Great Northern Diver (Gavia immer) Information
Great Northern Diver is one of the Largest and generally least numerous of the three divers. Size often confusing at sea, but large, angular head and heavy bill distinguish at all seasons. In summer, black head and neck, broken only by a narrow oval of strips on the neck. Chequered back pattern more clear-cut than Black-throated. In winter, darker above than Red-throated, but scaly back pattern produces a paler effect than Black-throated. In great northern diver, the dark crown does not enclose eye. In-flight, wingbeats slower than the smaller divers.
Status: Great Northern diver has bred and regularly summers in northern Scotland. Winter visitor to most coasts; more regular in north and west.
Similar Species: Angular crown and mottled upperparts distinguish great northern diver from winter Black-throated diver.
Great Northern Divers Facts (Size and Habitat)
| Type | duck-like, goose-like |
| Size | 69-81 cm (30 in.) |
| Habitat | freshwater, sea |
| behaviour | swims, dives from surface, takes off and lands on water |
| Flocking | summer solitary; small flocks winter |
| Flight | strong and powerful; direct |
| Voice | summer – loud wails, cackling laugh; winter – occasional croaks, moans |
Bird Identification
| Ad.summer | |
| Crown | black |
| Upperparts | balck and white, two chequered ovals |
| Rump | black |
| Tail | black; short and pointed |
| Throat | black |
| Breast | white |
| Belly | white |
| Bill | black; straight and pointed |
| Legs | black; short |
| Ad.winter | brown above, white below |
| Juvenile | as Ad.winter, speckly black |
Great Northern Diver Breeding
| Nest | scrape at water’s edge |
| Eggs | 2; olive-brown, blackish spots |
| Incubation | 29-30 days |
| Young | active downy |
| Fledging | 12 weeks |
| Broods | 1, May-September |
| Food | fish, amphibians |
| Population | 3500+ winter |