We boarded the CLdN freight ferry Power late on Monday night and went straight to our cabins to get a bit of sleep before an early start to a long day of surveying on the Tuesday.  With the survey being close to midsummer and its short nights we were keen to max out on the available daylight suitable for surveying.

At 05.30 we were escorted up to the spacious bridge where we established ourselves on the starboard wing where we had plenty of room to carry out our survey without getting in the way of the crew.  This position has access to all the ship’s instruments that we needed to get the measurements for position, course, and windspeed, and we also had permission to use the bridge’s coffee machine to keep us going and to chairs that we needed later in the day!

Conditions were ideal for surveying with good weather and visibility, with the sea state varying between 1 and 3.  The ship provided a very stable and comfortable platform for carrying out our survey and the height of the bridge gave us a view to the horizon about 30km away!

Bird activity was pretty brisk for the first survey stage with all the expected species on show.  There were good numbers of Gannet and Manx Shearwater skimming low over the waves, while several Fulmar were also recorded.  There was also plenty of auk activity including a number of Puffin, mainly spotted by their bright orange legs, as well as several Guillemot parents with attendant juveniles.  Rob thought the frequent sightings of Great Black-backed Gull were somewhat out of the ordinary, and we wondered whether these large predatory gulls were looking for an easy meal of young flightless Guillemot!

Just as we were about to conclude the first leg of the survey at the two lighthouses at the entrance to Dublin Port, two very white terns flew close to the bridge windows.  Rob was immediately on to these, and seeing they had black beaks, muttered ‘they have got to be Roseate Tern!  He took a few hasty snaps through the window as the birds flew to join other terns feeding out in the bay.  The photos, though not good enough to win Wildlife Photographer of the Year, do show indeed features of Roseate Tern – black beak with a hint of rose at the base, and dark leading edges to the wings (just like Rob had mentioned to us on the MARINElife training day a couple of week ago in Durham!)
Roseate Tern in Dublin Bay (photo: Rob Petley-Jones)
Rob has since made some investigation into the presence of Roseate Tern in Dublin Port and has found out that five pairs of these extremely rare birds have indeed taken up residence and are nesting on one of the new tern islands provided by the Dublin Port Authority and Bird Watch Ireland.  The tern islands are specially designed for Roseate Terns with covered nesting sites which the birds prefer.  Good for Dublin Port Authority and Bird Watch Ireland, and lucky us to have recorded these gorgeous birds!

Follow this link for more information on the Dublin Roseate Tern success:   https://birdwatchireland.ie/roseate-terns-nest-in-dublin-port-for-the-first-time/

The first stage of the survey lasted until nearly 10.00 when we arrived in Dublin, where we had a three-hour break while the vessel unloaded and reloaded its cargo of container wagons.  This gave us a chance for some welcome lunch and a bit of a fresh air on the passenger deck to have a look around Dublin harbour and practice our gull identification.  A single Grey Seal watched us for a few minutes before heading off to see what the other vessels were up to, while a number of Black Guillemot buzzed busily around the brown waters of the River Liffy.

As we sailed out of Dublin Port on the second leg of the survey, Cormorant and Shag were active, and I was able to increase my confidence in differentiating Black-headed Gull and Mediterranean Gull as they flew about the ship.

Bird activity was again brisk for the first couple of hours of the return leg of the survey, with plenty of feeding activity from diving Gannet and splashing Common/Arctic Tern, Manx Shearwater, and Kittiwake.  These feeding flocks give us the first of our five spectacular cetacean encounters with several Common Dolphin seen feeding with the birds.  A group of four Common Scoter also scooted past, unusual for the summer season.

The other cetacean encounters were all fairly late in the crossing as we approached the wind farms off the Cumbrian and Lancashire coasts, usually after we were alerted by unusual accumulations of feeding Gannet and Kittiwake.  This made us alert to the splashing and leaping Common Dolphin, and to the several small calves swimming with their parents!  The best encounter was with a pod of at least 45 Common Dolphin, which leapt and rode the bow wave of the Power for a number of minutes before disappearing in the wake of the ship, still leaping and splashing!  My rather poor photo does not do the sighting any justice, but I was just pleased to get a picture that was not just of empty sea!
Common Dolphin pod approaching CLdN Power (photo: Allison Gleadhill)
The last cetacean encounter was of several large grey dolphins that were not nearly as acrobatic as the dolphin we had been watching earlier, and Rob concluded that these were probably Bottlenose Dolphin, being very close to where he had seen a similar group in June, although I would not have been confident enough to commit to anything other than that these were dolphins!

It was surprising that no Harbour Porpoise were recorded on this survey, despite the sea state conditions being reasonably favourable to allow sightings of these fairly elusive cetaceans.

We stopped surveying around 20.00 after a very long day of sea watching, and the excellent steward kindly rustled us up a most welcome omelette to fuel us for the drive back home after our survey.  Our thanks to Captain Jaak Kalm and his friendly crew for their accommodation of us during this survey, and to CLdN for their continue valuable support of the MARINElife Irish Sea survey programme.

Allison Gleadhill and Rob Petley-Jones, Research Surveyors for MARINElife

Registered Charity No. 1110884; Registered Company No. 5057367

Summary of Weather and Species Recorded

 Weather

Outward leg:   Wind W F2-3; Sea state 2-3; Visibility clear and bright

Inward leg:       Wind W F3-2; Sea state 2-3; Visibility clear and bright