Pacific Diver (Gavia pacifica)

OTHER NAMES: Pacific Loon
Latin Etymology: Gavia (name in Latin for an unidentified seabird) pacifica ("of the Pacific")

 
Non-breeding Pacific Diver (Gavia pacifica) at Big Sur, California - September 2022

Featured Subspecies: N/A
Weight: 1-2.5kg  /  Length: 58-74cm  /  Wingspan: 110-128cm
NO UK STATUS / IUCN Red List: Least Concern

The Pacific Diver as it's name suggests is a bird whose range is centred on the North of the Pacific, with its breeding range in Siberia, Alaska and Canada, although it does breed as far East as Hudson Bay and Baffin Island, which would be presumaby the source of the rare vagrancies to Europe. As with most divers, their breeding plumage includes some spectacular pinstripe patterning, but as with other species their High North breeding range makes seeing them in their drab Winter plumage far easier, where they can be distinguished from other species by the presence of a narrow chin strap.

Related Species:
ORDER: Gaviiformes
FAMILY: Gaviidae
GENUS: Gavia
SUBSPECIES: none - monotypic 

 - Sighting Locations -

UNITED STATES 
Breeds in Alaska, Winters along West Coast
 - CALIFORNIA 2022 TRIP: Seen at Big Sur

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Red-throated Diver (Gavia stellata)

OTHER NAMES: Red-throated Loon

Latin Etymology: Gavia (name in Latin for an unidentified seabird) stellata ("set with stars")

Breeding plumage adult Red-throated Diver (Gavia stellata) at Bridlington, Yorkshire - September 2023

Featured Subspecies: N/A
Weight: 1-2.7kg  /  Length: 53-69cm  /  Wingspan: 110cm
UK AMBER LIST / IUCN Red List - Least Concern

Allegedly the most common diver species in the UK, found breeding in Northern Scotland, and Wintering along the entire coast. In theory it should have been the easiest diver for me to see, however I didn't find this to be the case.  The problem has for me been that it tends to spend it's time fairly far out at sea where it is difficult to observe and it's breeding grounds are in the more remote parts of the UK, there were a few occasions where very distant birds flying out at sea may have been this species but were just too far off to get a clear identification.  However, I eventually struck lucky with an individual who I came across by chance feeding just off a beach in Cornwall.

 - Related Species -
ORDER: Gaviiformes
FAMILY: Gaviidae
GENUS: Gavia
SUBSPECIES:  None - monotypic

 - Sighting Locations -

UNITED KINGDOM - Scarce Breeding Species (1000-1600 pairs) and Uncommon but Local Migrant (approx. 17,000 birds)

 - Wintering bird seen at Trevose Head (1 Winter plumage adult in 2014), numerous birds seen off Bridlington in September 2023.

Further Notes: BirdForum Opus, IUCN Red List RSPB, Wikipedia, Xeno-canto .

Black-throated Diver (Gavia arctica)

OTHER NAMES: Arctic Loon, Black-throated Loon

Latin Etymology: Gavia (name in Latin for an unidentified seabird) arctica ("Arctic")

Winter plumage adult Black-throated Diver (subspecies G. a. arctica) at Swithland Reservoir, Leicestershire - January 2014

Featured Subspecies: Gavia arctica arctica

Weight: 2-3.2kg  /  Length: 68-73cm  /  Wingspan: 120cm

UK AMBER LIST / LEAST CONCERN - IUCN Red List

Also known as the Arctic Loon and the Black-throated Loon.  Theoretically at least, the black-throated diver is the rarest of the three divers found regularly in the UK, but as I've found the theoretical easiest to track down the hardest to find (the red-throated) I wouldn't read too deeply into that information.  The divers generally seem to be fairly frustrating to get hold of unless you have the fortune to live in the places they turn up; generally along the coast or at certain reservoirs - trying to make one off trips to catch up with them often results in them not being found when you get there.  The black-throated diver itself is intermediate between the great northern and red-throated - the Summer plumage of any should be fairly easy to differentiate but in the Winter plumage, the beak is probably the best quick diagnostic to go from - the Great Northern has the sword like proportions of heron bill, the black-throated is more slender and like a grebe and the Red-throated has a distinct upwards turn to it.

 - Related Species -
ORDER: Gaviiformes
FAMILY: Gaviidae
GENUS: Gavia
SUBSPECIES: G. a. arctica, G. a. pacifica, G. a. viridigularis

 - Sighting Locations -

UNITED KINGDOM - Scarce Breeding Species (190-250 pairs) and Scarce Winter Migrant (approx. 560 birds)

 - Vagrant bird seen at Swithland Reservoir (1 Winter plumage adult in 2014) .

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Great Northern Diver (Gavia immer)

OTHER NAMES: Common Loon, Great Northern Loon

Latin Etymology: Gavia (name in Latin for an unidentified seabird) immer (Norwegian name for species)

Two adult breeding plumage Great Northern Diver at Teslin Lake, Yukon, Canada - August 2024

Featured Subspecies: N/A
Weight: 4.1kg  /  Length: 65-91cm  /  Wingspan: 137cm
UK AMBER LIST / IUCN Red List: Least Concern

The Divers, and Great Northern Diver in particular have long been a bit of a bugbear for me, I've looked for them on several occasions in places they've supposed to be and it wasn't until I wasn't looking for one that I happened to stumble across it!  The Great Northern is the largest of the three regular divers to frequent our waters but also the only one that doesn't breed.  They are roughly cormorant sized and shaped but are stockier with long dagger like beaks.  They do as the name suggest, spend a lot of time underwater hunting for fish meaning they can, as this one did, just vanish into nowhere despite being on a flat lake with nowhere to hide.

- Related Species -
ORDER: Gaviiformes
FAMILY: Gaviidae
GENUS: Gavia
SUBSPECIES: None - monotypic

 - Sighting Locations -

CANADA - Breeds over most of the Country except Arctic and Great Plains
  - CHICAGO TO ALASKA ROADTRIP 2024: - Seen in Yukon

UNITED KINGDOM - Scarce Winter Migrant (approx. 2600 birds)

 - Wintering bird seen on Queen Mother Reservoir (1 Winter plumage adult in 2012).  Seen off Cornwall.

UNITED STATES - Breeds on Northern Border, Winters along nearly entire Coast
 - CHICAGO TO ALASKA ROADTRIP 2024: Seen in Alaska

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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