sunset while waiting for that take away fish :) Photo taken under NPWS licence.

Until next time,

Heidi Acampora

& the Rockabill team

Holding Court

Rockabill is alive with the sound of courting terns: shrill calls to mates, the helicopter-like warnings not to encroach on a particular tern's territory, females demanding to be fed... It's pretty loud!

Courtship in terns occurs in three main stages, with both sexes taking an active role in mate choice. The first stage takes place in the air, in circling displays above the colony. The aerial nature of this display may allow potential mates to size each other up, perhaps literally: there is some indication that the length of tail streamers in roseate terns is linked to reproductive quality, and may help terns decide on a suitable mate¹.

With wings spread wide and sunlight shining on them, terns can see how colourful each others flight feathers are. This may seem like an odd thing to say about a white/grey/black looking bird, but terns can see in the ultraviolet spectrum, and their newest flight feathers are covered in barbules which reflect this type of light. Terns are unusual in that they replace their flight feathers two and even three times a year. This happens slowly, and in overlapping stages, so that the second and third wave of feather growth can be seen at the same time. An abundance of new, “colourful” feathers may indicate good condition, and make that tern more attractive².

 Roseate terns strike a pose. Taken under NPWS license by Luíse Ní Dhonnabháin.

Terns pair off at the peak of this spiral, and after much displaying of the male's prized fish, he leads the female back to his nesting territory. Here after much synchronised posturing, the male hands over the fish to the female, after which they copulate for the first time (in common terns up to 50 copulations have been recorded for a single pair)³.

                   

Roseate tern pair mating. Taken under NPWS license by Luíse Ní Dhonnabháin.

In the second stage the pair head out to sea to feed, occasionally visiting the nesting territory.

In the final stage the female stays at the nest site while the male forages, bringing back food to the female while she lays the eggs. Some terns prefer to rob fish from their peers rather than head out fishing themselves. The time saved means that these terns can feed their mate more often, resulting in females with higher body masses and better outcomes for their fledglings. In spite of this, these kleptoparasites seem to make up only a small proportion of the colony's population⁴.

                                        

Roseate female wishes male would just hand it over. Taken under NPWS licence by Luíse Ní Dhonnabháin.

The arrival of the first eggs on Rockabill this week marks the end of the courtship period for the early birds, but there are still many more wooing away!

We hope you've been enjoying National Biodiversity Week, and made it to some of the programme's events. Until the next time!

Luíse Ní Dhonnabháin
& The Rockabill Team.

1 Palestis, B.G. et. al. (2012) 'Tail length and sexual selection in a monogamous, monomorphic species, the Roseate Tern Sterna dougallii' Journal of Ornithology , 153 (4).

2 Cabot D. and Nisbet I. (2013) Terns. HarperCollins:London.

3González-Solı́saf J., Sokolov E., Beckerd P.F. (2001) 'Courtship feedings, copulations and paternity in common terns, Sterna hirundo' Animal Behaviour, 61(6).

4 García, G.O., Becker P.H, Favero M. (2012) Kleptoparasitism during courtship in Sterna hirundo and its relationship with female reproductive performance.' Journal of Ornithology, 152(1).

Back in Action!

Hello everybody and welcome back to the Rockablog! A whole new season is currently just kicking off with a large flock of terns having arrived on the Rock on Thursday 3rd. It’s all hands on deck and the seasonal rush is upon us and we've deployed over 840 nest boxes around the island to accommodate all our guests! There are three of us wardening the island again this year Luíse O’Donovan, Heidi Acampora and myself, David Miley, returning for my second season on the Rock.

Lunch on the helipad. Photo Credit: Johnny Woodlock

We began work here 3 weeks ago with vegetation clearance of the thick mallow which covers many parts of the island, and requires thinning to make more space available for nesting Roseate, Common and Arctic Terns. We were massively assisted by Scout Leaders Declan de Freitas, Steven Stewart, Alan O' Kelly and Johnny Woodlock of Skerries Sea Scouts. Thanks a million, your hard work and sore backs are greatly appreciated gentlemen!

Scout Leaders Alan, Johnny and Steven enjoy the view after a hard days work, while Declan is still giving it socks, fair play Dec! Photo Credit: David Miley

Photo Credit: Johnny Woodlock

In rough weather some days there's only one way to get on the boat! Photo Credit: Johnny Woodlock

Dr. Stephen "The Ferryman" Newton our rower extraordinaire gets the lads onto the boat safe and mostly dry! Photo Credit: Johnny Woodlock

On Friday 4th of May we also received some very special guests from the mainland bearing very beautiful gifts for our Roseate Terns! Balbriggan Community College who have been producing nest boxes for the Rockabill Roseate Tern Scheme for the past 25 years and have produced over a 1,000 nest boxes, amazing work!!! 

Our student artisan crafts-people departing from Malahide for their trip to the Rock. Photo Credit: Sean Pierce.

Group photo time! Photo Credit: Sean Pierce.

That’s 25 years of present and past students, teachers and staff members that have been involved! Talk about making a difference to front-line conservation, their nest boxes have been present and providing shelters for nests and chicks of Roseate Terns for a quarter of a century as their numbers have soared from a meagre 189 pairs in 1989 to 1603 pairs in 2017. Below is the elegant and beautiful commemorative 25th Anniversary Box that Balbriggan Community College designed and produced:

"The Students of Balbriggan Community College have built and provided nestboxes for the terns on Rockabill since 1993." Photo Credit: Sean Pierce.

"Balbriggan Community College has co-operated with BirdWatch Ireland and has produced over 1,000 nestboxes for the Rockabill Project." Photo Credit: Sean Pierce.

"Many past pupils have been involved with the scheme organised by the school Woodwork Teachers: Mr. Harford 1993-2001, Mr. Macken 2001-2010, Mr. Boylan 2012-2018." Photo Credit: Sean Pierce.

"The huge increase in breeding numbers of Roseate Terns from 189 pairs in 1989 to 1600 in 2017, owes much of it's success to the nestboxes provided by the school." Photo Credit: Sean Pierce.

"Sponsored by Shearwater Sea Kayaking in 2018." Photo Credit: Sean Pierce.

Proudly waving the flag! Photo Credit: Sean Pierce.

Nestbox in the making! Photo Credit: Sean Pierce.

Final stop, Rockabill! Photo Credit: Sean Pierce.

Photo Credit: Sean Pierce.

Photo Credit: Sean Pierce.

Photo Credit: Sean Pierce.

A very special thank you to Balbriggan Community College for their continued and treasured support that they have provided for the Roseate Terns and the Rockabill Project over the years! Also a huge thanks to the 2nd Year Woodwork Class with Mr. Boylan, the Transition Year Art Class with Ms. Rossiter and Ms. Grant for design inputs. Beautiful boxes everyone ye really went the extra mile this year, we were really blown away by the creativity of this years boxes!

Things have been relatively quiet on the Tern front as the colony has been moving out sea and back onto the Rock on a number of occasions while they get settled, though they do seem to be really getting into the swing of things now with the colony starting to become very busy with at least 2,000-3,000 terns with us at the moment. We've yet to see our first egg on the island but I'm sure it'll only be a matter of days now.

Also folks there are numerous boats in the area out fishing, enjoying the weather and wildlife, a number which have attempted landings on the island, I'd like to inform people that landing is strictly limited to personnel authorised by The National Parks and Wildlife Services and The Council of Irish Lights and if fishing or taking photos around the island please refrain from landing or coming too close to shore that you cause disturbances to the Terns and Kittiwakes. That's all from us here on the Rock, we'll be back with more blog updates soon!

David Miley & The Rockabill Team