Hummingbirds are amazing little birds that bring joy to backyard bird watchers across Pennsylvania each summer. Their lightning-fast wings beat up to 80 times per second, allowing them to hover and fly backwards with ease. The bright, iridescent colors of males dazzle the eye as they aggressively defend their turf. Yet despite their feisty nature, hummingbirds are fragile creatures that migrate vast distances each year between their summer and winter homes.
When do hummingbirds arrive in Pennsylvania?
Most hummingbirds arrive in Pennsylvania in early May and remain until late September or early October. The timing depends on the species:
- Ruby-throated Hummingbirds are the most common and widespread species in Pennsylvania. They arrive in early May and most depart by late September.
- Rufous Hummingbirds start arriving in mid-August and remain until mid-October. They migrate from the Pacific Northwest to winter along the Gulf Coast.
- Calliope Hummingbirds pass through Pennsylvania on their way south in mid-August. They breed in the northwestern U.S. and Canada.
Arrival times can vary slightly from year to year depending on weather patterns and food availability along their migration routes. But most hummingbirds reach Pennsylvania in early May – just in time to take advantage of the spring wildflower bloom.
What triggers hummingbirds to migrate north in spring?
Increasing daylight hours and warming temperatures trigger hummingbirds to begin their northward migration in early spring. Other factors influencing migration timing include:
- Food availability – Abundant flowers and insects in more northern regions provide the fuel for migration and breeding.
- Hormone changes – Changes in hormone levels, stimulated by increasing daylight, cause physiological changes needed for migration and reproduction.
- Genetics – Migration timing is innate and programmed genetically to ensure arrival on breeding grounds at optimal times.
By paying close attention to all these cues, hummingbirds know when to travel north to take advantage of the seasonal bloom of flowering plants. Their intricate internal calendar and compass keep them on track to reach Pennsylvania in early May.
What is the spring migration route for hummingbirds coming to Pennsylvania?
Ruby-throated Hummingbirds follow a circuitous spring migration route from Mexico and Central America back to the eastern United States and Canada. Their journey northward progresses as blooming plants provide nectar fuel along the way:
- February-March: Depart winter grounds in Mexico and Central America
- March-April: Pause along the Gulf Coast as they await blooms farther north
- April: Move up the Mississippi River valley as flowers come into bloom
- Late April: Arrive in the southern Appalachian Mountains
- Early May: Reach Pennsylvania and breeding grounds farther north
This stepping stone route ensures they have adequate food supplies along the way to replenish their energy. Pennsylvania’s early spring flowers provide an important refueling stop before the final leg of their journey to breeding areas in Canada.
Why do hummingbirds migrate south for the winter?
Hummingbirds have an innate drive to migrate south in late summer and fall. There are several advantages to spending the winter in Mexico or Central America:
- Food availability – There are not enough flowering plants and nectar sources in Pennsylvania to sustain hummingbirds through the winter.
- Energy conservation – The warmer climate allows hummingbirds to reduce their metabolic rate and conserve energy.
- Predator avoidance – Fewer predators, like hawk and falcons, winter in the tropics.
Migrating south in fall helps hummingbirds survive the scarce winter months and live to breed again. Their internal programming initiates restlessness, extra feeding, and fat storage in preparation for the long journey back to their wintering grounds.
What triggers fall migration in hummingbirds?
Shortening daylight hours, cool nights, and dwindling food supplies provide the signals that nudge hummingbirds to begin migrating south in late summer. Here are some specific triggers:
- Declining daylight – Hummingbirds sense the shorter days and know winter is approaching.
- Lower temperatures – Cool nights prompt hummingbirds to put on fat for insulation and migration.
- Fewer flowers – The end of the blooming season means less natural nectar availability.
- Hormones – Changes in hormone levels initiate restlessness, extra feeding, and fat storage.
These cues initiate both physiological changes and behavioral changes that get hummingbirds ready for their long journey back to the tropics. By late September, most hummingbirds have departed Pennsylvania for their winter habitat.
What is the fall migration route for hummingbirds leaving Pennsylvania?
In August and September, Ruby-throated Hummingbirds prepare for their return migration by feeding extensively and storing fat. By late September, most have departed Pennsylvania on their southbound journey:
- Late September: Begin migrating south through the Appalachians
- Early October: Fly along the Gulf Coast of Texas and Mexico
- Mid-October: Cross the Gulf of Mexico to arrive in Mexico and Central America
- November-March: Spend the winter in tropical forests and scrublands
This direct southbound path takes them back to familiar wintering sites with plentiful flowers and shelter. Their internal navigation keeps them oriented properly throughout the long flight over the Gulf of Mexico.
What are the longest migration routes for hummingbirds that visit Pennsylvania?
While Ruby-throated Hummingbirds may log 4,000 miles roundtrip on their annual migration, some vagrants visiting Pennsylvania rocket that distance. Here are a few record-setting hummingbird migrations:
| Species | Breeding Region | Migration Route | Miles (one-way) |
|---|---|---|---|
| Rufous Hummingbird | Pacific Northwest | To the Gulf Coast | 3,900 |
| Calliope Hummingbird | Western North America | Across the Great Plains to Florida | 4,600 |
| Allen’s Hummingbird | California | Across desert Southwest to Mexico | 3,000 |
These tiny travelers demonstrate incredible endurance flying thousands of miles over mountains and deserts. Seeing them in Pennsylvania is a rare treat for birdwatchers.
How do hummingbirds navigate their biannual migrations?
Hummingbirds find their way on migration using a combination of innate abilities:
- Compass sense – They can detect magnetic fields to determine direction.
- Star navigation – On clear nights, patterns of stars help guide their path.
- Landscape cues – They follow coastlines, mountains, rivers and vegetation patterns.
- Circadian rhythms – Their internal clock helps maintain orientation.
- Smell and memory – They follow remembered landmarks and odors.
Remarkably, many hummingbirds return to the exact same breeding and wintering sites each year. Their navigation skills are finely tuned to the demands of migration.
How fast and far do hummingbirds fly on migration?
Hummingbirds are built for speed and endurance while traveling:
- Speed – Cruising speed of 20-30 mph; up to 50 mph in courtship dives
- Distance – Capable of nonstop flights of 500 miles or more in one day
- Duration – May travel 12-14 hours on migration days
- Heartrate – Over 500 beats per minute during flight
- Wings – Flapping up to 80 times per second
Their specialized body and physiological adaptations allow these tiny birds to achieve record-setting flight performances. The Ruby-throated Hummingbird makes the 500 mile, 18-20 hour Gulf crossing in a single, nonstop push.
How do hummingbirds know when to start migration?
Hummingbirds rely on internal programming and external cues to determine when to migrate each season. Here are some key signals:
| Spring Migration | Fall Migration |
|---|---|
| – Increasing daylight hours | – Decreasing daylight hours |
| – Warming temperatures | – Cooling temperatures |
| – Changes in hormones | – Changes in hormones |
| – Flower/food availability | – Decline in flowers/food |
| – Genetic timing prompts | – Genetic timing prompts |
Their internal calendar and ability to interpret seasonal cues gets their migration timing just right. Heading south too early risks a lack of flowers along the way. Staying too long may lead to starvation or cold exposure.
Conclusion
Hummingbirds undertake one of the most arduous migrations in the animal kingdom despite their tiny size. Their persistence and navigational skills are impressive and finely tuned. While hummers only grace Pennsylvania with their beauty briefly each year, backyard birders eagerly await their return. The arrival of hummingbirds is a sure sign warm seasons have returned to the state – at least until these magical birds once again embark on their extraordinary migratory journey.
