Don Lyman
The Boston Globe, June 17, 2021
A ruby-throated hummingbird hovers near a backyard feeder at a Pembroke home.
JOHN TLUMACKI/GLOBE STAFF
In March of 1982, during my college spring break, I flew to California to visit a friend. I had never been out west, and being interested in biology, I wanted to see the desert. Steve, who was very knowledgeable about the natural history of California and the desert, took me camping in Anza-Borrego Desert State Park, about 80 miles east of San Diego.
It was a wonderful experience, and I saw lots of plants and animals I had never seen in the wild ─ cactuses, jackrabbits, desert lizards, and so on.
One of my most lasting memories from that trip was of a female Costa’s hummingbird feeding on the nectar from the bright red tubular-shaped flowers of an ocotillo plant. For several minutes, I sat mesmerized as the tiny greenish-colored bird zipped from one flower to the next along the length of the ocotillo’s long, spindly branches, silhouetted against the clear blue desert sky, while the Seals and Crofts song “Hummingbird” played in my head.
“Hummingbird, don’t fly away, fly away …”
With beautiful jewel-like iridescent colors, wings that beat in a blur, and amazing maneuverability, hummingbirds seem almost magical.
There are 349 species of hummingbirds, all of which live in the Americas, according to Cornell University’s “All About Birds” website. Most of those species are found in the tropics. Thirteen species spend at least part of each year in the US. But only one, the ruby-throated hummingbird, breeds in the eastern United States, including Massachusetts.
Each year, these tiny summer visitors fly thousands of miles from their wintering grounds in Mexico, Central America, and south Florida, said Wayne Petersen, director of Mass Audubon’s Important Bird Areas Program.
“Many of them even cross the Gulf of Mexico non-stop – a distance of 500 to 600 miles,” said Petersen. “They’re very fast and efficient fliers.” The wings of a ruby-throated hummingbird beat about 53 times per second, according to the Cornell website.
“Their muscular articulation and wing structure is different from other birds,” said Petersen, “which allows them to go up, down, and backwards. They’re adaptive for nectar feeding — they hover in front of flowers. They’re metabolically remarkable.”
Robert Dudley, professor and chair of the Department of Integrative Biology at the University of California, Berkeley, wrote in an e-mail that flight speeds of hummingbirds typically seen moving quickly in parks and between flower patches/feeders would likely be 5-10 meters/second (11 to 22 miles per hour).
Dudley, who conducts research in the Animal Flight Laboratory at Berkeley, said that the in-flight heart rate of ruby-throated hummingbirds is about 20 beats/second.
Ruby-throated hummingbirds burn energy so quickly, they have to eat more than their own weight in insects and nectar daily to survive, according to Mass Audubon’s website. To stay alive when no food is available, hummingbirds enter a state called torpor, similar to hibernation, where their metabolism slows down substantially.
Ruby-throated hummingbirds typically arrive in Massachusetts in late April and into May, said Petersen. The males have green feathers on their back, and bright red gorgets — the colorful throat patches common to many hummingbird species. But the males’ throats aren’t always red, said Petersen. The feathers on the gorget are iridescent, and their color changes depending on how the sunlight is hitting them.
“The colors of the gorget feathers are not due to pigments,” explained Petersen. “The gorget feathers are like prisms, and they reflect sunlight in different ways. The feathers will light up when the sun hits the gorget the right way. But the color will go gray if the hummingbird moves a little.”
Ruby-throated hummingbirds nest in May and June, said Petersen. Their nests are built directly on top of branches and measure about 2 inches across and an inch deep, according to the Cornell website. The nests are made with plant fibers and lichens, and are held together with spider webs.
They typically lay two eggs, which are white and only about half an inch long, said Petersen. The eggs hatch in about two weeks. The young are fed nectar and insects, and leave the nest in about 19 days. Ruby-throated hummingbirds can live to be 7 or 8 years old.
Ruby-throated hummingbirds usually feed on the nectar of red or orange tubular flowers such as trumpet creeper, cardinal flower, honeysuckle, bee-balm, and jewelweed, according to the Cornell website. Hummingbirds also catch insects such as mosquitoes, gnats, and fruit flies in midair or pull them out of spider webs. They also eat spiders. Adult ruby-throated hummingbirds range from 2.8 to 3.5 inches long, and weigh from 0.1 to 0.2 ounces.
Petersen said hummingbirds will even be attracted to artificial colors, such as red-colored clothing. I saw this happpen once when my friend Steve and I were hiking in New Mexico. Steve was wearing hiking shorts and athletic socks. His socks had red colored bands on them, and a hummingbird actually flew up to his socks and poked at the red bands with its bill!
Hummingbirds have long tongues, with brush-like tips, said Petersen. When feeding they insert their bill into flowers and flick their tongue. Hummingbirds also function as pollinators, transferring pollen from one flower to another.
Some people put hummingbird feeders filled with sugar water in their yard to attract hummingbirds during the summer. The color of the feeding port is what attracts hummingbirds, so most feeders are red, said Mass Audubon, which recommends cleaning feeders at least weekly.
Male ruby-throats begin their southward migration in August, said Petersen, and the females follow in September.
Even though they’re small, hummingbirds are feisty and can be aggressive, Petersen said. Some hummingbirds will bump other hummingbirds at feeders. “They may be tiny,” said Petersen, “but they’re mighty little warriors.”
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