Thursday, 13 June 2019

Rockabill – Week Three – The Eggcitement Begins

As things get hectic on Rockabill we're playing catch-up with the blogs - keep an eye on here in the next week or two as we get you up to speed on everything that's been happening at one of Europe's most important seabird colonies! 

The arrival of our first eggs has brought a new wave of excitement to Rockabill!

Common Tern egg (left) and Roseate Tern egg in a nestbox (right) (E. Tiernan, photo taken under NPWS license)

The week started off slow, which was an unusual feeling for us wardens. During this time, we were treated to groups of Puffins, Razorbills and Common Guillemots around the island.
Puffin, Razorbill and Guillemot paying a visit to Rockabill (E. Tiernan)

It was certainly a “calm before the storm” situation. Barely two days after we finished fixing the last of the nest boxes in place, we started finding our first nests of Common Tern eggs. Each of us had found Common eggs in at least one of our study areas.

Common Tern eggs (top) and an adult Common Tern sitting back down on its clutch - note the coded clothes peg that we use to mark some of the nests! (E. Tiernan, photos taken under NPWS license)

We didn’t have to wait too long before we found the first Roseate Tern eggs. The first Roseate egg of the season for Rockabill was found on the 17th of May. By the 20th, Andrew and I found the first full Roseate clutches (we are still arguing over who found theirs first!!).

Top: Full clutch of Roseate Tern eggs Bottom: Roseate Terns incubating their eggs inside their nest boxes (E. Tiernan Photos taken under NPWS license)

We are now finding new nests and new eggs with every nest check. Our nest checks are performed each morning and evening to help us to determine a timeline for each egg. For the rest of the day, you can find us wardens in the hides that have been erected at different points around the island. We spend our afternoons between nest checks carrying out ring reading on all the Rockabill terns. 

Throughout the season we will be recording as many re-sightings as we can. Each trip down to our hides is fast becoming a dangerous obstacle course. Whilst Roseate Terns prefer to nest in sheltered areas (which is imitated by the many nest boxes), Common Terns nest in open soil or gravel. This means that throughout the week the Common Terns have been nesting in any cracks along the paths.

Top: Common Tern protecting it’s clutch of eggs on the path close by; Bottom Clutch of two common Tern eggs in a nest made in a crack in the path. (E. Tiernan Photos taken under NPWS license)

That’s all the news we have for you this week. Things are about to get much busier as we eagerly await the arrival of our first chicks.

- Emma & the Rockabill Team.

Thursday, 16 May 2019

Guest blog - The Terns have returned: an update on the Dalkey Islands Tern Project

With the arrival of the Terns to the Dalkey Islands, it’s been all hands - on deck getting the breeding sites ready for the upcoming nesting season. So far, we have counted 15 Terns (both Common and Arctic) on Maiden Rock and 5 Arctic Terns on Lamb Island. No eggs have been laid yet, although there’s plenty of courtship activity taking place with males arriving regularly with sandeels and sprat to their eager mates. While Roseate Terns have not yet made their presence known, we’re hoping that nest boxes on Maiden Rock and Lamb Island might entice a few pairs to lay down roots on the islands. Roseate Terns have bred on Maiden Rock as recently as 2016, so we’ll be keeping our eyes peeled over the coming season!

Map of the Dalkey Island complex

Oystercatchers, like the Terns, have also been busy, with two nests, (containing 3 eggs each), found on Lamb Island, and a courting pair spotted on Maiden Rock.

Oystercatcher nest on Lamb Island (Photo by Tara Adcock)

On Tuesday, the 14th of May, Steve Newton, the Dalkey Island Tern Conservation Project Manager, and I, set out for the islands. Our first stop was Dalkey Island, where we unloaded our gear before nipping across to Lamb Island as the tide fell, (some of us more nimbly than others, with Steve thoroughly putting me to shame!).

Steve effortlessly carrying canes from Dalkey Island to Lamb Island (Photo by Tara Adcock)

Our task for the day – creating a grid of alternating canes each approximately one metre apart on Lamb Island to try to deter Gulls from landing in the Tern colony and predating chicks and eggs. 

Setting up the cane grid on Lamb Island (Photo by Tara Adcock)

The idea behind this simple method is that at one metre distances, the canes are placed too close together for Lesser Black – backed Gulls (wingspan 135-150cm), Herring Gulls (wingspan 130-150cm) and Great Black – backed Gulls (wingspan 150-170cm) to land between, while still allowing space for the smaller Arctic, Common and Roseate Terns to fly into the colony. This was tried in 2016 on the Inner Farne and Brownsman Islands off the northeast coast of the UK with good success (Boothby et al., 2019). Fingers crossed it will help the Lamb Island subcolony over the upcoming season!

The cane grid on Lamb Island (Photo by Tara Adcock)

With a good proportion of the canes in place, it was time to head back to the mainland for the first Tuesday evening Tern Watch Event of the season. Johnny the boatman and his able navigator, Bowzer, were on hand to safely ferry us back across the Dalkey Sound.

Johnny, our salty sea captain and his able navigator, ‘Bowzer’ (Photo by Tara Adcock)

We were incredibly lucky with the weather for our first nature watching event and hopefully it’s a good omen for the upcoming season!

Some of the visitors to the first Tern Watch Event of the season (Photos by Tara Adcock)

In total, we spotted 17 bird and two mammalian species. The Terns were joined by diving Gannets further out to sea, and Razorbills and Manx Shearwaters on their way to and from their breeding grounds (telescopes, provided by BirdWatch Ireland, were a definite necessity for this spectacle!).

Closer to shore, a Black Guillemot pair, which are nesting in the wall of the harbour, bobbed on the sea before taking flight, their white wing patches startling against the jet black of their bodies. Cormorants basked, wings outstretched to dry, on the rocks between Maiden Rock and Lamb Island among roosting Gulls and Terns. Grey seals, ever curious, peeked above the water at passing boats, while rabbits were a common sight bounding across Lamb Island. 

The list of species recorded during the Tuesday evening event (Photo by Tara Adcock)

Finally, although not of the avian or mammalian persuasion, we were treated to the spectacle of this beautiful ship passing through the Dalkey Sound toward the end of the evening.

Ship sailing past Dalkey Island during the Tuesday Tern Watch event (Photo by Tara Adcock) 

All in all, it was a really pleasant night and it was great to see some familiar faces from last years season popping down again to check out the Terns!

Public goodwill and understanding are integral to the success of the project. The Dalkey Islands, being on the edge of an urban hub, are ideally located for showcasing the beauty and ecology of birds along with mammals such as seals and harbour porpoises. It also introduces people to the importance of projects such as the EU Life Roseate Tern Recovery Project, which the Dalkey Island Tern Conservation Project is a part of.

To this end, Tern Watch Events will continue to be held every Tuesday evening from 5 – 8pm at Coliemore Harbour, Dalkey until the 30th of July

Beginning June 2nd, morning Tern Watch Events will be held every second Sunday at Colimore Harbour from 11am – 1pm, followed by three, one hour Guided Walks on Dalkey Island from 2:30 – 5:30pm. 

A massive thank you to everyone who came down to the first Tern Watch Event of the season, and I look forward to many more inspiring morning and evenings over the coming months!


Boothby, C., Redfern, C., & Schroeder, J. (2019). An evaluation of canes as a management technique to reduce predation by gulls of ground nesting seabirds. International Journal of Avian Science, 161, 453-458.

Rockabill - Week Two - Numerous nestboxes!

The past week has been extremely busy! Since our last post we have cut the last of the Tree Mallow and spent our time organising nest boxes - some go into very precise locations to give continuity to our detailed nest monitoring in the various 'study plots' around the island. After that, it's a matter of filling nearly all available space to accomodate our burgeoning Roseate Tern population! Each box is placed firmly into the ground, with a stone weight put on top to ensure it doesn't budge for the next few months!

Roseate Terns making an early claim to the nestboxes (E. Tiernan, Photo taken under NPWS license)

Now that the manual labour is out of the way, the nest monitoring begins. We have divided the island into different study sites amongst ourselves. Like previous years, this consists of morning and afternoon nest checks to accurately age eggs and hatchlings, identify chicks to their parents and record the breeding success of the parents associated with each nest for both Roseate and Common Terns within our designated sites.

Roseate terns standing on their nestboxes (A. McManus, Photos taken under NPWS license)

The Roseate Terns are easily distinguishable with the jet-black beak and are usually observed perched on top of their nest boxes, while Common Terns have orange beaks with a black tip and can be associated with open nests, usually consisting of a small scrape in the ground.

That’s all the news we have for now - we'll have an update on our first eggs very soon!

Andrew & The Rockabill Team.

Friday, 3 May 2019

Rockabill 2019 - One week down, plenty to go!

A lone Common Tern against the evening sky (L. Gill)

We’ve finished our first week out here on Rockabill and it certainly did not disappoint. From Storm Hannah to the arrival of the Common Terns, it’s been an interesting week.

Waves breaking over the Bill during a bright spell during Storm Hannah. (L. Gill)

Kittiwakes on a ledge in 'KittiCity'
(L.Gill, photo taken under NPWS license)

Our bird species list is now at 21. Kittiwakes have started to occupy cliff ledges in KittiCity and KittiPoint along with in section 4C and out in the Bill.

Black Guillemots resting at the end of the pier (L.Gill)

Black Guillemots have also started to spend more time on the island rather than rafting up around it. Every morning we go out to count them and our highest count so far has been 213! 

Hopefully the majority of them will hang around to nest on Rockabill in the coming weeks.

Myself and Andrew have started to settle down into the routine of island life and getting stuck into our work. Emma, the third warden will be arriving tomorrow. 

All the study sites have now been cleared of tree mallow - these large plants cover up the nesting areas for the Terns, so at the start of the season we remove the majority of it to ensure we have space for as many Tern nests as possible on this small island! 


See the image above and to the right for a before/after of Tree Mallow removal from one of the Lighthouse Gardens - it makes a big difference! 

We have also taken out all the nest boxes from inside the house and sorted them in numerical order ready to go to their various parts of the island. Any nest boxes that were broken have been set aside to be repaired or replaced.

Some of the c900 nestboxes we'll be deploying around the island (L.Gill)

For birds that aren’t nesting in nest boxes, their nests will be marked with pegs. We took out all the pegs from last year and sorted them into Common Tern, Artic Tern and Roseate Tern piles. We then sorted all of the Common Tern pegs on bamboo sticks from number 1-250 and Roseate and Artic pegs will soon follow.

Last night we were treated to a beautiful sunset with Common Terns flying across making for some beautiful shots.

Sunset, with Common Tern silhouettes flying across. (L.Gill)
Sunset, with Common Tern silhouettes flying across. (L.Gill)

Lorna Gill & The Rockabill Team.

Friday, 3 August 2018

Away go the fledglings!

A group of well-grown common tern (Sterna hirundo) chicks and some adults gather on the rocks after a storm. Photo taken under NPWS license. Photo credit: Heidi Acampora.

Our season is coming to an end. In the last couple of days, many chicks have fledged, giving us that feeling of mission accomplished (well, almost!)! The island has become noticeably emptier of chicks, but still lively with adults, non-breeding birds, late chicks and some very late chicks! It is very entertaining to watch the older chicks practicing their flights, taking their first trips to sea, attempting to do some fishing around the edges of the colony and at the same time still being fed by their parents, and actually looking bigger and fatter than the parents themselves! Speaking of looks, although everyone loves a tiny fluffy chick, fledglings also look absolutely class! Common terns acquire this coppery and more blotchy tone to their feathers, while Roseates have a bit more golden and symmetrical tone to theirs. All absolutely beautiful in each of their phases!

A roseate tern (Sterna dougallii) chick far from its nest. Notice the golden patterns to the feathers. Photo taken under NPWS license. Photo credit: Heidi Acampora.

A common tern chick wanders the path in Garden 5. Notice the copper tone to the feathers. Photo taken under NPWS license. Photo credit: Heidi Acampora.

Now that chicks are fledging, we have been spending less time on biometrics (hard to catch birds that have learned how to fly!) and more time ring reading to assess survival, inputting all that precious data into the computer and monitoring some late nests. The weather has deteriorated a little in the past week (What? No more tropical island?!), which leaves us slightly claustrophobic, but happy about filling up our water tank! Soon it’ll be time to remove all nest boxes and markers and clean up the island for next year (then yes, it’ll be mission accomplished!). For now, we are enjoying our last few ‘tern’ moments for the year :) 
Here are some of my snaps of #LifeOnTheRock !

We also have black-legged kittiwake (Rissa Tridactyla) chicks, this one, particularly young. Photo taken under NPWS license. Photo credit: Heidi Acampora.
On the subject of late nests, this common tern chick is one of the latest in my study area. I wonder what it is saying! Photo taken under NPWS license. Photo credit: Heidi Acampora.
Practice makes perfect! An Arctic tern (Sterna paradisaea) chick practices its flight under his parent's evaluation. Photo taken under NPWS license. Photo credit: Heidi Acampora.
There has also been a lot of chilling, which I find it very entertaining to watch! Three common tern chicks and a roseate chick hang out on the pier wall, like all young folks do! Photo taken under NPWS license. Photo credit: Heidi Acampora.

And also a lot of eating! A Roseate parent brings dinner! Photo taken under NPWS license. Photo credit: Heidi Acampora.

An overview of 4B on a stormy day. Photo taken under NPWS license. Photo credit: Heidi Acampora.

And lastly, I'll leave you with a tern sunset. Photo taken under NPWS license. Photo credit: Heidi Acampora.

Heidi Acampora

& the Rockabill team