Issue 11
Hummingbirds
April 2011
As spring progresses across the United States and Canada, birders in the Southeast have begun to notice the buzzy flight of ruby-throated hummingbirds (Archilochus colubris) around their backyards. These tiny jewel-like birds are on the move to find breeding grounds to nest and raise their young.
The only hummingbird species that breeds in eastern North America, ruby-throateds spend the winter in Mexico and Central America as far south as northern Panama. Hummingbirds pack on the winter weight to make their long journey north, almost doubling their mass to make it back for the season. On spring nights, many thousands of tiny birds, each weighing less than a nickel, are furiously beating their wings to catch prevailing winds across the Gulf of Mexico. Once ashore, their priority is to find plants and insects to fuel up and rest for the next leg of their journey.
The website hummingbirds.net has a migration map that records sightings of ruby-throated hummingbirds across the USA and Canada. Check back to see the progress in your area and use it to record your sightings.
FEATHERWEIGHTS
Ruby-throated Hummingbird, male
The ruby-throated hummingbird (Archilochus colubris) weighs on average about 3.8 grams (less than a nickel). That’s average for most species of hummingbirds in North America.
Calliope Hummingbird, male
The calliope hummingbird (Stellula calliope), our smallest hummingbird, weighs in at just 2.7 grams (slightly more than a penny).
Why do they make such a perilous, almost heroic trip? No one really knows for sure, but we do know that to successfully reproduce, hummingbirds need a good supply of insects, flower nectar, and suitable habitat to raise their young. Hummingbirds have evolved as a type of avian specialist. Their extremely long tongues can reach deep into flowers to sip nectar. This food source gives them sugary energy in the form of carbohydrates to fly around and catch tiny insects on the wing.
Hummingbirds also adroitly pluck spiders from their webs and then keep on moving to the next meal. And they really need to eat. Ruby-throateds beat their wings about 40–80 times per second. Their heart beats from 250 beats per minute at rest to 1200 beats per minute in flight. Their normal speed on the wing is about 30 mph and their top speed in a dive is clocked in at 63 mph.
Male hummingbirds are fiercely territorial and will chase away other hummingbirds that enter their nesting area. Hummingbirds construct cup-like nests out of dried grasses and spider webs and attach lichen to the outside to camouflage it from potential predators. Ruby-throateds have a clutch of two eggs and they incubate them for about two weeks tucked under the parent’s chest and abdomen feathers. When the eggs hatch, the male and female tirelessly take turns guarding and feeding the young until they leave the nest just two to three weeks later. Ruby-throated adults may have two clutches per season and the young will migrate south in the fall and the cycle begins again.
Celebrate the diversity of hummingbirds native to the continental United States and Canada with Sibley’s Hummingbirds of North America. This 18 × 24 inch poster includes 18 species in 88 illustrations from the Sibley Guide to Birds of North America. Birds are shown in multiple poses, angles, and life stages to aid in identification. Each species is reproduced in relative scale to show the size differences between species. It’s the perfect bird poster to welcome back the tiny travelers to our backyards and gardens.
