Monday, 24 October 2016

CSHAS 2016: Birds on a Boat

In addition to seabirds and marine mammals, we also record the various types of terrestrial migrants which can be seen around the ship. In the height of autumn, millions (if not billions) of birds across the Northern Hemisphere are making their way south for the winter. Some species might be travelling all the way from the High Arctic to Africa while others might be making shorter journeys from Scandinavia to Britain and Ireland. Either way, most have to make water crossings at some stage and we are likely to encounter some of these in the Celtic Sea during October surveys.

Song thrush (c) Meadhbh Quinn

Easterly winds have been in place for much of the month, bringing a wide range of rare and interesting species to migration hotspots (e.g. islands and coastal headlands) along Western Europe. These winds have also guided many birds out to sea and over the past couple of weeks we’ve recorded seventeen species of migrant landbird either flying around or on the ship; collared dove, skylark, swallow, meadow pipit, white wagtail (and pied wagtail), grey wagtail, robin, song thrush, redwing, fieldfare, blackcap, chiffchaff, yellow-browed warbler, goldcrest, starling, chaffinch and goldfinch. During bright, sunny days and clear conditions, most of these birds simply fly over or around the ship, perhaps reorientating themselves before continuing on with their journey. Some rain overnight and misty conditions has resulted in several birds actually landing on the ship this morning. None have been found dead so hopefully all they require is a rest before carrying on again once the weather clears up.

Starling (c) Niall T. Keogh

A merlin was seen in flight at sea one day last week over active fishing grounds with several trawlers in operation. It would be easy to assume that they too have been blown off course or are in the midst of an active water crossing but I suspect that these falcons are out here on purpose, travelling from ship to ship in search of tired migrant songbirds to catch or using them as a platform from which to hunt storm-petrels. We have certainly witnessed them catching meadow pipits on RV Celtic Explorer before and have often found storm-petrel wing feathers here and there on the deck, looking like they were recently plucked off.

Merlin with a meadow pipit kill. Pic from October 2014 (c) William Hunt

Wildfowl and waders seen at sea are often noted as being in the throes of migration, travelling from A to B with great enthusiasm and rarely take an interest in the ship. A flock of ten European golden plover seen several miles south of Great Saltee last week looked like they were doing just that, heading for France/Iberia with intent! A couple of turnstones mixed in with a flying flock of guillemots looked somewhat more confused however!

One of our best sightings was that of a single light-bellied brent goose which crossed the bow, flying east some 19 nautical miles south-southeast of Carnsore Point. Amazing to think that this bird has just spent the summer on the breeding grounds in Arctic Canada alongside polar bears, wolves and musk ox and is now off to Ireland/Britain for the winter where it is likely to end up grazing on football pitches and golf courses at some stage!

Light-bellied brent goose (c) Niall T. Keogh

For anyone interested in checking out more records of migrant landbirds at sea then I’d suggest looking up the North Sea Bird Club website and Facebook page, the #birdsonboat hashtag on Twitter and Kevin Duffy’s pics which he often posts on Twitter from an oil rig off Shetland. 

Male blackcap (c) Niall T. Keogh

Male and female blackcap (c) Niall T. Keogh

Song thrush (c) Meadhbh Quinn

Song thrush (c) Meadhbh Quinn

Chiffchaff (c) Niall T. Keogh

Chiffchaff (c) Meadhbh Quinn

Chiffchaff (c) Meadhbh Quinn

Robin (c) Niall T. Keogh

Collared dove (c) Niall T. Keogh

Pied wagtail on the bow (c) Niall T. Keogh

Swallow (c) Niall T. Keogh

Skylark flying past the ship (c) Niall T. Keogh

Starlings (c) Niall T. Keogh

Friday, 21 October 2016

CSHAS 2016: Megafauna madness over the Celtic Deep

Day 15: Friday 21st October

Skipping ahead a bit here since the last blog update but doing so in order to share some notes and pics from an absolutely superb day spent watching an impressive abundance of 'marine megafauna' over the Celtic Deep, well to the south of Co. Wexford.

As the first rays of dawn broke, a peek out the cabin porthole revealed a flat calm sea and visibility clear to the horizon line. After a quick breakfast we were on deck and ready for action. Within minutes the seabird team picked up a small group of harbour porpoise off our port side which when radioed in to the marine mammal team was met with a reply of "we're watching more off to our starboard!". After trying (and failing) to spot some porpoises during the inshore legs of our transect lines off Cork, Waterford and Wexford over the past two weeks, we were surprised to finally encounter them this far offshore and what's more, we weren't expecting to see so many! Every time we scanned we seemed to find more and more porpoises and at one stage a single scan across the view-shed revealed no less than 58 animals! Final tallies for the day almost reached 200 animals!

Consulting with the Marine Institute fisheries scientists in the lab who were monitoring the underwater acoustic images being recorded by the ship, it was clear that there was a lot of activity going on below us with masses of plankton, krill, forage fish (herring) and even a plethora of bluefin tuna showing up! This abundance below water was certainly mirrored at the surface and in addition to the harbour porpoises we noted lots of common dolphins, racked up no less than fifteen sightings of Minke whales, two fin whales (one of which crossed right in front of the bow at close range), a single humpback whale, an Atlantic grey seal, several breaching bluefin tuna and even some blue sharks swimming at the surface (being able to see the latter is a testament to how calm the conditions were).

No doubt there was some duplication in sightings at play due to the close proximity of the parallel survey transect lines, yet the marine mammal observers in the crow's nest still amassed an impressive total of 78 sightings involving up to 500 animals!

After a ten hour day out on deck we are all a little tired and more red in the face than usual so I'll finish up and let the following selection of pics tell the rest of the story...

Ideal conditions over the Celtic Deep (c) Niall T. Keogh

Harbour porpoise (c) Niall T. Keogh

Blue shark 'knifing' at the surface (c) Niall T. Keogh

Blue shark clearly visible underwater! (c) Stephanie Levesque

Bluefin tuna (c) Niall T. Keogh

This common dolphin showed exceptionally well, actively surfacing just metres away from the ship. Closer examination of the pics suggest it may be unwell. The protruding rib-cage and sunken appearance behind the skull (known as a 'post-nuchal depression') indicate that it is in poor body condition (c) Niall T. Keogh

A couple of perfectly healthy looking common dolphins (c) Meadhbh Quinn

Minke whale showing the typical, falcate (sickle shaped) dorsal fin (c) Gary Kett

Minke whale showing a straighter, more erect shape to the dorsal fin (c) Meadhbh Quinn

This humpback whale spent quite some time logging (resting) at the surface (c) Meadhbh Quinn

But after a while the humpback eventually treated us to a nice tail-fluke! (c) Meadhbh Quinn

Fin whale surfacing sequence (c) Meadhbh Quinn / Niall T. Keogh

Irish Whale and Dolphin Group marine mammal observers: Meadhbh Quinn and Gary Kett

Marine and Freshwater Research Centre GMIT seabird observers: Stephanie Levesque and Niall Keogh

Celtic Sea sunset (c) Gary Kett

Monday, 17 October 2016

CSHAS Days 5 to 10: Sunny Southeast and the Celtic Deep

Day 5 to 10 sightings: Tuesday 11th to Sunday 16th October

We have been playing a game of cat and mouse with some of the largest animals in the ocean over the past week… the whales are currently winning out!

While enjoying excellent weather off Cork during the first few days of the survey, both fin and humpback whales were being seen from headlands in West Waterford (many thanks to Andrew Malcolm for the updates!) but by the time we reached this area the weather had deteriorated to the point such that no large whales were spotted. 

High pressure conditions with easterly winds allow for fantastic visibility and a stunning mix of colours at sunrise and sunset (c) Usna Keating

Similarly, while enjoying the gannet spectacle over the Celtic Deep, our fellow seabird and cetacean surveyors on RV Cefas Endeavour (taking part in the Peltic Survey) encountered up to 12 fin whales on their transect lines just east of us! We saw two Minke whales ourselves that day and as delightful as they are, we were somewhat dismayed to learn that their larger cousins eluded us once again.

The next day, while making our way north along a transect line towards the Saltee islands off Co. Wexford, excellent sea conditions and visibility allowed us to spot two sets of large baleen whale blows several kilometres off which most likely came from fin whales due to the tall and narrow nature of the blows. Another large baleen whale blow was then recorded over the Celtic Deep well to the northwest of Cornwall but the animals body (and thus identity) remained hidden by heavy swell. Slow progress! 

Rainbow over Great Saltee (c) Niall T. Keogh

Common dolphins have thankfully remained abundant, ensuring Meadhbh has been busy racking up the sightings from the crow’s nest. Mostly small groups noted but one sighting of 60+ animals bounding towards the ship with great enthusiasm in rough seas made for quite the sight. A small group of bottlenose dolphins seen on the inshore section of a transect line to the east of Cork Harbour were too distant to get usable dorsal fin pics for photo-ID purposes but it is likely that they are from the 'coastal' group, one of three populations known to occur in Irish waters. We’ve also had a sighting of unidentified dolphins over the Celtic Deep which were most likely bottlenose again.

Common dolphins (c) Niall T. Keogh

Bluefin tuna and Portuguese man o’ war continue to be seen here and there; attempts at capturing breaching tuna on camera are slowly but surely getting better…

Breaching bluefin tuna (c) Niall T. Keogh

A couple of stowaways were also reported to us by the crew! Recently fledged juvenile European storm-petrels out at sea for the first time can become disorientated during rough weather, get attracted to the lights of ships, land on the deck and then find it difficult to get airborne again. Two such birds were found nestled in the corners of the deck and whilst initially looking a little bedraggled and waterlogged, were allowed some time to rest and dry off in our special ‘stormy hotel’ (a box!) before being released safely overboard the following morning. With any luck they will survive and live long and healthy lives (some storm-petrels are known to reach 30 years old!).

Juvenile European storm-petrel (c) Niall T. Keogh

The seabird list for the trip now stands at 25 species after cormorant, grey phalarope, black-headed gull and little gull were added over the past few days. Guillemots and gannets remain by far our most abundant species recorded each day whilst plenty of interest is being added by good numbers of great skuas, yet more yellow-legged gulls (survey tally now at seven birds), occasional sooty shearwaters, puffins, Arctic skuas, small flocks of European storm-petrels, a single Balearic shearwater east of Hook Head and fantastic views of great shearwaters following the ship while some 35 nautical miles northwest of St Ives, Cornwall.

Two grey phalaropes seen just a few miles off Helvick Head (c) Niall T. Keogh

Great shearwaters (c) Niall T. Keogh

Sooty shearwater (c) Niall T. Keogh

Most great skuas seen in the Celtic Sea at this time of year are in the midst of active wing moult (c) Niall T. Keogh

Smaller numbers of pristine juvenile great skuas have also been noted (c) Niall T. Keogh

Adult yellow-legged gull following the ship over the Celtic Deep (c) Niall T. Keogh

1st calendar-year yellow-legged gull (c) Niall T. Keogh

Arrivals of migrant landbirds continued throughout with more meadow pipits, alba wagtails, swallows, redwings and chiffchaffs noted plus additions of skylark, song thrush, starling and even a tiny goldcrest (arguably one of the world’s greatest migrants… a wee bird capable of making almost 1,500km long journeys in just 20 days, across open water and weighing in at just 5 grams!).

Song thrush on RV Celtic Explorer (c) Niall T. Keogh

Chiffchaff on RV Celtic Explorer (c) Niall T. Keogh