For the Birds – Ruby-throated Hummingbird

The Ruby-throated Hummingbird has to be one of most eagerly anticipated birds among our migratory breeding birds. The acrobatic flight of hummingbirds, their iridescent colors and their small size endear hummingbirds to many people.

The hummingbird family is one of the largest of the birds with 328 recognized species. Hummingbirds are birds of the New World with the majority found in the tropics of Central and South America. In North America, only about 20 species occur regularly and only one, the Ruby-throated Hummingbird, breeds in eastern North America.

The Ruby-throated Hummingbird is one of the smaller hummingbirds. A typical one weighs a little more than 3 grams, about the weight of a penny. The smallest hummingbirds are the Bee Hummingbird from Cuba and the Reddish Hermit from Brazil and Guyana, which weigh only 2 grams. On the larger side, the South America sicklebills and the Sword-billed Hummingbird weigh 12-14 grams, a little more than a chickadee. The Sword-billed Hummingbird has the longest bill of any hummingbird at an astonishing five inches! The largest of all hummingbirds is the appropriately named Giant Hummingbird, which tops the scales at 21 g.

Ruby-throated Hummingbirds spend the winter between southern Mexico and western Panama. In migration, some individuals undertake a non-stop migration of 1000 miles across the Gulf of Mexico. The birds have to put on extra fat to fuel this expensive flight. Feeding on nectar and insects, a Ruby-throated Hummingbird will double its weight before it departs across the Gulf of Mexico.

Recent observations indicate that some Ruby-throated Hummingbirds prefer to migrate along the eastern coast of Mexico to reach the United States, a longer but perhaps less demanding migration.

To increase our understanding of Ruby-throated Hummingbird migration, an international volunteer project has begun called Operation RubyThroat. The project is designed primarily for K-12 teachers and their students in the countries of Central America and North America. You can find information on Operation RubyThroat at their web site: http://www.rubythroat.org/

Once in the United States, Ruby-throated Hummingbirds disperse widely. The breeding range extends from eastern Texas along the Gulf Coast to Florida and north in the east to Nova Scotia, New Brunswick and Labrador and west to Minnesota, then spreading westward in the Canadian prairie provinces, stopping just shy of British Columbia. Their breeding range is the largest of any hummingbird breeding in North America.

Hummingbirds are specialized to feed on nectar. A number of plants and hummingbirds have evolved mutualistic relationships. These plants produce sugar-rich nectar, which attracts hummingbirds. As the hummingbirds feed on the flower, pollen attaches to the hummingbird’s head and bill. When the hummingbird visits another flower, some of the pollen it is carried is transferred to the female part of the flower and fertilization is assured. Some plants therefore “pay” hummingbirds in nectar in return for pollination services.

One species that seems particularly adapted for pollination by Ruby-throated Hummingbirds is the trumpet creeper, a woodland vine. Studies have shown that Ruby-throated Hummingbirds deposited ten times as much pollen as other pollinators (bumblebees and honeybees).

Most long, tubular flowers are attractive to hummingbirds. Bee balm is particularly recommended. Of course, a hummingbird feeder is an easy way to attract hummingbirds as well. Choose a feeder with a wide mouth to make cleaning easy. You can buy so-called hummingbird food to dissolve in water. On the other hand, you can save some money and make your own. Just mix four parts of water to one part of table sugar and bring to a boil. When the sugar dissolves, cool and then fill your feeder. You can store the excess in your refrigerator for a couple of weeks.

Keep an eye on your feeder. Particularly in warmer weather, fungi grow in the feeder. You should wash your feeders regularly; easy to clean feeders will make this task a quick one.

Nest building in Ruby-throated Hummingbirds is done only by the female and takes between 6 and 9 days. The base of the nest is made of thistle and dandelion down. The base is saddled along a branch and is fastened with spider webs. The female stamps down the plant down to make a firm floor. White plant down and bud scales make up the side of the nest. The female uses a figure-8 motion to lace the plant material together. The outside of the nest is adorned with lichens, making a well-camouflaged nest.

Two eggs are laid and hatch 12-14 days later. The female does all the feeding of the young. The young are feed nectar at first with supplements of insects as they grow larger. The young fledge 18-20 days after hatching.

[Originally published on May 1, 2009]