What months do hummingbirds migrate?

Hummingbirds are amazing little birds that capture the imagination with their diminutive size, incredible speed, and ability to hover in midair. These unique characteristics enable hummingbirds to engage in one of the most remarkable migration journeys in the animal kingdom. Every year, many hummingbird species undertake arduous migrations spanning thousands of miles between their breeding grounds in North America and their winter homes in Mexico, Central America, and the Caribbean.

When do hummingbirds migrate?

The timing of hummingbird migration varies by species, but typically occurs in the spring and fall each year as the birds move between their breeding and wintering grounds. Here is an overview of when most hummingbirds migrate:

• February to May – Spring migration northward to breeding grounds
• July to September – Fall migration southward to wintering grounds

The exact timing depends on the species and location. But in general, here are the months when popular hummingbird species migrate through key areas of North America:

As this table shows, spring migration occurs earlier in more southerly wintering grounds like Mexico and is later farther north as the birds travel to reach breeding areas in Canada and Alaska. The pattern reverses in fall as the birds return south at different times based on how far north they bred.

Why do hummingbirds migrate?

Hummingbirds migrate to take advantage of favorable seasonal conditions and food resources across North America. Here are some of the main factors that trigger these epic migrations:

• Breeding – Hummingbirds time their spring migration to reach northern breeding grounds when flowering plants have started blooming and insect populations have increased, providing food and nectar for breeding, nesting, and raising chicks.
• Weather – Many hummingbirds retreat south in fall to escape harsh winters and freezing temperatures where food supplies diminish.
• Food – Hummingbirds migrate to follow seasonal flower blooms and insect hatches, ensuring a constant food supply.
• Competition – Migration reduces competition for limited resources as populations spread out across different geographic areas.

Without migration, hummingbirds would be unable to survive and thrive across their widespread breeding and wintering ranges. The migration strategy allows populations to expand and access optimal habitats during the annual cycle.

What routes do hummingbirds take?

Hummingbirds follow established migration routes called “flyways” that have been optimized over thousands of years. Here are some of the main flyways used by migrating hummingbirds in North America:

• Eastern Flyway – Along the Atlantic Coast and Appalachian Mountains between Northeastern breeding areas and Southeastern wintering areas.
• Central Flyway – Through Texas and the Great Plains between the Rocky Mountains and Eastern Coast.
• Pacific Flyway – Along the Pacific Coast between the Northwest and Southwest.
• Mississippi Flyway – Along the Mississippi River Valley between the Great Lakes and Gulf of Mexico.

However, hummingbirds don’t always follow straight narrow paths. Their migration routes can be wide corridors that fan out across large areas rather than single highways in the sky. Individual birds may veer far off the beaten path or zig zag erratically during migration. But in general, they follow ancestral flyways between breeding and wintering destinations.

How do hummingbirds navigate migration?

Hummingbirds find their way over thousands of miles by using specialized navigation skills and abilities:

• Innate orientation – Hummingbirds can sense direction using the sun’s position and the earth’s magnetic field, allowing them to stay oriented even on cloudy days.
• Visual landmarks – Features like coastlines, mountains, lakes, and rivers may provide important visual cues during migration.
• Fat reserves – Hummingbirds build up fat to fuel migration, allowing nonstop flights over barriers like the Gulf of Mexico.
• Spatial memory – Young birds likely imprint on the migration route and landmarks, possessing mental maps to guide future migrations.

Remarkably, many hummingbirds migrate alone without parental guidance. Their incredible navigational abilities enable them to find their way over thousands of miles between seasonal habitats.

How long does hummingbird migration take?

The duration of hummingbird migration depends on the distance traveled and conditions encountered along the way. Here are some estimates of migration time for popular hummingbird species:

• Ruby-throated hummingbird – May complete migration in 7-10 days by flying up to 500 miles nonstop over the Gulf of Mexico.
• Rufous hummingbird – Migration may take 2-3 months with stops to rest and refuel along the way.
• Allen’s hummingbird – Breeders migrating from Mexico may reach California in 30-45 days.
• Anna’s hummingbird – Partial migration may occur over a few weeks for populations moving within the West Coast.

Although their small size enables surprisingly fast flight speeds, hummingbirds cannot complete migration in a single nonstop journey at up to 50 mph. Most species take weeks or months, stopping frequently to rest, feed, and build up energy reserves along familiar routes.

What are the longest hummingbird migrations?

A few record-holding hummingbird species make some of the longest migration journeys in the bird world relative to their tiny size:

• Rufous hummingbird – Breeds farthest north and migrates 3,900 miles from Alaska to Mexico, an immense journey for a 3 inch bird!
• Ruby-throated hummingbird – Makes a 2,000 mile round trip between the Eastern U.S. and Central America.
• Black-chinned hummingbird – Travels over 1,700 miles each way between the Western U.S. and Mexico.
• Allen’s hummingbird – Coastal populations migrate over 1,000 miles between Mexico and California.

These marathon migrations display the incredible endurance of hummingbirds. For their tiny size, they achieve some of the longest migrations in the animal kingdom. The migrations of the Rufous hummingbird, in particular, are among the most extreme relative to body size for any species.

What challenges do hummingbirds face during migration?

Hummingbirds must overcome immense obstacles during their migratory journeys, including:

• Predators – Hawks, falcons, and other birds prey on hummingbirds during vulnerable migration periods.
• Severe weather – Storms, high winds, fog, and precipitation create hazardous flying conditions.
• Food and water – Lack of nectar sources or water along migration routes can be life-threatening.
• Exhaustion – The extreme distances and durations involved push hummingbirds to their physiological limits.
• Habitat loss – Human impacts and climate change degrade stopover habitats needed to rest and refuel.

Research shows that only about 30-50% of fledgling hummingbirds survive their first southbound migration. Despite their remarkable flying abilities, hummingbirds face daunting natural challenges during these migratory journeys.

How do hummingbirds know when to migrate?

Hummingbirds appear to trigger migration based on a combination of internal programming and external cues that signal it’s time to travel north or south:

• Changing daylight – Increasing day length stimulates hormones that initiate nesting behaviors and northern movement.
• Weather and temperature – Colder temperatures may prompt southern migration to warmer climates.
• Food availability – Lack of flowers and nectar after breeding triggers southbound migration.
• Internal clock – Circannual biological rhythms and genetics guide migration timing.

Research indicates the cues that stimulate migration are complex. For example, immature hummingbirds may migrate south without ever experiencing flower decline or cold weather, guided instead by an inherited internal schedule timed with the seasons.

How are hummingbirds adapted for migration?

Hummingbirds possess remarkable evolutionary adaptations that allow them to complete their grueling seasonal migrations:

• Lightweight bodies – Weighing only 2-20 grams minimizes energy needs for flight.
• Wings – Special shoulder joints allow wings to rotate in a figure eight pattern for agility and hovering.
• Flight muscles – Up to 35% of their weight is pectoral muscles that enable sustained hovering.
• Fuels – Hummingbirds can rapidly convert sugars to energy and store fat for long flights.
• Nocturnal torpor – They save energy overnight by lowering their body temperature and heart rate.

Remarkably, hummingbird bodies and metabolisms are finely tuned for migration at their tiny scale. From rapid refueling to navigational abilities, they migrate far and fast despite weighing mere grams.

How many hummingbirds migrate each year?

It’s challenging to accurately estimate the total number of hummingbirds migrating in North America each year, but very rough estimates based on bird survey data include:

• Ruby-throated hummingbird – 35 million
• Rufous hummingbird – 5 million
• Allen’s hummingbird – 1 million
• Anna’s hummingbird – 500,000 partial migrants

Across all species combined, a conservative estimate would be around 50 million hummingbirds migrating annually. However, the actual number is difficult to quantify and may be far higher when fledglings and mortality are accounted for. Regardless of the total, hummingbirds certainly number in the millions undertaking these epic marathons each year.

Do hummingbirds migrate across the Atlantic Ocean?

There is no evidence that hummingbirds regularly cross the Atlantic Ocean during migration. All breeding hummingbirds in Eastern North America migrate south and winter within Mexico, Central America, or the Caribbean islands rather than flying across the Atlantic to South America where more hummingbird species occur.

In rare cases, individual hummingbirds have shown up in Europe after being carried off course by storms during migration. But these are one-off vagrant occurrences rather than regular transatlantic crossings between populations. Within North America, major barriers like the Gulf of Mexico pose enough difficulties for migrating hummingbirds on their normal routes.

How are hummingbirds tracked during migration?

Ornithologists use specialized techniques to study the mysteries of hummingbird migration:

• Banding – Metal bands placed on legs with unique serial numbers to identify birds later recaptured or recovered.
• Radio telemetry – Tiny transmitters attached with harnesses to track individual migration routes.
• Stable isotope analysis – Comparing isotope ratios in feathers grown at different times shows migration timing and origins.
• Citizen science – Networks of volunteer birdwatchers report hummingbird arrival and departure dates to track migration timing.

Tracking technologies and observation networks continue advancing to reveal new insights into the phenomenal marathon migrations of hummingbirds across North America.

Conclusion

The seasonal migrations of hummingbirds are one of the most astonishing phenomena in the natural world. These diminutive birds undertake arduous journeys spanning thousands of miles between breeding and wintering habitats. Their migrations are tuned with incredible precision to sync with flower blooming, insect hatches, and other phenology to ensure abundant food resources along their routes. Although challenged by predators, weather, and grueling distances, hummingbirds are exquisitely adapted with specialized physiology and navigation abilities that enable their extraordinary marathon migrations to continue year after year.