Northern Gannet (Morus bassanus)
● Appearance: mostly white; long, black-tipped wings; pale yellow feathers on head and neck; long, straight, grey beak; black webbed feet, black eye ring
○ Males are larger than females, females are heavier, same coloration
○ Males have yellow-green line running down legs (top right), females have blue-green line (bottom right) – breeding season beaks take on blue hue and yellow feathers brighten
● Length: 40-43 inches (about 3.5 feet)
● Wingspan: 70 inches (about 6 feet)
● Status: populations are stable, may be slowly increasing
○ Almost hunted to extinction in 1800s for plumage and eggs, especially in Canada
● Habitat
○ Open water, spend most of lives above open water, occasionally return to shoreline to roost, breed, or seek shelter from storms
○ Found offshore along the east coast of North America
○ One of largest seabirds in the Northern Atlantic
○ Worldwide, this bird is also found in the U.K. and Scandinavian Peninsula (Norway, Sweden, Finland)
● Diet
○ Feed on various types of small fish and squid
○ Flies over open ocean and scans for prey at the water’s surface
○ Plunge-dives from 30-130 feet in the air
○ Stay underwater for average of 10-20 seconds before resurfacing
○ Specialized eye lenses change shape once they dive into water, so they have sharp vision both midair and underwater
○ Also forage while swimming after diving or floating on water’s surface
○ May attack other birds to steal their food midair
○ Swallow fish underwater so that other birds do not steal them
○ Other large seabirds, such as skuas and jaegers, force northern gannets to regurgitate food
○ Broad wings and bullet-shaped body allow for quick, skillful maneuvers mid-flight
○ Small pieces of PLASTIC, if eaten, can cause indigestion or starvation
● Migration
○ Breeding season lasts April-June, raise young until September, leave breeding grounds soon after young’s first flight
○ Outside of the breeding season, northern gannets disperse over a wide area, normally travel within 500 to 1,000 miles of breeding grounds
○ Can reach flight speeds of more than 60 mph
○ “Vagrant” – travels 35-145 miles to forage, may travel up to 335 miles each day
● Nesting
○ Nest on offshore islands or steep cliffs inaccessible to land predators
○ Social birds – often forage and nest in colonies by the hundreds or thousands
■ This creates competition for space and food
○ Males and females return to same breeding grounds each year, may mate for life
○ Male arrives first, protects territory, then greets female with a bow
○ Both parents extremely territorial, fights with other birds may result in death
○ Nest is large, compacted pile of mud, seaweed, grass, flotsam, and feathers, parents cement materials together using guano – mostly male’s job
■ Parents add to nest each year, eventually becomes tall mound
○ Average brood is 1 egg per season
○ Both parents feed young, since they only lay 1 egg per season and due to long maturation period of young, parents must invest all their resources into chick
○ PLASTIC poses huge problem for northern gannets: they can become entangled in trash parents use to make nest as chicks, trash tightens on them as they grow which can suffocate them, cause leg or wing deformations, sever their leg, or cause them to starve because they cannot forage
● “Young of the Year”
○ Juveniles are brown with white speckles
○ Young take their first flight after about 80-100 days
○ As they mature, northern gannets transition from brown to white feathers, gives patched appearance
○ It takes 4 years before maturity is reached and adult plumage comes in
○ Juvenile mortality can be as high as 65%, but once adults live for about 20 years
