The ruby-throated hummingbird (Archilochus colubris) is the most common and widely distributed hummingbird in North America. This tiny bird, measuring only 3-4 inches long, weighs about the same as a penny but migrates immense distances each year.
When does the ruby-throated hummingbird migrate?
Ruby-throated hummingbirds begin migrating from their breeding grounds as early as July. The peak migration occurs in mid-August through early September as the birds travel south to their overwintering grounds in Mexico and Central America. Not all individuals migrate at the same time, as some summer residents linger into October or November before heading south. By late October, nearly all ruby-throats have departed their breeding territories in the United States and southern Canada.
In spring, the return migration starts in February as the earliest individuals begin winging their way north. The peak of spring migration happens in mid-April to early May. The males tend to arrive at the breeding grounds first, followed by the females several days to a week later.
Where does the ruby-throated hummingbird migrate?
The ruby-throated hummingbird has one of the most extensive migration ranges of any North American bird. It breeds across much of the eastern United States and southern Canada, north to Nova Scotia and as far west as the Dakotas, Nebraska, Oklahoma and Texas. Some vagrants may reach the western United States and even southern Alaska.
In winter, this species occupies southern Mexico and Central America from southern Veracruz to Panama. The majority of the population winters in Mexico and Guatemala. very small numbers reach Belize, Honduras, Nicaragua and Costa Rica.
So this tiny bird migrates anywhere from 500 miles to over 2,000 miles between its breeding and wintering grounds each year. Some ruby-throats that breed in southern Canada may log 4,000 miles on their round-trip journeys.
What is the migration route of the ruby-throated hummingbird?
Ruby-throated hummingbirds follow different migration pathways depending on their breeding origins, but there are some general routes used by much of the population:
- Birds breeding east of the Appalachian Mountains generally take an overland route across the southeastern U.S. before crossing the Gulf of Mexico to the Yucatan Peninsula.
- Birds from breeding areas near and west of the Appalachians tend to migrate southwest to the Gulf Coast before flying across the Gulf of Mexico.
- Some birds originating from the far western areas of the breeding range may migrate west of the Rocky Mountains before angling south into Mexico.
Once they reach Mexico and Central America, the hummingbirds spread out across the tropical wintering range from Veracruz to Panama.
Spring migration routes
In spring, ruby-throated hummingbirds follow the same general pathways in reverse as they return to their breeding grounds. Those wintering on the Yucatan Peninsula cross the Gulf of Mexico and fan out across the eastern U.S. Birds wintering from Veracruz to Nicaragua migrate north through Mexico to reach breeding areas in the southwest and central U.S.
How does the ruby-throated hummingbird migrate?
The ruby-throated hummingbird makes its marathon migrations solo. They do not migrate in flocks like many bird species. Each individual finds its own way between the seasons through innate navigation skills and spatial memory.
These tiny birds can fly an astonishing 25-30 miles per hour. They have high metabolisms and must feed frequently to fuel their flight. During migration, they break up their journey by stopping to rest and refuel at flowers, feeders and fruiting trees along the way. They may fly 6-12 hours at a stretch before needing to rest and eat.
Migrating hummingbirds are opportunistic in their stopover locations. Some habitats, like areas along coastlines, large lakes, and mountain ridges, may concentrate the migrants during travel. But they will stop wherever food can be found along their route.
Ruby-throats migrate across the Gulf of Mexico, a 500 mile open water crossing, in a single overnight flight of up to 23 hours duration. They gain fat reserves by hyperphagia, gorging on food before starting the water crossing. This provides extra energy to power their flight.
Some ruby-throats actually “island hop” across the Gulf, stopping to rest on oil rigs or ships mid-crossing before resuming their journey. Banding and tracking studies have shown the birds can end up 300 miles or more off their normal migration route over the Gulf.
What challenges do ruby-throated hummingbirds face during migration?
Migration is the most perilous time in a ruby-throated hummingbird’s life. The long distance travel to traverse inhospitable habitat like deserts and open water, combined with the metabolic demands of flight, result in high mortality rates during migration. Estimates indicate that 50-70% of juveniles and 30-40% of adult hummingbirds die on migration from starvation, predation, collisions and bad weather.
Some specific threats faced by migrating ruby-throated hummingbirds include:
- starvation – Lack of food at stopover sites forces the birds to burn critical fat stores needed to complete their journey.
- extreme weather – Cold fronts or storms may force exhausted birds down early during overwater crossings, causing them to drown or knocking them off course.
- habitat loss – Fewer natural stopover habitats make finding food more difficult during the journey.
- light pollution – Nocturnal migrants can become disoriented by artificial light pollution, wasting energy and increasing mortality.
- buildings and towers – Collisions with human-made structures are a major hazard, especially for juveniles on their first migration.
- predators – Migrating ruby-throats are vulnerable to predators like falcons, shrikes, and bullfrogs as they stop to refuel.
How is the ruby-throated hummingbird migration changing?
There is evidence that ruby-throated hummingbirds are shifting their migration patterns in response to climate change and altered habitat conditions. Some observed changes include:
- Earlier spring arrival and later fall departure dates as warming temperatures allow the birds to migrate earlier and remain later in the season.
- Shifts in migration routes to follow flower availability as bloom cycles change with warming.
- Greater reliance on backyard feeders as natural food sources decline.
- Expanding wintering range northward in the U.S. as temperatures warm.
Researchers are investigating how ruby-throated hummingbird migration patterns may continue to shift and the implications for the species. Maintaining habitat corridors and food sources along migration routes will be important for successful migration in the future as conditions change.
Key Facts About Ruby-Throated Hummingbird Migration
Here are some key facts to summarize the ruby-throated hummingbird’s epic migration:
| Migration Distance | 500 – 4000 miles one-way |
|---|---|
| Breeding Range | Eastern U.S. and southern Canada |
| Winter Range | Southern Mexico to Panama |
| Migration Start | July – November (southbound) February – May (northbound) |
| Route | Across Gulf of Mexico, through Mexico and Central America |
| Speed | 25-30 mph, covering hundreds of miles in multiple long flights |
| Hazards | Exhaustion, starvation, predators, bad weather, buildings/towers |
Conclusion
The ruby-throated hummingbird is a true marvel of nature for undertaking an strenuous annual migration up to 4,000 miles round trip. These tiny birds traverse huge distances, flying up to 500 miles nonstop over the Gulf of Mexico to complete their migratory journey between their breeding and wintering grounds. While migrating, ruby-throated hummingbirds face many threats and challenges during their journey, including habitat loss, extreme weather, predators, and human-made obstacles. Their migrations may take on even greater complexity as climate change alters migration patterns and timing. Increased conservation measures focused on protecting habitat corridors and food sources will support the ruby-throated hummingbird’s remarkable migratory feat into the future.
