As autumn approaches each year, many backyard birdwatchers notice a distinct lack of hummingbirds and orioles at their feeders. The busy buzz and flashes of color from these migratory birds dissipate, leaving us to wonder: where have all the hummingbirds and orioles gone?
Why do hummingbirds and orioles migrate?
Hummingbirds and orioles migrate in order to survive the winter. These small birds consume a huge amount of calories to power their supercharged metabolisms. Hummingbirds visiting feeders can drink up to twice their body weight in nectar each day! Orioles rely on fruit and insects that simply aren’t available through frigid northern winters. So around August to September each year, hummingbirds and orioles take off on a strenuous journey of thousands of miles to reach warm southern climates rich in food.
Some key reasons these birds migrate:
- Lack of food – Flowers, nectar, fruits, and insects become much more scarce in northern climates once winter hits.
- Lack of shelter – Hummingbirds and orioles build nests in trees and shrubs which lose their leaves in winter, leaving them exposed.
- Lack of warm weather – Tiny hummingbirds and orioles have high metabolisms and struggle to maintain their body heat in freezing temperatures.
By traveling south, they can continue feasting and stay comfortable year-round rather than tough it out through winter.
Where do hummingbirds go in winter?
Most ruby-throated hummingbirds east of the Mississippi River migrate south to Mexico, Central America, and Florida. Some head to Caribbean islands as well. Western hummingbirds such as rufous hummingbirds often migrate to Mexico or even as far south as Panama.
Here are some top wintering grounds for hummingbirds:
- Mexico
- Costa Rica
- Panama
- Florida
- The Caribbean – Jamaica, Cuba, Puerto Rico
In their winter destinations, hummingbirds flock to tropical forests, gardens, and meadows that supply the nectar and small insects they feed on. Some hummingbirds even spend winters high in the Andes Mountains, enjoying milder temperatures and blooming flowers.
Where do orioles go in winter?
Like hummingbirds, Oriole species that breed in the USA and Canada head to the tropics for winter. Baltimore and orchard orioles generally migrate to Central America and northern South America.
Top wintering grounds for orioles include:
- Southern Mexico
- Panama
- Colombia
- Venezuela
Some orchard orioles only migrate as far south as Florida. In tropical forests and jungle canopies, orioles enjoy plentiful fruit and insects during winter.
What triggers hummingbirds and orioles to migrate?
What signals these small birds to pack their bags and head south? Changing seasonal conditions trigger certain behavior and physiological changes that initiate migration. Here are key factors:
- Day length – As days shorten in late summer, hummingbirds and orioles instinctively know to prepare for migration.
- Hormones – Changes in hormones including corticosterone influence hyperphagia (increased appetite to store fat), restlessness, and orientation for migration.
- Food availability – Declines in flower nectar, fruit, and insects reinforce it’s time to move on.
- Weather – Cooler temperatures and winds shifting to the north provide obvious clues that winter is coming.
Young birds hatched that same summer make the full migratory journey guided by their instincts and internal cues rather than experience. Their first trip south is a real feat of nature!
How do they know where to migrate to each year?
Hummingbirds and orioles find their way to the same wintering sites year after year through these natural navigational aids:
- Instinct – Hummingbirds and orioles rely strongly on inherited instincts to indicate the appropriate migration direction, routes, and destinations.
- Landmarks – On their first journey, birds use major physical features like coastlines, rivers, mountains, and vegetation to guide them.
- Stars and the sun – Migrating birds use celestial cues to orient themselves and stay on course.
- Smell – Scents wafting from land, such as plant aromas, may draw birds towards their target wintering grounds.
- Geomagnetism – Hummingbirds and orioles sense the earth’s magnetic fields through special cells containing iron oxide. This acts as a natural GPS.
With such amazing senses and abilities, it’s no wonder these tiny travelers can pinpoint winter sites thousands of miles away with precision year after year!
When do they migrate north again?
Hummingbirds and orioles make the return trip north again in spring as conditions warm, insects hatch, flowers bloom, and nesting instincts kick in. Here’s when to expect them on their journey back to your feeders:
- Ruby-throated hummingbirds – Mid February to May, depending on latitude.
- Rufous hummingbirds – Mid March to early May, timing their return around flower blooms.
- Baltimore orioles – Mid April to late May as insects become abundant.
- Orchard orioles – Early May, coinciding with fruit trees blossoming.
Males typically arrive at northern breeding grounds first to scout out territories before females follow days to weeks later. Then the breeding season and nest building begins!
How long does migration take?
For these petite birds, migration is an incredible feat. One-way trips may stretch thousands of miles! Let’s look at estimated duration for key species:
- Ruby-throated hummingbird – 37 to 62 days on average for fall migration, making stops along the Gulf Coast.
- Rufous hummingbird – A week solid for a nonstop ocean crossing, a total trip up to 3 months with stops.
- Baltimore oriole – 10 days or more of continuous flying over land to Central America.
- Orchard oriole – Up to 18 days stopping minimally along the Gulf Coast.
These tiny travelers display incredible endurance. Their nonstop flights can stretch 500 miles or more at speeds around 20-40 mph!
What routes do they take?
Hummingbirds and orioles follow established migratory flyways or routes that provide the best food and shelter. However, they aren’t necessarily set paths. Migration routes may vary by factors like weather, food availability, and more.
Here are major flyways used:
- Ruby-throated hummingbird – Follows the Atlantic Flyway along the East Coast into Florida/Gulf Coast
- Rufous hummingbird – Many take the Pacific Flyway down the West Coast
- Baltimore oriole – Funnels down the Atlantic Flyway into Central America
- Orchard oriole – Heads south via the Central or Mississippi Flyways
Banding programs that track hummingbirds and orioles with tagged leg bands have revealed more about their migration routes and timing over the years.
How do they navigate their migration routes?
Hummingbirds and orioles navigate their seasonal passages using these natural aids:
- Instinct – Following inherited mental and genetic cues.
- Landforms – Using mountains, coasts, rivers and vegetation patterns.
- Celestial navigation – Sensing the sun’s position and patterns of stars.
- Smell – Detecting scents of features like flowering plants and forests.
- Earth’s magnetic field – Using their internal magnetoreception ability.
Younger birds follow experienced adults to learn routes their first year. Amazingly, if weather blows them off course, they can get their bearings and recalibrate back to their target path.
What dangers do migrating hummingbirds and orioles face?
Migration is a risky endeavor for such tiny birds. Here are some key hazards hummingbirds and orioles encounter along their migratory path:
- Exhaustion – Burning too much fat reserves before reaching rest stops.
- Extreme weather – Storms, high winds blowing them off course.
- Limited food/water – Finding enough nourishment to continue.
- Predators – Hawks, cats, snakes.
- Collisions – Hitting buildings, cell towers, vehicles, or aircraft.
- Habitat loss – Crucial rests stops converted to unsuitable habitat.
Up to 50% of birds don’t survive migration due to these hazards. However, those that make it reap the benefits of winter feeding grounds rich in fruit and insects their survival depends on.
How do they physically prepare for migration?
Hummingbirds and orioles undergo some incredible physiological changes leading up to their marathon migrations. Let’s explore their preparations:
| Changes | Details |
|---|---|
| Hyperphagia | Birds nearly double their weight by stocking up on 25-100% more food daily in the weeks before migrating. They build critical fat reserves for energy. |
| Fat deposition | Special fat stores enlarge along their chest and abdomen to fuel flights. |
| Flight muscles | Pectoral muscles that control wing beating grow substantially by up to 27% larger. |
| Digestive system | Parts like the intestine and liver grow as well to quickly process more food. |
| Water balance | Birds appear plump as their body increases water retention by up to 40% more. |
These sometimes extreme changes ensure hummingbirds and orioles are equipped to fly astonishing distances!
What do they eat along migration routes?
Fueling up is key for successful migration. Here are top foods hummingbirds and orioles eat along their migration routes:
- Hummingbirds – Flower nectar, sap, tree honeydew, small insects like gnats
- Orioles – Berries, fruits, oranges, mealworms, nectar
Backyard bird watchers can help provide needed energy by keeping feeders stocked and gardens full of blooms or fruiting plants.
Do they migrate alone or in flocks?
How hummingbirds and orioles group up varies by species:
- Ruby-throated hummingbirds – Generally solitary migrants.
- Rufous hummingbirds – Often migrate in loose flocks for safety.
- Baltimore orioles – Tend to migrate in small flocks or family groups.
- Orchard orioles – Usually migrate solo or in pairs.
While often solo travelers, hummingbirds and orioles congregating in numbers at stopover sites isn’t uncommon. Safety in numbers helps during such a risky journey.
Do they migrate during the day or night?
Most hummingbirds and orioles migrate by day when they can see and use visual landmarks and the sun’s orientation. However, factors like weather influence this:
- Hummingbirds may fly low and short hops by day, then ascend to high altitudes for long haul overnight flights.
- Orioles tend to migrate only during the day.
- Bad weather like strong headwinds may force migrating at night instead.
- To cross the Gulf of Mexico nonstop, birds must fly overnight above 500 feet where winds are more favorable.
These astonishing travelers are incredibly adaptive to keep on track even flying 18+ hours overnight by starlight alone.
Conclusion
While their absence leaves a void in summer gardens and forests, witnessing the massive migratory journeys hummingbirds and orioles undertake is truly breathtaking. Their navigational skills and physical resilience during months of travel allows their survival and return the following spring. Supporting these tiny travelers by providing food sources along their route helps them complete the migration cycle year after year.
