The Cormorant (family Phalacrocoracidae) is a group of medium to large aquatic seabirds and waterbirds adapted for diving.

Cormorants are streamlined divers with dark plumage and long necks. Adults of common species typically measure about 70–100 cm in length with wingspans of roughly 100–160 cm, though size varies across species. Body mass generally ranges from 1–3.5 kg depending on species and sex.

Plumage is usually black or dark brown; some species show white throat or cheek patches during breeding. The bill is hooked for catching fish, and the feet are webbed for propulsion underwater. After diving, cormorants are often seen with wings spread to dry, as their feathers are less water-repellent than those of many seabirds.

Vocalisations are generally guttural croaks and grunts, especially at colonies.

Egg Description:
Cormorant eggs are typically pale blue, greenish or chalky white, sometimes with a thin calcareous coating. They often become stained brown from contact with nest material and guano during incubation. The shell is moderately robust. Clutches usually contain 3–4 eggs, though numbers vary by species.

Location:
Species in the family Phalacrocoracidae breed in diverse aquatic habitats: sea cliffs and rocky islands, coastal trees or mangroves, lakesides and riverine sites. Distribution is nearly global, absent only from the coldest polar regions. Outside breeding, many species disperse widely to coastal or inland waters where fish are abundant.

Average Size (Adult Bird – general range):
Length: ~70–100 cm (varies by species).
Wingspan: ~100–160 cm.
Weight: ~1–3.5 kg.

Family:
Phalacrocoracidae

Ecological Role:
Cormorants are specialised fish-eaters, diving underwater to pursue prey. They help regulate fish populations and act as indicators of aquatic ecosystem health. Large colonies contribute nutrient input to surrounding environments through guano deposition.

Movement and Behaviour:
Many species are migratory or partially migratory, moving to warmer or more productive waters outside the breeding season. Cormorants are social during breeding, often nesting in colonies on trees, cliffs or islets. Nests are constructed from sticks, seaweed and other vegetation.

Reproduction & Eggs:
Nests vary by species but commonly consist of stick platforms or seaweed mounds. A typical clutch contains 3–4 eggs. Incubation lasts about 27–31 days and is shared by both parents. Chicks are down-covered and dependent on adults for feeding; they fledge after several weeks but may remain near the nest while learning to forage.

Conservation Status:
Most cormorant species are assessed as Least Concern, though local populations may fluctuate due to changes in fish availability, habitat disturbance and human management where birds are perceived to compete with fisheries.