14 Apr 18 - Atlantic Odyssey - Day Sixteen: At Sea From Tristan Da Cunha To St Helena

Today was the first of four full days at sea between Tristan da Cunha & St Helena. It was an ominous start to the day looking at the weather. Fortunately, the weather picked up during the day.

Early morning view from the Plancius

We were now at the start of the warmer tropical waters. At dawn, the sea temperature was 22 degrees which compared with 20 degrees at Tristan da Cunha, 16 degrees at Gough Island, 12 degrees for the two days before Gough Island and a mere 3 degrees around South Georgia & for the first two days after leaving South Georgia. The warmer waters & being back in deep ocean meant we were destined to see low numbers of Seabirds during the day. My personal counts were a single Yellow-nosed Albatross, 2 Sooty Albatrosses, 8+ Great-winged Petrels, 15+ Soft-plumaged Petrels, 15+ Spectacled Petrels & a lone Storm-petrel sp. It was the last day I was to see most of these species with only a couple of Great-winged Petrels & Spectacled Petrels lasting for a final day.

Soft-plumaged Petrel: The last day I was to see any of these great Pterodromas

Spectacled Petrel: I only saw two more on the following day

As well as the last of the cold Southern ocean Seabirds, we saw the first Cory's Shearwater cross the bows in the late afternoon. It was the only one we saw until we left St Helena & started heading for Ascension Island, so was well away from the main Cory's Shearwater waters.

Cory's Sheawater: The extend of black in the wing tip makes this a Cory's Shearwater. There is a lot less white in the outer primaries of Scopoli's Shearwaters. I will come back to the separation of these two subspecies later in one of the future Odyssey Posts

Although we didn't see any Cetaceans during the day, we did manage to see a Blue Shark, as well as, another Shark sp.

Blue Shark: It was probably only 20 metres off the side of the Plancius

Blue Shark: I saw a few Sharks during the trip, but few could be identified. Generally, all I saw was a dorsal or tail fin breaking the surface & on several occasions these were also at some distance in front of the Plancius & they had disappeared underwater before we got closer. However, we did manage to identify some of the Sharks seen & I'll come back to them in a later Post

7 Apr 18 - Atlantic Odyssey - Day Ten: At Sea From South Georgia To Gough Island

The previous day I had been mainly Birding from a cosy chair by the window in the observation lounge, as rough seas had stopped us from going out on deck. This allowed me to see my first Great-winged Petrels & Atlantic Petrels, with a few Spectacled Petrels from the deck when we were allowed out again in the late afternoon when the seas moderated. The observation lounge was fairly reasonable for looking at the sea & had the benefits of being warm & dry with easy access to the drinks machine. However, it wasn't any good for Bird photography. So it was good to wake up to find the seas had moderated & we had free access to the decks again & I could get the camera out again.

Sooty Albatross: Adult. It was good to get the opportunity for some better photos

Sooty Albatross: Adult

Sooty Albatross: Adult. Sooty Albatrosses are very elegant in flight

Sooty Albatross: Subadult. The pale collar & scruffy mantle indicates this is a subadult. Both species can have a pale collar, however, subadult Light-mantled Sooty Albatrosses would also have the pale colouration extending onto the belly & Sooty Albatrosses will have a predominately dark mantle. Therefore, this is a subadult Sooty Albatross

Sooty Albatross: Subadult. Another view of the same individual

Wandering Albatross: The plumages of Tristan Wandering Albatrosses & Snowy Wandering Albatrosses overlap & therefore it is not possible to be sure which subspecies this is

Wandering Albatross: Apparently, Tristan Wandering Albatrosses are smaller & slighter than Snowy Albatross, but I'm struggling to see this in my photos. The location is the best way to separate the two subspecies, but given the Plancius was roughly halfway between the two populations, I don't think this individual can be assigned to a particular subspecies

Kerguelen Petrel

Spectacled Petrel: Spectacled Petrels only breed on inaccessible Island in the Tristan da Cunha group

Great Shearwater

Great Shearwater

Brown Skua: Falklands Brown Skua. The dark colouration confirms this is a Falklands Brown Skua, rather than the first Tristan Brown Skua of the trip

When we were at sea, there were generally a couple of lectures a day from members of the Expedition staff. However, we also had a superb guest lecture from Bob Flood who was one of the passengers, on the identification of Black-bellied Storm-petrel & White-bellied Storm-petrel in the Atlantic. This isn't as simple as checking the belly colour as some populations of Black-bellied Storm-petrels have white-bellies. Simplistically, the Southern population of Black-bellied Storm-petrels are most likely to have black-bellies, whereas the populations that breed further North in the South Atlantic are more likely to have white-bellies. Bob said there are other populations in the Pacific with streaky bellies, but they were not covered within the lecture. I will come back to this subject in a later Post.

'Black-bellied' Black-bellied Storm-petrel: This individual clearly has a black central belly stripe

'White-bellied' Black-bellied Storm-petrel: This individual clearly has a white-belly, but is a Black-bellied Storm-petrel

'White-bellied' Black-bellied Storm-petrel: Another photo of the same individual

Black-bellied Storm-petrel: Not all Black-bellied Storm-petrels can be identified to a subspecies

There had been up to three Cattle Egrets around the Plancius since the previous day. They generally were hanging around on the relatively quiet zodiac deck, but every now & then, somebody managed to disturb them & force them to fly around again. I suspect some of the photographers were keener to get photos, than necessary thinking about the best interests of the Cattle Egrets. My photos were all taken when they appeared in front of me as I didn't think it was right to go looking for them on the back deck & risk disturbing them.

Cattle Egret: This individual has been disturbed again

Cattle Egret: Trying to look camouflaged on the front deck

Eventually, they were seen flying off the following day when we were still a couple of days from Gough Island. At least, one was seen dropping into the ocean before it got out of sight. I guess it hadn't eaten for several days & was probably exhausted. It sounds harsh, but perhaps that was the better option than for these Cattle Egrets to reach Gough Island. Once there they might become another predator on the Seabirds on Gough Island. Cattle Egrets have a world wide range & have rapidly colonised South America in recent decades. It is not clear if these individuals had originated in South America or Africa or were perhaps from South Georgia, as we had seen one or two there. They are a relatively recent arrival to South Georgia. There have generally been a few Cattle Egrets seen on each of the recent Odyssey voyages, therefore their range expansion still seems to be continuing.