Great Cormorant

Glossy blue-black plumage with metallic sheen. Distinctive white thigh patch and white feathers on throat and cheeks. Fine white filoplumes present on the hindneck and crown.

Duller, more brownish-black plumage lacking the white thigh patch and the white filoplumes on the head. The throat usually remains pale.

Upperparts dark brown, underparts variable ranging from dirty white to light brown mottling. The throat is pale, and the plumage appears overall duller and less contrasted than in adults.

Minimal; males are on average slightly larger and heavier than females, but the plumage coloration is identical.

Large, dark waterbird with a powerful bill hooked at the tip. Characteristic upright perching posture, often with wings spread to dry the plumage. Yellow gular skin at the base of the bill.

European Shag (Phalacrocorax aristotelis) - smaller, thinner bill, possesses a small crest in breeding plumage; Pygmy Cormorant (Microcarbo pygmaeus) - significantly smaller with a shorter bill.

Robust, grey to blackish, with a distinct downward hook at the tip. The base of the lower mandible features a patch of bare, yellow to orange skin.

No true song; various guttural vocalizations within the colonies.

Deep, harsh, croaking sounds like 'rrow-rrow' or 'kraw', primarily heard at the nest or within the colony.

Nearly cosmopolitan distribution; in Europe primarily along coasts (P. c. carbo) and inland waters (P. c. sinensis). Large parts of Eurasia, Africa, and Australia.

Partial migrants; European populations winter at ice-free water bodies in Central and Southern Europe as well as the Mediterranean region.

In Central Europe predominantly short-distance or partial migrants; birds from Northeastern Europe migrate southwest.

Colonial breeder on coastal cliffs (Atlantic race) or in tall trees near fish-rich inland waters, lakes, and large rivers (continental race).

Large inland lakes, rivers, estuaries, and shallow coastal waters. Prefers water bodies with high fish density and sufficient perching sites.

Large platform made of sticks and twigs, often lined with reeds or grass. Nests and trees are often stained white by droppings (guano), which can eventually kill the trees.

Elongated-oval, pale blue to greenish, usually covered with a thick, chalky-white layer.

Both parents incubate and feed the young by regurgitating pre-digested fish.

Exclusively fish-eating (piscivorous). The spectrum includes species such as roach, perch, bream, or eels, depending on availability.

Similar to the breeding season; opportunistic hunting of locally abundant fish species in ice-free waters.

Pursuit diving; chases fish underwater by actively swimming with its feet. Can dive to depths of up to 9 meters.

Visual hunter; actively searches for fish schools or individual prey. Often engages in social fishing in groups.

Highly social; breeds in colonies, roosts in groups, and often forages communally.

Often flies in V-formation or lines. Forms large communal roosts at traditional resting sites.

Human persecution (fishery conflicts), destruction of breeding colonies, entanglement in fishing nets, environmental toxins.

After a strong increase in the late 20th century, the population in many parts of Central Europe is now stable or slightly declining.

Protection of breeding colonies and roosting trees. Management plans to resolve conflicts with inland fisheries (regional cormorant ordinances).