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March 16, 2007

Año Nuevo Birds: Heaven for Hummingbirds

The Northern Elephant Seal mating season is coming to an end, and so this week I thought I would try to be more sensitive to the birds in the area. It seemed its peak time for hummingbirds. I couldn't walk more than a few feet without hearing the telltale chirping, inevitably finding a hummingbird at a top branch of the scrub. From most angles, they just look like normal little birds. Then suddenly, they turn slightly and their bright iridescent feathers flash.

Just like the elephant seals, hummingbirds (Family Trochilidae) display traits of sexual dimorphism, or sexual differentiation. Much like peafowl, the males are the colorful ones and the females aren't so much. There are about 330 species of hummingbirds in the world, and they are all in North and South America. Many of the species exist only in the tropics and the Cuban Bee Hummingbird (Mellisuga helenae) is the world's smallest bird.

The bee hummingbird is the world's smallest homeothermic [warm-blooded] vertebrate. When flying, its wings beat 80 times per second, up to 200 times per second during courtship displays. Its heart rate is the second fastest of all animals. Bee hummingbirds also have the fewest feathers of all birds. Their body temperature is 40 °C (104 °F), the highest of all birds

More At: Wikipedia: Bee Hummingbird

And talk about a sugar high, these tony, ultralight birds can consume up to half their body weight in sweet nectar every day! This helps them beat their wings more than 100 times per second and fly at speeds of up to 60mph. Still, they are preyed upon by birds of prey as well as domestic and feral cats.

Some hummingbird species migrate hundreds of miles yearly, over land and open ocean. The Rufous Hummingbird can migrate 2000 miles from Mexico to Canada and Alaska, but not Hawaii. So why are they only found in the New World? Unfortunately, the fossil record isn't much help in terms of hummingbirds.

...these little birds are durable only in life. In death their delicate, hollow bones almost never fossilize. This was one reason for the astonishment that greeted the recent discovery of a jumble of 30-million-year-old fossil bird remains that may include an ancestral hummingbird. Like modern hummers, the fossil specimens had long, slender bills and shortened upper wing bones topped by a knob that may have let them rotate in the shoulder socket for hovering flight.

The other surprise was where the fossils were found: in southern Germany, far from modern hummingbird territory. To some scientists, the discovery shows that hummingbirds once existed outside the Americas, then went extinct. Or maybe the fossils weren't true hummingbirds. Skeptics, including Schuchmann, argue that other groups of birds evolved hummingbird-like characteristics many times through the eons. True hummingbirds, says Schuchmann, evolved in Brazil's eastern forests, where they competed with insects for flower nectar.

More At: National Geographic: Hummingbirds - Flight of Fancy

And again like elephant seals, hummingbirds are extremely territorial. They fight over food and territory but are rarely injured in these displays. Funny how such different species can be display such similar behaviors!

Posted by sorsha at March 16, 2007 8:46 PM