Tuesday, January 12, 2010

The odd couple

PBS' Nature series on Sunday night had a feature on the amazing hummingbirds. They are the smallest warm-blooded creatures on the face of the earth and they live only in the Americas. There are more than 300 species of the little critters. Their hearts beat more than 600 times a minute under normal hummingbird activity. At night, when they enter a state called torpor in order to save energy, their heart rate can drop as low as the 30s and their temperature can drop from about 110 degrees down to the 50s. Some species of these tiny creatures, such as the Ruby-throated Hummingbird, make a migratory flight of some 600 miles one way, twice a year. These are creatures for which the adjective "amazing" truly fits. I would even venture to use that greatly overused adjective (which I normally abhor) "awesome".

I didn't get to see Nature on Sunday, but I DVR'd the show and watched it during lunch today. Of all the remarkable parts of the story, one particular bit of the hummingbird saga struck me as especially remarkable. It involves the Black-chinned Hummingbirds that nest in the Chiricahua Mountains of Arizona.

It seems that these particular hummers have figured out a unique way to protect their nests. They need protection because hummingbirds are prey for many other birds, reptiles, and small mammals. But there is a predator that is death on wings to all these animals that would eat the hummingbird and its eggs. It is the Cooper's Hawk.

The Cooper's primary prey is other birds, but the hummingbird is too small to attract its interest. It will also eat reptiles and small mammals when they present themselves as ready targets. It is a very efficient and deadly hunter and the hummingbirds have learned to take advantage of this.

The female Black-chinned Hummingbird finds where the Cooper's has built its nest and then she builds her nest in close proximity. In fact, one Cooper's Hawk nest may have several little hummingbird nests clustered around it. Since the Cooper's Hawk will clear the area of the animals that might prey on the hummingbird in order to feed itself and its chicks, the hummingbird and its nest gain protection.

Now, how did this tiny bird figure this out? It's just another example of how the word "birdbrain" is not necessarily derogatory.

4 comments:

  1. The hummingbird lives near the Cooper's hawk for the same reason the beautiful bluebird and the saucy mockingbird live near me. Why? Safety? Proximity to certain foods? It would take someone smarter than I to figure that one out.

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  2. Are the bird's actions pure instinct or is reasoning involved? And isn't instinct, too, a kind of intelligence? It's a complicated issue. Certainly not one that I can resolve.

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  3. Hi Dorothy! I certainly enjoy your blogs, but this is the first one I'll be commenting on :)

    I watched this PBS Special over and over as I was completely amazed by it. (I DVRd it, too), ... I'm in the birding business (I sell hummingbird feeders online) and was fascinated by the fact that they find that building their nests near the Cooper's hawk gives them refuge from other predators.

    This documentary was surely captivating. And your thoughts on it were certainly appreciated!

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  4. Thanks for your comment, Lindy. Glad to have you aboard. Hummingbirds are certainly among the most amazing creatures in Nature and the PBS show ALMOST did justice to them I think. It was thoroughly enjoyable.

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