Hummingbird Migration

All about hummingbird migration:

Goose-riding	Refueling
All By Myself	Nectar Corridors
Longest Haul	Migration Maps
Non-stop Flights

Goose-riding

First things first. Hummingbirds do not ride on the backs of geese. We understand why caveman may have believed this (with all due respect to cavemen), but why does this myth still persist today?

Just think of the implications:

Most geese winter in the southern U.S. That would mean all our hummingbirds would have to get off and transfer to the duck-express in order to travel further south, since most of our breeding hummingbirds winter in Mexico and Central America.

Geese don't migrate early enough - they're still way north in the Arctic when hummers should be already south, sipping tropical nectar cocktails. They would turn into hummer-sicles waiting on geese!

Assuming there are more hummingbirds than geese, each goose would have to carry many hummingbirds. How would the hummers sort out who gets shot-gun?

There would be numerous observations reported of geese spinning circles like dogs trying to get fleas off their backs. "What's back there?"

With all those extra grams of weight from the hummers on their backs, goose fuel mileage would decrease, the cost of gas would go up, and hybrids in the goose population would soon abound?!

Geese don't stop-over in patches of flowering plants during migration, so what's a hummingbird to eat? Even when you're riding in a car, you still get hungry. Hummingbird C-stores would be popping-up everywhere.

Now that's all cleared up, here are some facts:

All By Myself

It's quite amazing, but hummingbirds do migrate by themselves, under their own power, and as solitary migrants, not in flocks.

Hummingbirds migrate because it is an innate, genetic instinct. Factors such as weather, length of daylight, & fat accumulation stimulate migration.

Migration routes and timing vary from species to species and even population to population. Most of the more than 300 hummingbird species living in the tropics do not migrate because of the constant warm temperatures and abundant food supplies.

But most of the species that breed north of Mexico in the U.S. & Canada do migrate to separate wintering grounds. There are some exceptions of populations that remain along the Pacific Coast and the Mexican border where conditions are suitable year-round.

Longest Haul

Rufous Hummingbirds (Selasphorus rufus) make the longest migration of any of the Trochilidae (Hummingbird Family) and, in proportion to size, one of the longest bird migrations.

It breeds as far north as Alaska and winters in Central America, a distance of ~2700 miles. This is is equivalent to 49,000,000 body lengths. This is the longest migration of any bird in terms of body length.

Non-stop Flights

Many Ruby-throated Hummingbirds travel more than 2,000 miles to go from Panama to their breeding destination in Canada. People wondered how the Ruby-throat could cross the Gulf of Mexico without stopping to refuel, a minimum trip of ~500 miles (the shortest distance across the Gulf).

To answer this question, R.C. Lasiewski conducted a

study in 1962, The energetics of migrating hummingbirds (Condor 64:324). As a result of his experiments with hovering hummingbirds in metabolic chambers, Lasiewski concluded that a male Ruby-throated hummingbird, weighing about 4.5 g, of which 2 g was fat, could fly nonstop for 26 hours, consuming the fat at the rate of 0.69 calories per hour.

At an average speed of 25 mph per hour (40 km/hour), the bird's flying range would be about 606 miles (975 km) - easily enough to span the Gulf of Mexico.

In a more recent study, Calder and Jones (1989) using arrival and departure masses and rates of gain from Rufous Hummingbird banding data, determined that a 747 mile (1,202 km) flight of a Rufous appears to have been possible. At an airspeed of 43 km/h, the Rufous was able to travel 747 miles in 28 hours or two 373-mi (601 km) legs in 14-hour days apiece, depending on unknowns of tailwinds & successful refueling points.

Therefore, on its 2,700-mile journey from Mexico to Alaska, a Rufous Hummingbird will stop at least 4 times to refuel.

Refueling

Compared to other birds, the metabolic rates of hummingbirds are extremely high. For example, a 4-gram hummingbird has a basal metabolic rate of 1,400 calories per kilogram. Compare that to a 121 gram mourning dove which has a rate of 127 calories per kilogram.

According to Bill Calder, a University of Arizona hummingbird expert, it takes about a week for a migrating hummingbird to replace the protein and fat metabolized on a completed flight segment.

So for the Rufous that makes at least 4 refueling stops from Mexico to Alaska, their journey may take anywhere from 4-8 weeks. Refueling stops may even be longer than 2 weeks, depending on weather, headwinds, and nectar availability.

Nectar Corridors

The breeding season & initiation of hummingbird migration is closely tied to the flowering seasons of their major nectar sources. In temperate latitudes, this corresponds to the northern and southern springs when flowering plants begin to bloom.

The rigors of hummingbird migration coupled with high metabolic rates requires these tiny birds to refuel often when traveling to their breeding grounds. So when they stumble upon your feeder along the way, it's like they've landed at the all-you-can-eat buffet, for free! (unless there's aggressive competition).

In addition, nectar corridors, or migration routes abundant with flowering resources, are vital to hummingbird survival. Tens of thousands of hummingbirds migrate through these corridors on their way north & south to refuel.

Habitat loss, degradation, and fragmentation may affect hummingbirds nectar corridors due to loss of native flowering plants. The Migratory Pollinators Program explains this in more detail. See Threats and Conservation of Humming Bird Migration.

Hummingbird Migration Maps

Ruby-throated Hummingbird Migration Map

You can use these links to report your hummingbird migration observations as well as see other reports as the migration moves across the U.S. and into Canada.

Rufous Hummingbird Migration Map
Current maps for Rufous migration observations.

Here's and award winning, not-to-miss bird migration video, Winged Migration. Witness as five film crews follow a rich variety of bird migrations through 40 countries and each of the seven continents.