What is the black bird that dives in the water?

The black bird that is known for diving in water is likely the cormorant. Cormorants are medium-sized waterbirds that have predominantly black plumage and long necks. They are expert swimmers and can dive deep underwater in search of fish and other prey. Cormorants are found near lakes, rivers, coasts and wetlands around the world. When swimming, their bodies are low in the water with just their long necks and heads visible. Upon surfacing from a dive, cormorants often perch on rocks or tree branches and hold their wings outstretched to dry. There are about 40 different species of cormorants, some of which also have white or colored patches on their plumage. They range in size from about 2-4 feet in length. Some key identifying features of cormorants include:

• All black or very dark plumage
• Long, thin neck
• Hooked bill
• Webbed feet
• Slim, streamlined body profile
• Ability to dive and swim underwater

So in summary, the black waterbird best known for its diving behavior is the cormorant. When you see a dark, slender swimming bird that suddenly disappears below the surface and reemerges later, it is likely a cormorant coming up from a fishing dive.

Cormorant Species and Geographical Distribution

There are around 40 recognized species of cormorants and shags. They are distributed widely across marine and freshwater habitats around the world. Some of the major cormorant species include:

• Great Cormorant – Found throughout Europe, Asia, Africa, and Australia. One of the largest species at over 3 feet long.
• Double-crested Cormorant – Common in North America with a distinctive small double crest on the head.
• Pelagic Cormorant – Found along the Pacific coast of North America. Has a small throat pouch.
• Red-faced Cormorant – Named for its red facial skin, it lives in the Aleutian Islands and coastal Alaska.
• Imperial Shag – Blue-eyed shag found along the coast of southern South America.
• Pied Cormorant – Black and white cormorant found in eastern and southern Africa.
• Little Pied Cormorant – Smaller black and white cormorant of Australia and Asia.
• Guanay Cormorant – Coastal Peru and Chile. Guano or bird droppings were once mined from its guano-rich breeding islands.

Cormorants occupy an impressive diversity of habitats on every continent except Antarctica. They can be found in:

• Coastal areas – rocky cliffs, beaches, estuine waters
• Inland lakes, rivers, deltas
• Lowland wetlands and swamps
• Mountain streams and alpine lakes

Some species have adapted to man-made habitats like reservoirs, aquaculture ponds, sewage lagoons, and more. Cormorants thrive in areas with abundant small fish to prey on.

Physical Description

Cormorants are medium-sized water birds with a slender, streamlined appearance suited for swimming and diving. Some key physical characteristics include:

• Size – Most species 2-3.5 feet (60-100 cm) long with a 3-5 foot (1-1.5 m) wingspan.
• Weight – 1.5-5 lbs (0.7-2.3 kg) depending on species.
• Plumage – Predominantly black or very dark colored. Some white patches in certain species.
• Long, thin neck – Allows them to reach down to capture prey while swimming at the surface.
• Hooked bill – Helps grasp slippery fish.
• Webbed feet – Powerful feet for diving and propelling through water.
• Short legs set far back on the body.
• Compact, streamlined body shape.

Male and female cormorants look alike. Their dark plumage is owing to melanin pigments and is an adaptation for swimming underwater. The feathers are not completely waterproof, allowing the birds to dive more efficiently. However, this means they must spend time air-drying their feathers after lengthy swims.

During breeding season, some species develop ornamental crests, pouches, wattles or bright facial skin. These breeding characteristics quickly fade away after the mating season ends.

Diet and Hunting

Cormorants are supremely skilled at hunting fish and aquatic prey. They dive underwater and propel themselves with their large webbed feet to chase down fast-moving fish. A thin layer of air trapped next to the skin and feathers allows cormorants to stay submerged for lengthy periods. Some unique aspects of cormorant feeding include:

• Diet consists mainly of fish like perch, trout, bass, herring, eels and more. They also eat amphibians, crustaceans and insects.
• Can dive to depths exceeding 150 feet in search of prey.
• Eyes well-adapted for seeing underwater.
• Can stay submerged for up to a minute during longer dives.
• Swallow small fish underwater before resurfacing.
• Secrete a waterproofing oil that helps reduce wetting of the plumage.
• Often found in large feeding flocks around schools of baitfish.
• Young cormorants are fed by regurgitation.

Cormorants employ a range of hunting techniques depending on circumstances. They may chase individual fish, probe concealed spots, or stir up the bottom to flush out prey. Their long neck allows them to reach down and capture prey without having to fully submerge. It’s an efficient way to snatch a quick meal at the water’s surface.

Breeding and Nesting

Cormorants nest in large colonies, often returning to traditional sites year after year. Breeding activities include:

• Form monogamous pair bonds for breeding season.
• Build nests out of sticks, seaweed or other vegetation.
• Nest sites are typically low trees, rocky ledges, cliffs or islands.
• 3-5 pale blue or green eggs per clutch.
• Both parents incubate eggs for 25-30 days.
• Young fledge nest at 4-7 weeks old.
• Double broods common in some warmer regions.

Nesting colonies can number in the thousands of pairs in dense concentrations. This helps reduce individual predation risk. Cormorant guano or droppings can accumulate substantially at breeding sites. Historically this was mined as a fertilizer in some places.

The nests themselves are crude piles of sticks and vegetation, often reused year after year. The parents share incubation duties, switching off every 1-2 days. Once hatched, the chicks are blind and naked but grow quickly on a diet of regurgitated fish. Adults vigorously defend nests from potential predators.

Migration

Many cormorant species migrate or disperse based on seasonal food availability. Migration habits include:

• Northern breeders migrate south for winter.
• Summer dispersal of young birds from nesting areas.
• Opportunistic migration based on fish stocks.
• Migratory routes follow coastlines or large inland waterways.
• Strong fliers capable of long distance migrations.

The Double-crested Cormorant of North America migrates south along the Atlantic and Pacific coasts each winter. Great Cormorants in Europe and Asia make seasonal movements based on harsh weather and declining food resources. In warmer southern climates, cormorants may remain in the same area year-round if food is abundant.

Banding studies show cormorants are capable of remarkably long migrations of thousands of miles between breeding and wintering grounds. Their powered flight allows them to travel rapidly over open water compared to movement on foot.

Adaptations for Swimming and Diving

Cormorants exhibit many specialized adaptations that allow them to pursue fish underwater:

• Hydrodynamic body shape – Long neck, streamlined profile and muscular tail reduce drag.
• Powder down – Special down feathers distribute waterproofing oils.
• Wettable plumage – Allows water to penetrate feathers for less buoyancy.
• Feather muscles – Adjust feather overlap to regulate air trapped against the skin while diving.
• Keel – Extensive keel provides large surface area for flight muscle attachment.
• Webbed feet – Propels the bird underwater with powerful kicks.
• Sinuses – Air sacs and reinforced skull help withstand pressure changes.
• Vision – Excellent underwater eyesight to spot prey.

This combination of adaptations makes cormorants agile swimmers capable of chasing down fast fish prey. They are not quite as specialized for diving as seabirds like penguins and auks, but are more adept in the water compared to most other types of waterfowl.

Interestingly, cormorants have more vertebrae and greater backbone flexibility than other birds. This allows them to more efficiently propel themselves through the water in pursuit of fish. Their stiff tail provides a strong rudder to change direction.

Interaction with Humans

Cormorants have a complex relationship with humans, sometimes coming into conflict:

• Perceived as competitors by recreational and commercial fishermen.
• Shot or culled in some areas due to fish consumption.
• Historically hunted for meat, eggs, oil and feathers.
• Guano was mined for fertilizer.
• Suffered pesticide impacts and habitat loss.
• Nesting colonies can damage trees and impact vegetation.
• Increasing adaptation to man-made habitats like reservoirs and aquaculture.

On the positive side, cormorants help control fish populations and serve an important role in wetland ecosystems. Birdwatchers value them as a spectacular swimming and diving bird. Responsible management practices aim to balance cormorant populations, fish stock sustainability and human uses of waterways.

Some conservation measures include:

• Protecting key breeding and roosting sites.
• Monitoring populations and ecology.
• Sustainable hunting limits based on science.
• Non-lethal hazing at fisheries and aquaculture sites.
• Public education about cormorants.

Taxonomy and Classification

Cormorants belong to the avian order Suliformes which includes gannets, boobies, anhingas and frigatebirds. They are members of the Phalacrocoracidae family. Some taxonomy details:

• Order – Suliformes
• Family – Phalacrocoracidae
• Genera – Phalacrocorax and others
• Species – Varies by region, 40 currently recognized.

The genus name Phalacrocorax is Greek for “bald raven” referring to the white throat patches on some species. Regional names for the birds include shag, cormorant, king cormorant, great cormorant and black shag.

Extinct cormorant relatives in the fossil record indicate the family has been around since the Late Cretaceous period over 65 million years ago. Some ancient cormorant species evolved into enormous seabirds over 5 feet tall.

Population Status

Many cormorant species have adapted well to human changes to aquatic environments. They are not considered globally threatened for the most part. However, population trends vary by region:

• Increasing – Double-crested Cormorant, Great Cormorant, Black-faced Cormorant.
• Stable – Pelagic Cormorant, Brandt’s Cormorant, Red-faced Cormorant.
• Declining – Guanay Cormorant, Japanese Cormorant.
• Endangered – Spectacled Cormorant, Bank Cormorant.

Cormorants suffered from DDT pesticide impacts several decades ago but made strong recoveries after the chemical was banned. Ongoing threats include pollution, habitat loss, fisheries interactions and climate change. Responsible conservation practices will be needed to monitor vulnerable populations.

Responsible culling and sustainable hunting quotas have been implemented in some areas to alleviate fisheries conflicts. More research is needed to fully understand the complex ecological interactions at play.

Key Facts and Summary

To summarize key facts about the black diving bird known as the cormorant:

• There are around 40 species found worldwide near waterways and coasts.
• Dark plumage and long neck are hallmark identification features.
• Fish make up the bulk of their diet which they pursue by diving underwater.
• Special adaptations like webbed feet, wettable feathers and sinuses help them swim and dive.
• Build nests and breed colonially, often returning to traditional sites.
• Many species migrate or disperse based on seasonal food availability.
• They have a complex relationship with human fisheries but overall are not globally threatened.

So in conclusion, the common black waterbird well known for its fishing behavior and diving ability is undoubtedly the cormorant. They are a unique and iconic aquatic bird found throughout wetlands, lakes, rivers and coastlines across the world. Whether observed roosting with outstretched wings or swimming stealthily in search of a meal, cormorants are amazing birds perfectly adapted to life on the water.