Wednesday, 12 August 2015

Plenty to see in the Irish Sea

Every summer Rockabill Island plays host to a lot of birds - 8,000+ breeding adults, roughly the same amount of chicks that hatch, and 52 species coming and going this year - and all on a small rocky island a bit smaller than a football pitch! But obviously Rockabill and its breeding birds are just one part of the large and complex ecosystem that is the Irish Sea. Being the keen zoologists we are, we're always delighted to spot some of the other 'charismatic' fauna that is to be seen around us.......

(...and we've sent records of the below species to the National Biodiversity Data Centre and Irish Whale and Dolphin Group....)


Earlier on in the season we had some excellent views of Minke Whales (which I had never seen before!) and a sizeable pod of Common Dolphins to our North. Andrew also spotted a Basking Shark a few kilometres to the East (not a cetacean I know..). Though these species were largely absent (or at least inconspicuous) from mid-June onwards, we have been treated to excellent views of several Harbour Porpoises close to the island throughout the season, including a calf swimming very close behind its mother. Needless to say we aren't used to seeing Porpoises in either Roscommon or Carlow, so each opportunity to watch these magnificent mammals was a real treat!

Harbour Porpoise.
Harbour Porpoise.
Harbour Porpoise.


Lions Manes proved to be the most common Jellyfish around Rockabill this summer, ironically followed by 'Common' Jellyfish in second, with a good number of the spectacular Compass Jellyfish making appearances from late June onwards. We had a few small Blue Jellyfish and the odd Barrell Jellyfish too, and a sixth species that we hadn't come across before (pun intended) - a Cross Jellyfish! (or what we think is a Cross Jellyfish, its surprisingly hard to get info on Jellyfish...)

Cross Jellyfish.
Compass (left) and Common/Moon Jellyfish (right).
Lions Mane Jellyfish.

Lions Mane Jellyfish (underneath).


Cetaceans can be hard to spot, and jellyfish come and go depending on the water, but we can always be guaranteed to be joined by a few Grey and Common Seals down at the piers. Though they were wary of our presence early on in the summer, they gradually grew more tolerant as the summer went on and allowed us some very confiding views. Watching their blubbery bodies hauled out on the rocks at low tide almost makes you forget how graceful and speedy they are once they get into the water. Once again - not many seals in either Roscommon or Carlow - so we took advantage of the few nice evenings we had to watch our mammalian neighbours with curioisity they couldnt help but reciprocate.

Grey Seal.

Grey Seal.

Grey Seal.

Common Seal.

Grey Seal.

Rock Pool Regulars!

We touched on the fantastic diversity in even the smallest rock pools in an earlier blog post (Here!), so we won't repeat ourselves except to encourage everyone to give them a closer look the next time you're beside the sea - you'll be surprised at what you might find!

Common Blenny ('Shanny') lurking amonst shelter in a rockpool.

Edible Sea Urchin.

Beadlet Anemone.

Brown Crab.
Common Shore (Green) Crab.
Dog Whelk.
Common Starfish.

Sunday, 9 August 2015

Rockabill Species List 2015, and the mystery of the Blackbird

Apologies for the lack of updates - plenty to be done as the breeding season draws to a close! Don't worry though, we'll get you up to speed with all of our end-of-season news in no time!

As well as tracking the trials and tribulations of our nesting species, one thing we like to monitor (being the keen ornithologists that we are) are the other species that visit Rockabill. The number of species we record varies from year to year, usually due to weather and surveyor effort. Years with lots of wind increase the chance that more birds associated with the mainland might accidently get blown out to Rockabill, and when there's rain or fog then birds that are migrating or simply flying by are more likely to land on Rockabill for shelter or to take a break rather than continue flying in poor conditions.

Surveyor effort also plays an important part - quite simply if you don't get out and look, you won't see anything! Each year the wardens make a list of the species they see, and there's always some friendly competition from year to year. When I started on Rockabill last year, the wardens from 2013 (Aine and Roisin) had recorded an impressive 51 species! So that was the number to beat.......or not beat as it turned out. Myself and Donnacha only managed to find 40 species from May to August last year. Well that just made me even more determined this year and Andrew was equally enthusiastic. So here is our Rockabill bird species list for this year.........

First we have the obvious ones - the birds that breed on Rockabill:

1. Roseate Tern
2. Common Tern
3. Arctic Tern
4. Black Guillemot
5. Kittiwake
6. Oystercatcher

Our ill-fated Oystercatcher nest. (B.Burke)

Then we have the other seabirds that breed on Lambay and other nearby islands:
7. Herring Gull
8. Great Black-Backed Gull
9. Lesser Black-Backed Gull
10. Common Guillemot
11. Razorbill
12. Puffin
13. Fulmar
14. Cormorant
15. Shag
16. Gannet

Other passing seabirds that don't breed nearby:
17. Manx Shearwater
18. Storm Petrel
19. Arctic Skua
20. Great Skua
21. Black-Headed Gull
22. Common Scoter

Wader species moving to and from their breeding grounds early and late in the season:
23. Turnstone
24. Purple Sandpiper
25. Dunlin
26. Knot
27. Whimbrel
28. Redshank
29. Lapwing

We have a small number of Turnstones with us on Rockabill for most of the summer. (B.Burke)

Purple Sandpiper - their numbers will build up as winter approaches. (B.Burke)

....and 30. Shelduck

A Shelduck on the Bill. (B.Burke)

Then the birds of prey coming out for food:
31. Peregrine Falcon
32. Kestrel (that didn't end well, click here to read more)

Peregrine Falcon (bottom) hunting a Common Tern on Rockabill, 2015. (B.Burke)
Kestrel eating a chick on Rockabill, 2015. (B.Burke)

We get the usual harbingers of summer that everyone looks forward to, and some less common migrants too:

33. Swallow
34. Swift
35. House Martin
36. Wheatear
37. Chiffchaff
38. Willow Warbler
39. Whitethroat 
40. Spotted Flycatcher
41. Blackcap
42. Grasshopper Warbler
43. Black Redstart

Grasshopper Warbler looking for food in a Roseate Tern nestbox. (B.Burke)
A House Martin rests on Andrews windowsill (A.Power)

Black Redstart in one of the gardens on Rockabill (A.Power)

Wheatear on the Bill. (A.Power)

Ortolan Bunting - the first record of this species in Dublin. (B.Burke)

Lastly we get other common species that are doing a bit of pre-breeding season movement and somehow or another end up 7km out to sea! This section of the list can vary a bit from year to year, and most of these birds were seen in May, with the birds usually wasting little time in returning to the mainland:
45. Collared Dove 
46. Racing/Feral Pigeon
47. Rock Pipit
48. Starling
49. Rook
50. Hooded Crow
51. Pied Wagtail

Racing Pigeons often stop off on Rockabill. (B.Burke)

So that would be 51 species, a big improvement on last year but the same as seen in 2013! We've listed the Rockabill breeders, the other seabirds that breed nearby or pass by, the birds of prey, the spring/summer migrants and the common species that got blown out accidently..........Thankfully we saw one more species - a female Blackbird - taking us to 52 species, 1 more than 2013!! 

The Blackbird that has appeared on and off on Rockabill all summer! (A.Power)

The reason I didn't put it in that last category is because it didn't seem to have been just randomly blown out to sea one day. We saw the same Blackbird on 9 occassions between the 15th of May and 30th of July, including being seen with  nesting material. Had we seen it on a near-daily basis we would have assumed it was resident on the island, and if we saw it less times we'd probably think it was just moving through or maybe a couple of different individuals, though Blackbirds are not recorded on Rockabill every summer. But no, this Blackbird would appear, disappear for days or weeks, and then reappear! The same Blackbird! After two summers I know the island like the back of my hand, and I'm fully sure it wasn't nesting on Rockabill - but then where was it nesting and why was it coming out to Rockabill so much? Maybe it was nesting on Lambay, the large island to our south? Or maybe on the mainland? There's very little foraging habitat on Rockabill - the island is smaller than a football pitch and mostly just bare rock, with most of the other areas covered in Common Tern nests by early June. So where was that Blackbird on the days we weren't seeing it? And was it by accident or intent that it returned to Rockabill so many times? It's a mystery!