Saturday 27 February 2016

Galapagos Islands Frigate Birds - The Dating Game

Galapagos Frigate Birds
The mating ritual of Galapagos Frigate Birds reminds me of going to a bar where the girls pick up the guys. In this case, the males sit in tree branches, rather than on bar stools.  And the females fly and circle above, examining each of the male specimens, assessing them, listening to their banter and ultimately making a decision.  It's quite an interesting and rather noisy process, but it seems to work for the Frigates.

Mating Pose
When you go to North Seymour Island in the Galapagos Islands, you will see this ritual repeated over and over again.  In their effort to attract a mate, the males perch in the trees in groups, puff up their bright red pouches, extend their considerable wings (with spans of about 6 feet in width) and put on a display for the rather plain (in comparison) females who circle above.  The males call out to the girls, sounding either like a drum or a trumpet (the sound depends on whether they are Great or Magnificent Frigate Burds) and eventually strike the fancy of one of them.

Why exactly one female picks a particular male is a mystery, but it works for the pair.  Soon, they are engaged in a ritual mating dance. 

Galapagos Frigate Bird Pair
I've seen pairs be very protective and even affectionate with one another, as in this photo - one of my personal favorites. But note too that the female is far larger than the male, an interesting anomaly of the species.

Galapagos Frigate Bird Chick
Together they build a nest, with the male providing the material and the female doing the actual construction.  Once an egg is laid by the female, the male and female take equal care incubating and protecting it.  Sometimes the male goes for food, sometimes the female.  Either way, the egg is protected by the other part of the couple. It takes just about two months before the egg hatches.

Galapagos Frigate Birds Parent Feeding Chick
Even after the chick is hatched, the parents take equal responsibility for providing nourishment in the first two or three months of its life. To get the baby's food, the parent flies out to the sea, swoops down and steals their catch from weaker marine birds, and then brings it back for the baby.  Ultimately the male will leave the nest before the female - and before the chick is fully fledged.  The female will stay with the baby another three months until the chick is able to fly.

Galapagos Frigate Bird Chick
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Thus, a young Frigate Bird actually is taken care of by its parents well into adolescence.  Because of the weight of its wings, a newborn may take as long as 5-6 months before it can support its own weight and fly.  Even then, it has to learn how to be a pirate before it can fend for itself, requiring that the female remain with the adolescent bird for as many as nine additional months.

Galapagos Frigate Bird Adolescent in Nest

The length of time it takes for the chick to be independent makes for another interesting fact.  Because the male frigate bird is "off duty" after just about 12 weeks, it can mate every year.  The female, on the other hand, has at least 10-12 months to dedicate to the newborn, thus is takes a new mate only every other year.  In this way, the total population of Frigate Birds stays stable.

For more information about the Galapagos Frigate Birds see my earlier posts Pirates of the Sea and Great and Magnificent.

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