Hummingbirds are some of the most amazing migrators in the animal kingdom. These tiny birds, often weighing less than an ounce, make migratory journeys of thousands of miles every year between their summer breeding grounds in North America and their overwintering grounds in Mexico and Central America. Their migrations fascinate both amateur birdwatchers and professional ornithologists alike. In recent years, technology has opened up new possibilities for studying hummingbird movements and behavior during migration.
How do hummingbirds navigate their migrations?
Hummingbirds migrate alone, not in flocks, so they don’t rely on social cues to find their way. Instead, research suggests they navigate using a combination of innate compass senses, visual landmarks, and environmental cues. Experiments show that hummingbirds can sense the Earth’s magnetic field to help keep them on course during migrations. They also likely use the position of the sun and patterns of polarized light in the sky as navigational guides. Hummingbirds learn landmarks like mountains, coastlines, and rivers to follow during migrations. Shifting winds and weather patterns also provide environmental information to migrating hummingbirds.
| Navigation Method | Description |
|---|---|
| Compass senses | Ability to detect Earth’s magnetic fields and orient using them |
| Visual landmarks | Use of mountains, rivers, coastlines, etc. to navigate |
| Environmental cues | Use of sun position, polarized light, winds, weather patterns |
Hummingbirds’ navigational abilities are impressive considering their small size. Scientists continue to study how these tiny birds make their way over thousands of miles with such accuracy.
What routes do hummingbirds take?
The majority of hummingbirds that summer in the United States and Canada migrate south to Mexico and Central America for the winter. Most travel across the Gulf of Mexico, an 18-24 hour nonstop flight over open water for a hummingbird. However, some hummingbirds migrate over land, taking routes through Mexico and along the U.S. Pacific Coast.
Here are the major migration routes followed by some common hummingbird species:
- Ruby-throated Hummingbird – Across Gulf of Mexico to southern Mexico and Central America
- Rufous Hummingbird – Down U.S. Pacific Coast to Mexico
- Allen’s Hummingbird – Across Gulf of California to Mexico
- Costa’s Hummingbird – Down Baja California peninsula to western Mexico
- Broad-tailed Hummingbird – Through western U.S. and Mexico to southern Mexico/Guatemala
By banding hummingbirds and retrieving information from recovered bands, scientists have mapped out these major flyways. However, much remains unknown about the specific routes individual hummingbirds follow and how they find stopover sites to rest and refuel along the way.
When do hummingbirds migrate?
Most hummingbirds migrate in the spring and fall to coincide with flower availability and other food resources. Here are the typical migration windows:
| Season | Timing |
|---|---|
| Spring | February – May |
| Fall | July – October |
Exact timing varies by species and depends on factors like weather and food resources. Males often migrate earlier in spring to secure the best breeding territories. Females and young birds follow weeks or even months later. Fall migration typically starts earlier for adult males and older juveniles.
How long do hummingbirds migrate for?
One-way migration journeys for hummingbirds can total thousands of miles:
- Ruby-throated Hummingbird – Up to 2,000 miles
- Rufous Hummingbird – Up to 3,000 miles
- Allen’s Hummingbird – Up to 1,000 miles
- Broad-tailed Hummingbird – Up to 2,500 miles
However, most hummingbirds take months to complete their full migrations. They stop to rest and feed many times at flowers and feeders along the migration route, staying for a few days to a few weeks to fuel up before moving on. Some research estimates hummingbirds may spend only 10% of their migration time actually flying between stops.
Faster, stronger fliers like adult males make the complete one-way migration in a few weeks. Slower juveniles and females may take two months or longer to travel the same distance. Poor weather like storms can also delay migrations and extend travel times.
How fast and high do hummingbirds fly during migration?
Hummingbirds are capable of incredible flying speeds during migration, likely covering up to 35 miles per hour for some periods. However, they cannot maintain these top speeds over long distances. Their average migration travel speed is estimated between 12-25 miles per hour.
Hummingbirds migrate at lower altitudes during travel over land. But during long ocean crossings like the Gulf of Mexico, they move higher up to take advantage of favorable winds. Some research using weather radar tracking suggests hummingbirds may ascend to altitudes up to 2 miles above sea level during these ocean flights.
| Migration Phase | Estimated Speed | Estimated Altitude |
|---|---|---|
| Over land | 12-25 mph | Surface to 5,000 ft |
| Over ocean | 25-35 mph | Up to 2 miles (10,500 ft) |
The energetic demands of these high speeds and altitudes require hummingbirds to be in peak physical condition before migrating. They hyperfeed, nearly doubling their body mass, in the weeks leading up to migration to store enough fat reserves to fuel these extreme flights.
How is technology being used to study hummingbird migration?
Hummingbird banding and recovery has provided valuable migration data for decades. But new tracking technologies are revolutionizing scientists’ ability to follow individual birds throughout their journeys. Here are some key technologies advancing hummingbird migration research:
- GPS tags – Tiny GPS devices placed on a hummingbird can report the bird’s precise location multiple times per day as it migrates. However, these are still limited by battery life and hummingbird size.
- Geolocators – Light level geolocators allow estimating a hummingbird’s location. They can record up to a year of travel but have less precision than GPS.
- Stable isotope analysis – Measuring forms of elements like hydrogen in hummingbird tissues can reveal the geographic areas a bird traveled through during migration.
- Weather surveillance radar – Networks like the U.S. NEXRAD radar have detected and tracked large-scale hummingbird movements during migration.
Citizen science initiatives also engage public participation in reporting hummingbird sightings and band encounters to contribute data on migration timing and routes. As tracking methods continue improving, scientists gain more insights into the detailed migration behavior of individual hummingbirds across their full annual journeys.
Could cell phone apps supplement migration research?
While not yet reality, experts speculate future cell phone apps could utilize the sensing and networking capabilities of phones to crowdsource valuable information on hummingbird migrations. Some possibilities include:
- Users photographing and reporting hummingbird sightings through an app during migration seasons to map out species ranges and timing
- Using phone cameras to capture unique iridescent patterns on hummingbirds as visual tags to identify individuals
- App allowing phones to detect high-pitched hummingbird chirps and report frequency and location data
- Integrating user-reported sightings from thousands of phones along migration routes to supplement radar tracking
For any app-collected data to be useful for research, though, the information would need careful verification and quality control to ensure accuracy. Such an app would depend on widespread engagement and participation from the public. While promising, the practical challenges of harnessing cell phone capabilities to gather reliable migration data likely means this technology’s time has yet to come.
What threats do hummingbirds face during migration?
Migrating hummingbirds face many threats and obstacles on their journeys, including:
- Lack of food/habitat – Fewer flowers and feeders along migration routes make refueling more difficult
- Extreme weather – Storms, high winds, and precipitationcreate dangerous flying conditions
- Predators – Hawks, falcons, and other birds prey on hummingbirds
- Collisions – Windows, towers, vehicles, and other structures arecollision hazards
- Light pollution – Night lights can disorient migratinghummingbirds
Research also indicates climate change may negatively impact migration patterns and food availability. Citizen participation in providing nectar feeders, removing collisions hazards, and turning off unnecessary lights during migration can help counter migration threats.
How can I observe hummingbird migration?
Here are tips for witnessing hummingbird migration magic in your own backyard:
- Keep feeders clean, nectar fresh, and foliage around feeders minimized for easy access
- Choose red feeders and hang at optimal height to attract migrators
- Plant native flowers and shrubs that provide nectar and insects
- Post hummingbird sightings to community science sites like Journey North or eBird
- Photograph unique beak shapes, plumage details, and band numbers to identify birds
- Track activity and empty/refill feeders more often during peak migration windows
Focus observations in May and September when most hummingbirds pass through. With some diligence, fascinating insights into hummingbird migrations are within anyone’s reach.
Conclusion
While much remains unknown about their navigation methods and full migration cycles, technological advances are unlocking more hummingbird secrets than ever before. Miniaturized GPS devices, machine learning analysis of radar data, and crowdsourced citizen science initiatives promise an exciting future for understanding these aerial marvels. As research progresses, perhaps one day phone apps may open new crowdsourcing opportunities to enhance hummingbird migration tracking. For now, anyone can still marvel at the passage of these tiny travelers in their own backyards and contribute sightings to our collective knowledge.
