Northern Gannets - Backshore Peaks Island    

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Northern Gannets - Bird Rock @ Cape St. Mary, Newfoundland                                    Photos © Patty Wainright

 

Northern Gannets


Gannets at a Glance

 

Taxonomy

  • Order Suliformes (includes gannets/boobies, cormorants, darters, and frigatebirds)

  • Family Sulidae - Gannets and boobies – 9 species

            Mostly tropical except the Northern Gannet

            Most closely related to the cormorant family

  • Genus and species:

            Sula bassana

 

Identification

  • Large size (37” long; 72” wingspan; 6.6 lb.), conspicuous, perfectly streamlined white bird with black wing tips, flying high over sea

  • Head is a peach color with long pointed bill

  • Immature gannets have an overall brownish-grey body

  • Continuous molt as compared to other birds

  • Avoids periods of relative incapacity for effective plunge diving

 

Behavior/Habitat

  • Marine/pelagic, except for breeding

  • Binocular vision (eyes placed forward) used to locate prey

  • Once fish shoals are seen, gannets stall and plunge dive for fish

  • Reach 10-16’ beneath surface, deeper to 30’ using wings to “swim”

  • Swallow fish as they ascend to the surface

  • Stall at the surface, face wind and flap powerful wings to fly

  • Pair for life and reunite after wandering at sea in the winter

  • Extensive pair bonding upon return to breeding sites

 

Breeding/Nesting

  • Breed on cliffs of eastern and western Atlantic shorelines/islands

  • Gulf of St. Lawrence, northern Nova Scotia, Newfoundland, Labrador

  • Colonial nesting

  • No brood patch (allows for a more streamlined body)

  • Egg is incubated on the webs of feet; usually 1 egg

  • Incubation is 44 days by both sexes

  • Fledge in 90 days

  • Sexually mature at 3-6 years

 

Migration

  • Migrate in short lines, flying south from breeding locations

  • Migrate over continental shelf off East Coast of North America

  • Immature gannets migrate as far as Gulf of Mexico to avoid winter hardships at sea

  • Older birds stay as close as possible to breeding grounds; expedites return to nest sites that are in high demand

 

 

 

Full Species Account

 

Poets consider the Northern Gannet (Sula bassana)(gannets) as a symbol of a perfect marriage between wind and sea.  They fly with grace and force, delicacy and strength – in a world where man is vulnerable (1).  Northern Gannets belong to the Family Sulidae (within the ancient Order Suliformes), sharing this family with the boobies (e.g. Blue-footed Booby of the Galapagos). 

 

Gannets breed on both sides of the Atlantic Ocean.  Those gannets breeding in Canada (e.g. Bird Rock @ Cape St. Mary, Newfoundland) migrate southward in the autumn dispersing over the continental shelf.  They stay well off shore during their non-breeding season, usually off the southern seaboard.  Immature gannets sometimes travel as far as the Gulf of Mexico, avoiding winter hardships at sea.  During the 19th century the gannets were nearly exterminated in the Gulf of St. Lawrence and eastern Canada.  The gannetery at Bird Rock contained up to 125,000 breeding pairs and by 1932 there were only 500 pairs (1).  The numbers have rebounded to 24,000 individuals (5).

 

Using their binocular vision (both eyes are oriented toward the front) gannets can fly at great heights to locate fish.  Their wings are long and set back on the body allowing for high wind cruising (dynamic soaring).  In normal flight powerful flaps of these wings are used, interspersed with gliding.  Their wing configuration (wings held backward and in line with the body, taking the shape of a dart) also allows for efficient plunge diving (3).  Spectacular plunge dives from great heights permit the gannets to reach deeper depths (10-16 feet) than other seabirds in search of fish (1).  Greater depths of 40-50 feet can be reached by using their wings to ‘swim’ (3). 

 

These spectacular plunge dives can be observed off Peaks Island Backshore during storms that bring them close to shore.  The most striking characteristics for offshore identification of the Northern Gannets are their very large size (compare to the Bald Eagle); their striking and streamlined body; a white belly and chest; and their black wingtips.  At close view, a light cream/orange head can be seen.  Immature gannets are generally a uniform gray-brown, as are immature gulls.  Gannets mature at 3-6 years, then attaining their white plumage. (1)

 

 

References

1. del Hoyo, J., Elliott, A., and Sargatal, J. eds. (1992). Handbook of the Birds of the World. Vol. 1. Lynx Edicions, Barcelona (pages: 312-325; 536-628).

 

2. Sibley, D.A.  (2000). National Audubon Society: The Sibley Guide to Birds.  Alfred A. Knopf, Inc. NY (pages: 54; 98-99).

 

3. Sibley, D.A. (2001). National Audubon Society: The Sibley Guide to Bird Life and Behavior.  Alfred A. Knopf, Inc. NY (pages: 154-156; 190-211).

 

4. Northern Gannet Wikipedia

http://en.wikipedia.org/wiki/Northern_gannet

 

5. Cape St. Mary’s Ecological Reserve website http://www.env.gov.nl.ca/env/parks/wer/r_csme/)

Type in: Cape St. Mary's Ecological Reserve

 

Written by: Patty Wainright

Reviewers: Michelle Brown, Linda Sauerteig, Sam Wainright

© Peaks Island Land Preserve