MARINElife Survey Report, Felixstowe to Vlaardingen, “Suecia Seaways” 3rd May 2016

Fraser Paterson and Jamie Smith, Research Surveyors for MARINElife

Summary of Weather and Species Recorded

Weather
Outward - bright, good visibility: light north westerly-north winds but strong glare from the sun.
Return -bright, good visibility with glare in the afternoon: light to moderate west-north westerly winds.

Marine Mammals
(Possible) Minke Whale Balaenoptera acutorostrata 1
Harbour Porpoise Phocoena phocoena 1
Grey Seal Halichoerus grypus 2
Seal sp. 1

Seabirds
Gannet   Morus bassanus 22
Fulmar Fulmarus glacialis 4
Cormorant Phalacrocorax carbo 6
Great Skua Stercorarius skua 1
Great Black-backed Gull Larus marinus 2
Lesser Black-backed Gull Larus fuscus 142
Herring Gull Larus argentatus 109
Kittiwake Rissa tridactyla 92
Black-headed Gull Larus ridibundus 15
Common Gull Larus canus 3
Sandwich Tern Sterna sandvicensis 35
Common Tern Sterna hirundo 124
'Commic' Tern Sterna hirundo/paradisaea 24
Guillemot Uria aalge 2

Terrestrial Birds
Swallow Hirundo rustica 4
Wren Troglodytes troglodytes 1

We made our way up to the bridge at 04:45 am and commenced the survey just before sunrise.  The ship had left Felixstowe three and a half hours earlier and had not yet reached the regular 'hotspot' north of the Gabbards wind farm area.  Initially, we encountered several small parties of adult Kittewake, a group of 'Commic' Tern and an adult Gannet all flying eastwards.  The first surprise of the day was the appearance of a 'little brown job' in front of the bridge which quickly dived down amongst the vehicle trailers.  We initially thought it could have been a Goldcrest, but when it showed itself a little later it allowed us to identify it as a Wren.  Two pairs of Swallow were the only other terrestrial migrants.

Grey Seal Rick Morris 01

Grey Seal (PHOTO: Rick Morris, August 2012)

As we travelled east towards the rising sun, we observed further groups of Commic, Common and Sandwich Tern interspersed with, mainly juvenile, Lesser Black-backed Gull and adult Gannet.  A possible seal was seen fleetingly but there was a distinct 2-hour lull in observations in the middle of the route. Progressively worsening glare from the sun on the waves limited our ability to spot birds. Identifying what we did see from silhouettes was challenging to say the least, unless they flew down the starboard side of the ship.

Numbers of gulls and terns picked up again closer to the Dutch coast where the fresh water from the river extended into the sea; especially along the clearly visible mixing zone.  Here, we spotted a Grey Seal that swam down the starboard side of the vessel and, immediately afterwards, there was the typical single roll of a Harbour Porpoise as it moved away from the ship.

As we entered the channel, we decided to concentrate on the birds in the water and along the right-hand bank of the river on the inward leg and then focus on the other side on our return. We observed good numbers of Cormorant, Lesser Black-backed and Herring Gull interspersed with smaller numbers of terns. Some Black-headed Gull were in flight over the river with many more gulls nesting or roosting outside our recording area. Sailing up-river towards Rotterdam, we also recorded Mute Swan, Gadwall, Mallard, Shelduck, Coot, Common and a few Sandwich Tern with occasional flyovers by Swallow, Sand Martin, Egyptian Geese plus the ubiquitous corvids, Feral Pigeon and Greylag Geese. Oystercatcher was the only wader we observed and a distant Kingfisher flitted across one of the pools behind the levee. We stopped recording just before the ship turned into the DFDS area but remained quietly on the bridge to watch the crew expertly manoeuvre the vessel onto its berth.

After a superb lunch and a deserved 'power nap', we reclaimed our position on the bridge and watched 40 or so Common Tern dive into the water as the vessel moved out into the river.  The outward leg to the sea produced more of the same species, although a male Black Redstart was observed flying in front of a warehouse.

As the ship's return route is to the north of the path we took arriving, we passed quickly through the mixing zone accompanied by a single Greater Black-backed Gull, several Lesser Black-backed Gull and groups of terns heading out to sea.  Another Grey Seal was observed close to the mixing zone.

Unfortunately, although the sea state had improved much since our arrival, much of the return journey to Felixstowe was marred by strong glare.  We observed silhouettes of gulls and tern species alongside more easily identifiable Gannet, with Kittiwake reappearing later on.   The glare caused difficulty identifying a bird that flew just above the water and right under the bridge. We noted that the plumage seemed unusual but it was not oil-stained but could not identity it until it flew out of the glare. It was the first of several Fulmar, probably in partial moult that were struggling to find any lift in the light winds.

Great Skua Peter Howlett 04

Great Skua (PHOTO: Peter Howlett, July 2015)

We sailed past a few fishing vessels that were surrounded by scores of birds, however they were too distant to count in the conditions; though we could pick out a few individual birds like Fulmar and Kittiwake.  A distinctive Great Skua - the bird of the day - was seen rising from the water and flying towards the 'party' but the ship kept sailing and we did not manage to see it in action.  Typically, as we entered an area with cloud cover, the loss of glare was accompanied by another lull in sightings. A pair of Guillemot flew across the bows shortly before we called a halt to the survey after the sun had set.

Once again, our sincere thanks go to Captain Jan Bruun, the officers and crew of the Suecia Seaways, for their kind hospitality and interest in our work which made for a very enjoyable crossing.

Fraser Paterson and Jamie Smith, Research Surveyors for MARINElife