February 16 2009 Page 4 Features, Weather, Sports, Exchange

Magnificent Frigatebird: Ocean Thief

Tara Spears

                Second in seabird series.

Next to the chunky pelican, the streamlined frigatebird looks aristocratic.  Thousands of these sleek seabirds live along the Riviera Nayrit coast.  When newly settled here I was walking the beach with my little dog and enjoying the flight of the seabirds until one of the large birds flying overhead lost its grip on dinner and it landed right in my path: a gigantic, live sea snake! I trotted home to identify this greedy bird that would grab a two meter long lunch.  Sure enough, the frigatebird is nicknamed ‘pirate bird’ for its propensity to steal food from other birds by snatching food dropped by other birds before it hits the water.

  As the photos illustrate, the frigatebird has an incredible flying ability, owing to their wingspan of over 2 m/6.5 ft with less than 2 kg/4 lb of bodyweight to support.  The distinctive hooked grey beak and long split tail make them easy to recognize.

The Magnificent Frigatebird's long, swallow-like tail enables it to make sharp turns, and its long, broad wings lift the bird with little effort. The Magnificent Frigatebird is most at home in the air because its short legs cannot walk, and its feathers absorb water, so it rarely rests on the ocean. It is interesting that the same species has coloration differences according to age and sex.  Females can be as much as 23% larger than males. Adult males are black with greenish shading over the back and a bright red throat sac that is usually deflated. Females are black overall with a whitish bar in the upper wings and a white vest across the chest. Young Magnificent Frigatebirds are also black, but with a white head, chest, and belly.

Magnificent frigatebirds are usually seen flying high on the air currents or gliding down to the water to snap up fish and squid. Because its feathers soak up water, the birds dive only briefly in pursuit of prey or a drink.  Although this seabird primarily eats fish, their diet is supplemented by fishery waste, immature seabirds, young turtles, and small crabs. That’s why so many congregate near the local fish markets: to feast on the entrails the fishermen toss out.

This sleek seabird doesn’t reproduce until nine years old and lives for about 30 years.  Females do not breed every year because it takes a year and a half to raise a chick. It has been observed that males are believed to breed every year (with a second female). Unlike some other seabird species, the magnificent Frigatebird does not stay loyal to nest sites or its mate.

The frigatebird’s rough nest is constructed in low trees or on the ground on remote islands, such as lie in the Jaltemba Bay.  A single egg is laid each breeding season with both parents covering it for about four months until the hatchling grows feathers. The mother frigatebird stays with her young for another six months.  The duration of parental care in frigatebirds is the longest of any bird.

Watching these graceful thieves is another great Mexican beach pastime!

Male frigatebird courting behavior:    

Contact Tara:   tara.sprs@hotmail.com

children at Casa de Los Ninos