Dec 102009
photo provided courtesy of cianc on Flickr Creative CommonsHomeNorth Atlantic, Mediterranean
Habitatopen ocean and rocky land (roosting)
Nicheaerial diving predator
Favorite Foodherring and mackerel
Wingspanbetween 5 and 6 feet
Weightup to 6.5 pounds

Northern gannets are the ultimate aerial divebombers of the world’s oceans. Floating on thermals above the cold waters of the North Atlantic, these birds use their keen binocular vision to locate fish swimming just below the surface of the water. Once it zeroes in on a fish, its spectacular attack begins. Sometimes from heights of more than 100 feet, a northern gannet will suddenly fold its body into a wedge shape and dive towards the water. Striking the surface at speeds upwards of 60 miles per hour, this torpedo of a bird impales and gobbles up the slippery fish with its dagger-like beak before powering back to the surface with its fin-like wings and webbed feet.

Northern gannets are perfectly adapted for life in three different realms of the Arctic: the air, water, and land. Although clumsier on the rocky outcroppings than other birds, gannets have few rivals when it comes to flying and swimming. Their streamlined shape is without equal, allowing them to penetrate the water with the speed of a car flying down the highway. Their adaptations have made northern gannets one of the most successful and plentiful sea birds on earth.

Nesting is an complex affair for these birds. Gathering in colonies that number in the tens of thousands every spring, northern gannets conduct elaborate courtship displays, dances, and rituals in order to find and keep mates. Once together, a pair of gannets will remain together for several years and will seek out the same nesting site every season they return. Although these birds are most at home in the air and powering through the water, they’re still tied to the land in order to rear their young. After mating, a single egg is produced and is guarded ferociously by both parents. Since nests are spaced a mere one or two bird lengths from neighboring parents, the potential for confrontation between adults is high. Both male and female will attack invaders with gusto, stabbing with their formidable beaks and battering their foes with their strong wings.

Northern gannets tend to produce their offspring around the availability of their favorite food, mackerel and herring fish. Like blood in the water to sharks, the large shoals of fish attract chaotic feeding frenzies of gannets requiring food for their young. One parent will guard the chick while the other goes out to hunt. When the hunter has returned, the youngster can enjoy a plentiful supply of barfed-up fish from its mom or dad. Because of the relatively secure system of gannet parenting and a plentiful food supply, most northern gannet chicks survive into the juvenile stage of life. However, as many as half will not survive the first major migration south that the birds undertake every year. After 3 months, the chicks are on their own, and without the aid of their parents on the demanding journey, many will perish.

Cruising the air and dominating the water, the northern gannet is one of the most successful birds on earth and is a story of an evolution honed to perfection.

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