- Appearance: white head and belly, dark grey (“black”) backs, black on tips of wings, white on undersides of wings, beige legs, yellow beak with red spot near tip
- Identical plumage coloration, but male is larger
- Length: 28 to 31 inches (about 2.5 feet)
- Wingspan: 57 to 63 inches long (about 5 feet)
- Status: common, populations increasing
- Almost hunted to extinction during era of feather trade in 1800s
- Habitat
- Mainly found on Atlantic coast of North America, but seen at large inland bodies of water such as the Great Lakes
- Also found in Northern Europe
- Forage in open ocean, along coastline, and around fishing docks
- Rest (“loaf”) in open areas such as fields, parking lots, piers, and runways
- Airports must scare gulls off runways to avoid collision with planes
- Often perch on roofs of buildings as well
- During the 1900s, their range expanded, probably due to the establishment of landfills and other sources of human refuse during the Industrial Revolution
- Black-backs are the largest species of seagull in the world
- Mainly found on Atlantic coast of North America, but seen at large inland bodies of water such as the Great Lakes
- Diet
- Black-backs forage with other gulls, usually herring gulls
- Opportunistic feeder, eat almost anything they can find
- Mostly skim water for fish, crustaceans, and their eggs
- Drop shellfish on rocks or docks to crack shells
- Scavengers – often eat carrion
- Steal food from other seabirds, sometimes eat their eggs and young
- Eat scraps of food from beachgoers, bait discarded by fishermen, and garbage from the ocean and landfills
- Black-backs can become ill or even die if they ingest plastic
- Migration
- Most black-backs remain near their breeding grounds year-round
- They may move farther inland to avoid clustering in colonies, but they do not travel long distances or follow a set path – dispersive migration rather than seasonal migration
- Breeding populations in northern Canada often migrate down to warmer regions
- When they move long distances, they follow the coastline or major rivers
- Average flight speed is between 20-25 mph, top speed is about 35-40 mph
- Most black-backs remain near their breeding grounds year-round
- Nesting
- Black-backs breed in areas naturally protected from predators
- Rocky islets, salt marshes, barrier beaches or islands
- Form colonies with other gulls, terns, and other shorebirds
- Uncommon, but some breeding choose an isolated nest site
- Nest in open habitat close to water, seek patches of vegetation to hide their eggs
- Ideal places for seagulls to nest are those frequented by beachgoers, therefore, they have adapted to new nesting environments
- Sometimes displace laughing gulls and herring gulls from their nesting habitats when theirs is lost to storms or human activities
- Males and females both scratch depressions into ground above tidal range
- They choose the best spot to line their nest with pebbles and vegetation
- Breeding pair returns to the same site, but not the same nest, each year
- They often return to the same mate as well
- Average brood is 2-3 pale greenish-brown eggs with dark brown/ olive speckles
- Black-backs are comfortable around humans, but fly away if closely approached
- Black-backs aggressively defend their territory against dogs, cats, eagles, and other potential predators – they have been known to chase humans
- Black-backs breed in areas naturally protected from predators
- “Young of the Year”
Chicks begin exploring 1 day after hatching, but do not leave nest until about 40 days
-
- At 45 days fledglings learn to fly and leave nesting territory, but parents feed them for 3-4 weeks while they learn to forage
- Plumage transforms from brown blotches to black blotches, then head/belly/tail whiten and beak yellows as adult feathers come in
- It takes about 3 years for a young black-back to sport adult feathers
- Average lifespan is 25-30 years, but a 45 year old lives in captivity in Europe
- At 45 days fledglings learn to fly and leave nesting territory, but parents feed them for 3-4 weeks while they learn to forage
