Northern Gannet

About

The Northern Gannet is a large, striking seabird known for its spectacular plunge-diving fishing technique. Adults are predominantly white with black wingtips and a distinctive yellowish head. They are highly colonial breeders, forming dense colonies on cliffs and islands in the North Atlantic.

Size & lifespan

Length

87-100 cm (34-39 in)

Wingspan

165-180 cm (65-71 in)

Weight

2.3-3.6 kg (5.1-7.9 lb)

Lifespan

Up to 35 years in the wild, typically 15-20 years

Diet

Carnivore (piscivore)

Physical characteristics

Plumage

Adults are brilliant white with black primary flight feathers (wingtips). The head and nape acquire a yellowish wash, particularly pronounced during the breeding season. Juveniles are dark brown to black, heavily speckled with white, gradually becoming whiter over several years.

Beak shape

Long, conical, and sharply pointed. Pale bluish-grey with dark cutting edges in adults. Juveniles have a darker bill.

Eye color

Pale blue with a dark ring around the pupil, giving a 'staring' appearance.

Leg color

Dark grey to black, with greenish-yellow lines running down the front of the tarsus and toes, which are used in courtship displays.

Distinguishing features

Large size, pure white body with black wingtips, yellowish head (adults), and powerful, direct flight. The unique plunge-diving behavior from considerable heights is also a key identifier.

Juvenile appearance

First-year birds are entirely dark brown to black, heavily mottled with white spots and streaks, especially on the back and underparts. The bill is dark. Over the next 3-5 years, they gradually acquire adult plumage, becoming progressively whiter with each molt, retaining some dark mottling on the body and a dark tail until full maturity.

Seasonal changes

The yellowish wash on the head and nape of adults is most prominent during the breeding season. Otherwise, adult plumage is largely consistent year-round.

Sexual dimorphism

Males and females are outwardly similar in plumage and size. There are no significant visual differences.

How to identify

1. 1

   Size and Shape

   Very large, long-bodied seabird with long, pointed wings and a wedge-shaped tail. Appears powerful and streamlined in flight.

2. 2

   Plumage (Adult)

   Brilliant white body, black wingtips (primaries), and a yellowish wash on the head/nape. Look for the pale blue eye with a dark ring.

3. 3

   Plumage (Juvenile)

   Dark brown/black with white speckling, gradually becoming whiter over several years. Dark bill and tail.

4. 4

   Flight

   Strong, direct flight with steady wingbeats. Often glides on stiff wings. Can be seen soaring high above the water.

5. 5

   Feeding Behavior

   Distinctive plunge-diving from considerable heights (10-40m), folding wings back just before impact. This behavior is unmistakable.

6. 6

   Bill

   Long, conical, pale bluish-grey bill with dark cutting edges in adults.

Habitat & range

Biomes

Marine, Coastal

Geographic range

North Atlantic Ocean. Breeding colonies are found on islands and coastal cliffs of Canada (Newfoundland, Quebec), Greenland, Iceland, Norway, the British Isles (Scotland, Ireland, England, Wales), and France. Non-breeding range extends south to the Gulf of Mexico, West Africa, and the Mediterranean Sea.

Elevation range

Sea level to several hundred meters above sea level for nesting cliffs.

Preferred environments

Open ocean, coastal waters, and offshore islands or steep cliffs for breeding. They require clear, relatively shallow waters for foraging, often near continental shelves or areas with upwellings that concentrate fish.

Behavior

Activity time

Diurnal.

Feeding habits

Specialized plunge-divers. They spot prey (primarily fish like mackerel, herring, sand eels, capelin) from heights of 10-40 meters (33-130 ft), fold their wings back, and dive headfirst into the water at speeds up to 100 km/h (60 mph). They can pursue fish underwater using their wings and feet. Often feed in large groups, sometimes associating with whales or dolphins.

Social behavior

Highly colonial breeders, forming massive, dense gannetries. Outside the breeding season, they are largely pelagic but can be seen in groups at rich feeding grounds. They are monogamous, forming long-term pair bonds.

Flight pattern

Powerful, direct flight with strong, steady wingbeats. They can glide for long distances, especially when soaring on updrafts near cliffs or over waves. Often fly in V-formations or long lines when commuting to feeding grounds.

Migration pattern

Migratory. Northern populations (e.g., Canada, Iceland, Norway) undertake long-distance migrations south to warmer waters off the eastern US, Gulf of Mexico, and West Africa. Southern populations (e.g., British Isles, France) may be partially migratory or dispersive, with many birds moving south but some remaining closer to breeding grounds, especially in milder winters. Juveniles typically migrate further south than adults.

Territoriality

Highly territorial within the breeding colony, defending a small nesting site (about one meter radius) from other gannets with aggressive displays and bill fencing. They are less territorial outside the breeding season.

Breeding & reproduction

Breeding season

Typically from late March to August, with peak egg-laying in April-May.

Nesting habits

Nests are built on steep, inaccessible cliff ledges or flat tops of offshore islands. They are large, conical mounds constructed from mud, grass, seaweed, and often incorporating man-made debris like fishing nets or plastic. Both parents contribute to nest building.

Clutch size

1 egg

Egg description

A single, pale blue or greenish-blue egg, which quickly becomes stained brown by guano and nest material. It is relatively large, measuring approximately 79 x 49 mm.

Incubation period

42-46 days, shared by both parents.

Fledging period

90-97 days. Chicks are fed by both parents until they fledge. After fledging, juveniles are left to fend for themselves and undertake their first migration.

Parental care

Both male and female share incubation duties and feed the chick by regurgitation. Parental care is intensive until fledging.

Where to find

Field tips

1. Look for Plunge-Diving. Scan the horizon for birds circling high above the water, then watch for their dramatic, vertical dives. This is the most iconic behavior.
2. Observe Flight Patterns. Note their powerful, direct flight and long glides. They often fly in lines or V-formations when traveling to and from feeding grounds.
3. Visit Colonies in Breeding Season. For the best views and to hear their vocalizations, visit a gannetry during the spring and summer. Be prepared for strong smells and loud noise.
4. Distinguish Juveniles. Remember that young birds are dark and mottled, not pure white. Don't mistake them for other dark seabirds.

Similar species

Quick facts

Dive Speed:

Up to 100 km/h (60 mph)

Colony Size:

Can number in the tens of thousands of pairs

Diet Specialization:

Almost exclusively fish

First Flight:

Juveniles are heavier than adults when they fledge, relying on fat reserves for their first migration.

Fun facts

• Northern Gannets have special air sacs in their face and chest that act like airbags, protecting them from the impact of their high-speed dives.
• Their nostrils are internal and covered by a membrane, allowing them to dive without water entering their nasal passages.
• The name 'gannet' comes from Old English 'ganot', meaning 'gander' or 'strong male', referring to its powerful appearance.
• The Bass Rock in Scotland hosts the world's largest single colony of Northern Gannets, with over 150,000 birds during the breeding season.

Scientific classification

Kingdom

Animalia

Phylum

Chordata

Class

Aves

Order

Suliformes

Family

Sulidae

Genus

Morus

Species

Morus bassanus

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