BIRDS OF NANTUCKET
FIRST AMONG BIRDS? RUBY-THROATED HUMMINGBIRD
by Kenneth Turner Blackshaw
Have you ever seen a hummingbird? Most people remember being awestruck by the way they dart and hover, sometimes right in your face, their wings a blur. Nantucket is not the greatest spot to find them but they are seen every year and even known to nest.

Ruby-Throated Hummingbird

But - first among birds? Why would that be? It stems from the genus name that German ornithologist, Heinrich Gottlieb Ludwig Reichenbach gave it back in the early 19th century - Archilochus. The literal translation is "a chief among a body of people," but the intent was to show this tiny bird's place in the bird kingdom.

The whole concept of a hummingbird really blew scientist's minds in Europe. It is a New World family and they'd seen nothing like them. Initially they only were privy to info on the Ruby-throated Hummingbird of the eastern U.S., but by 1890 they had catalogued 18 species for our country. There are now known to be at least 325 hummingbird species, most of them in Central and South America.

Hummingbirds are part of a large order of birds known as Apodiformes that translates to "footless ones." They do have feet but only use them for perching. They don't walk or hop. With their flight skills, walking is quite unnecessary!

The Ruby-throat is the only hummingbird you are likely to find on our island. Its Latin species name, colubris, is another puzzle because it means "a serpent." This is probably another example of how a spelling error can creep into science since the French word for hummingbird is calibre.

Hummingbirds are amazing creatures to the point that at one time scientists felt they were truly impossible creatures. With wings that beat as many as 70 times a second and a heartbeat sometimes over 1,000 beats per minute in flight there was no possible way they could ever take in enough food to just keep from burning themselves out. Not only that, hummingbird hearts are five times as large as human hearts when compared to body weight. So each heartbeat would pump a proportionately huge amount of blood.

The only thing that saves them is what happens to them at night. In sleep hummingbirds revert to a state known as torpor. All their body functions slow down and their frantic heartbeat slows to just 40 beats a minute. Their breathing is all but undetectable.

Robert Krulwich recently did a program on National Public Radio titled "Size Matters: The Mathematics of Life." The subject was longevity. Why do small animals live so much shorter lives than large ones? The mathematical connection was the number of heartbeats. The common factor came out that hearts generally last for about a billion and a half beats. Large animals have a very slow pulse.

The Ruby-throated Hummingbird's frantic beat would give it less than a three-year life span using this formula. Yet we have a longevity record of over

nine years for one of these little charmers. That slowing

of the heart rate during sleep could account for that.

The hummer's annual cycle also creates risk that might shorten life. Most of them make a round trip from the Eastern USA across the Caribbean to South America and back. Fishermen in the Gulf of Mexico report them zooming busily along 25 feet above the waves heading north in the spring. There better be a lot of nectar available when they land.

That is another key to their survival. What they eat provides them with a high-energy boost, flower nectar and tiny insects. If you want to provide feeders designed to entertain them, be sure to mix a one to four sugar to water mixture to keep their little engines fueled. There are at least three feeder locations on the island successfully hosting hummers this summer.

On Nantucket we look for the first Ruby-throats to arrive early in May and most are gone by the end of September. They probably nest here every year but only a single nest has ever been found, in a pitch pine growing along the road leading to the sewerbeds back in 1949. But when you consider how tiny the nest was, only the size of a walnut and woven of spider silk and lichens, it's a miracle it was ever found at all.

We have a single record on Nantucket for one of the western hummingbirds, an Allen's. This was a much-weakened bird that was caught in a banding net back in late August of 1988. It passed away but now resides in the Museum of Comparative Zoology in Cambridge where it was positively identified.

As we get into September the Ruby-throats that pass through are mainly birds that have hatched this year in the Maritime Provinces of Canada and are making their first trip south. Often they go by so fast that birders have little time to be aware of them. You'll hear a birder exclaim "There goes a hummer," and you'll see a dot vanishing in the distance.

Remember if you are lucky enough to catch a glimpse of one, you'll have seen the "first among all birds!"

I

George C. West creates illustrations for these articles. The Maria Mitchell Association sponsors bird walks on Tuesday and Thursday morning starting at 6:30 a.m., 8 a.m. on Saturday, from the corner of Vestal and Milk Streets. There is a fee. To hear about rare birds, or to leave a bird report call the Massachusetts Audubon hot line at 1-781-259-8805. Ask Ken a question at: kenandcindy1@comcast.net.