The Blue-throated is the largest hummingbird found in North America. At 4-1/2” to 5-1/2”, it is just barely bigger than the Magnificent Hummingbird. Blue-throats are much more common south of the border, where they range as far south as Oaxaca. In summer, they cross over into Ramsey Canyon in the Huachuca Mountains, Madera Canyon in the Santa Rita Mountains, and Cave Creek Canyon in the Chiricahua Mountains. We’ve seen them at feeders in Summerhaven on Mount Lemmon.
They are considered “uncommon” here in Arizona. In the Chisos Mountains in the Big Bend National Park in Texas, they are fairly common in the cypress-pine-oak habitat from June to September. There are rare but almost annual reports of a Blue-throat coming to feeders in the winter from Portal and Ramsey Canyon.
They are usually found along wooded streams in mountain canyons where the vegetation is lush. Keep an eye out for it if you find yourself in such places. They’ve also been seen occasionally in southern New Mexico in the San Luis and Guadalupe Mountains. In Arizona, New Mexico and they are usually found fairly low in the mountains, but in Mexico they range up to 12,000 feet.
Both male and female Blue-throats are metallic green above. The adult male’s throat is bright, metallic blue, which can vary from greenish to a slightly violet hue. The female’s is grey. Both sexes have broad blue- black tails with broad white tips on the outer feathers. The birds often fan their tails which reveals the white tips. Although the female Magnificent Hummingbird also has white spots on the outer feathers of her tail, the Blue-throat’s white areas are larger and purer white. You can also see a rather conspicuous white eye stripe, and a fainter whisker stripe bordering a dark ear patch. The long, black bill is slightly decurved. Listen for a loud, high, piercing seep uttered while the birds are perched or in flight. Perhaps due to its largeness, the Blue-throated Hummingbird’s flight seems jerky compared to other hummingbirds. It flaps and coasts along. It can fly quite swiftly over or next to streams.
For food, it relies on flower nectar, pollen, and will come to feeders. In addition, it can catch and eat beetles, flies, wasps, bugs, spiders, and daddy longlegs. The particular color of a flower does not matter as much to it as the shape. The smaller salvia mexicana utilized by most smaller hummers is of no use to the big Blue-throats. In Arizona, it is fond of penstemons, lobelias, and tree tobaccos.
The large males are avid defenders of their feeding territories. They almost always rule over smaller Violet-crowns, Black-chins, and even hummers more their own size - the Magnificents. There is a report of a male Blue-throat that flew toward and struck a Magnificent with enough force to knock it out. The male Blue-throat usually fans his tail to expose those noticeable white spots during aggressive encounters.
In Arizona, the time for breeding is relatively short. The earliest record of a returning Blue-throat in this state is for early April, but nests have been seen two weeks later. Egg records range from April 22 to July 17. In Mexico, their breeding time period is greatly extended depending on the area. Eggs have been seen in Veracruz in February, but in Mexico City the eggs are laid between late June and late September.
Female Blue-throats are very choosy about their nest sites. The nest must be completely covered from above, sheltered from both rain and sun, and close to both feeding sources and a stream. The nest is likely to be placed in vertical-walled canyons, under rock overhangs, or even under the roofs of old barns. A remarkable nest was discovered by the ornithologist Brandt in Ramsey Canyon. It was underneath a house built over the stream! Presumably, the same female had inhabited this nest for ten seasons, raising up to three broods per year there. Blue-throats are known to rebuild in the same site, year after year, until the nest is as much as a foot high. Brandt estimated that there were about 24,000 kilometers of spider silk in the one he examined.
In this species, the shape of the nest and the materials, except for spider webbing, vary considerably among individuals. The depth of the cup-shaped nest can vary from 4 to 11.5 centimeters. It can take anywhere from 15 to 30 days for the female to build it. The nest is usually covered from above by vegetation, with a nearly lateral opening. Spider silk binds together the nest which may contain oak blossom hulls, mosses, straws, or stems of weeds. Sometimes they are decorated with lichens. Whatever shape or materials each female uses to build the nest, all lay two eggs at a 48 hour interval that weigh in at about 3/4 of a gram.
In his book Hummingbirds of North America, Dan True recounts the experiences of Carroll Peabody with some Blue-throated Hummingbirds.
“During one nesting season in Ramsey Canyon, Carroll watched a male Blue-throated perch in a tree that gave him surveillance over the nests of three females. When one of the females would leave her nest to feed at a feeder, this male would speed from his perch and herd her back to her nest. One day, one of the females left her nest, and rather than go toward a feeder she hummed off into the woods. The male followed, attempting to herd her back. As soon as the two were out of sight, the other two females left their nest, flew straight to the feeder, and fed. After three days of being decoyed into the woods by one or the other of the females, the male abandoned his female-watching perch.”
Usually, males and females reside in different locations during the breeding season. The female nests close to a stream, while the male moves up higher in the mountains to feed on flowering lupines.
We’ve often seen Blue-throated Hummingbirds during the summer in all of the Arizona places mentioned in this article, but they’ve never visited us at home in Tucson. If you’ve seen them at your feeders, please let us know.