Appearance
The smallest and most slender member of the Diver family. Head noticeably smaller than on other Divers, beak held pointing slightly upwards. In flight neck often held low, distinguishing it from similar species including the more common Black-throated Diver. Profile when swimming, appears flat-chested.
Size
Length 55–67 cm, wingspan 91–110 cm, weight 1.3–2 kg.
Nest
In a shallow depression on a mat of sphagnum moss or a sedge tussock, usually near a shoreline or even surrounded by water, enabling birds to swim right onto the nest with no need to walk. Nest made of plant material piled up in a shallow mound to raise it above the damp ground.
Breeding
2–3 eggs laid in May, incubated by both parents for 24–29 days. Young learn to fly within about six weeks. They then typically leave the pond where their nest is located in search of waters where food is more plentiful (most of the ponds where Red-throated Divers nest have no fish).
Distribution
Nests almost throughout Finland, but only beside ponds with marshy shores or pools in open bogs. Birds seek out food by visiting larger waters, often long distances from their nesting ponds. Numbers were declining until recently, but the species’ Finnish breeding population is today estimated at 900–1,100 pairs.
Migration
Leaves Finland in late autumn to winter along coasts in the Southern Baltic and Western Europe, returning April– May. The migration routes of many birds nesting in Northern Russia and Siberia pass through Finland. These migrants may be seen in May.
Diet
Small fish (Roach, Perch), crustaceans and molluscs.
Calls
Flight call a characteristic “ka-ka-ka-kaa-ka-ka”. A wide variety of moaning and howling calls may be heard around nesting ponds.
Endangerment
Protected throughout Finland and the Åland Islands.

Adult Red-throated Divers have uniformly dark brownish backs, and ash grey heads with a reddish throat patch that may be seen in good light. Their bellies are white. Their legs are black on the outer sides and pale grey on the inner sides. In their summer plumage they have dark beaks and red irises.

In winter adults have greyer upper parts with pale dots, and white underparts. They have dark grey colouring with paler broken streaks on the back of the neck and their caps. Their beaks are pale grey. Their legs are paler than in summer, but their irises remain red. Juvenile Red-throated Divers resemble adults in winter plumage, but the front and sides of their necks are grey, the colouring on their upper parts is browner, their beaks are paler, and their irises are reddish brown.

Red-throated Divers are often very noisy around the marshy ponds and pools where they nest. Their screeches and moans have even scared people. Many small woodland ponds in Finland have names referring to these noisy inhabitants.

Red-throated Diver

Taxonomy

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