Hummingbirds are amazing little birds that can hover in midair and fly backwards. They have captured the fascination of people for centuries. Hummingbirds are native to the Americas and there are over 300 different species. However, only one species regularly breeds in New Jersey – the Ruby-throated Hummingbird. Like many other bird species that breed in the northern United States and Canada, the Ruby-throated Hummingbird migrates south for the winter. Their tiny size belies an incredible migratory journey. So where exactly do New Jersey’s hummingbirds go when they migrate? Let’s take a look at the details.
Ruby-throated Hummingbird Facts
The Ruby-throated Hummingbird (Archilochus colubris) is the most common and widely distributed hummingbird species in eastern North America. Here are some key facts about these tiny birds:
- They are the smallest breeding bird in New Jersey, with males weighing only 2-4 grams and females 3-5 grams.
- Their name comes from the brilliant ruby-red throat patch on the males (females lack this patch).
- Ruby-throats have an extremely fast heartbeat and wingbeat. Their heart rate can reach over 1200 beats per minute and they beat their wings up to 80 times per second.
- They are the only regular breeding hummingbird species in eastern North America.
- Their main food source is nectar from flowers, but they also eat many small insects.
- Males arrive in New Jersey to establish breeding territories in late April or early May before females arrive.
- Females build a tiny cup-shaped nest out of plant down, spider silk, and lichens glued together with saliva.
- A female Ruby-throat may raise 2-3 broods per summer, with 2 eggs per brood.
- The young fledge from the nest in 16-22 days and reach sexual maturity in their first year.
- Ruby-throats breeding in New Jersey and across the Eastern U.S. and Canada migrate south to Central America and the Caribbean for the winter.
The Ruby-throated Hummingbird’s small size makes its migration all the more incredible. They must fly 500 miles or more non-stop across the Gulf of Mexico each fall and spring. Their metabolism enables them to go into a brief period of torpor to conserve energy on these long flights. Next, let’s look at details on their migration path and wintering grounds.
Migration Route and Timing
Ruby-throated Hummingbirds depart their breeding grounds starting in August. The southward migration from New Jersey peaks in mid-September but some individuals continue migrating through October.
Banding studies have revealed their migration route:
- They generally migrate across the eastern United States, flying southward along the Atlantic Coast.
- At some point, usually in Texas or Louisiana, they turn east and fly 500+ miles nonstop across the Gulf of Mexico to the Yucatan Peninsula.
- From there, they follow the Caribbean coast of Central America south to their wintering grounds.
- In spring, they retrace this route back to the breeding grounds, arriving again in New Jersey in April and May.
This is an arduous journey for a bird that weighs less than a few pennies! Cold fronts with northerly winds in late summer and fall provide the cue for them to start migrating. Conversely, south winds help push them northward again in spring.
The northward migration happens over a broader time period from late February through May. The peak passage through New Jersey occurs in the second half of April into early May.
Winter Range in Mexico, Central America and the Caribbean
Once Ruby-throats reach Central America and the Caribbean, they spread out across a large winter range:
- Southern Mexico
- Belize
- Guatemala
- El Salvador
- Honduras
- Nicaragua
- Costa Rica
- Panama
- Cuba
- Bahamas
- Turks and Caicos
- Dominican Republic
- Jamaica
- Puerto Rico
In their winter habitat, Ruby-throats prefer tropical forests, forest edges, gardens, and plantations where nectar-producing flowers are abundant.
Some key nectar plants used in winter include:
- Firecracker plant
- Red ginger
- Bougainvillea
- Hibiscus
- Coral bean
- Turk’s cap
- Palm flowers
Interestingly, a portion of the western breeding population of Ruby-throats winters primarily in coastal western Mexico. But eastern breeding birds like those from New Jersey occupy the winter range described above.
What Triggers Migration?
It’s amazing that a bird so tiny can travel thousands of miles between breeding and wintering grounds. What cues tell them it’s time to migrate?
- Seasonal Changes in Day Length: As days shorten in late summer, hummingbirds get an internal signal that it’s time to migrate south. Likewise, lengthening days in spring signal it’s time to migrate north and begin breeding again.
- Food Availability: The start of southward migration corresponds with dwindling nectar supplies as many flowers begin fading. Arrival on the wintering grounds matches up with peak flowering there.
- Weather: Drops in temperature and the passage of cold fronts provide favorable winds for migration. Hummingbirds migrate on days with steady tailwinds that aid their long-distance travel.
- Orientation Mechanisms: Hummingbirds use a variety of built-in compasses to orient their direction during migration, including a sun compass, ability to see polarized light, and sensitivity to the Earth’s magnetic field.
These orientation mechanisms keep them from getting off course during a long non-stop flight. Timing their travel with favorable winds enables this arduous journey for a bird that can fit in the palm of your hand!
Threats During Migration
Hummingbird migration is an endurance event. What hazards do hummingbirds face during their seasonal journeys?
- Lack of food: Finding adequate energy sources is a constant challenge. Hummingbirds need frequent rest stops with nectar supplies. Gardens, feeders, and flowering meadows provide crucial refueling stations.
- Inclement weather: Storms, high winds, or cold temperatures can be deadly during migration. Hummingbirds need enough food reserves to wait out poor conditions.
- Predators: Hawks, falcons, shrikes, and other birds of prey hunt hummingbirds on migration. Cats, snakes, and other predators also pose risks during stops.
- Geographic barriers: Major barriers like the Gulf Coast must be crossed in a single flight. Even smaller geographic features like mountains and deserts pose challenges.
- Habitat loss: Human impacts leading to fewer natural nectar sources raise difficulties finding food en route.
Yet despite these obstacles, Ruby-throats and other hummingbirds complete these grueling seasonal journeys with incredible tenacity. Their specialized physiology helps power this epic migration.
Physiological Adaptations for Migration
Ruby-throated Hummingbirds have many physiological and behavioral adaptations that enable their long-distance migrations:
- High metabolism: Hummingbirds have among the highest metabolic rates of any animal. This provides energy for hovering and enables fat storage for migration.
- Fat reserves: Before migrating, hummingbirds nearly double their body weight by building up fat stores for energy. This fat allows flying 500 miles or more nonstop.
- Torpor: To conserve energy on long flights, hummingbirds can enter short periods of torpor or hibernation lasting a few hours.
- Directional sense: Their sun compass, ability to see polarized light, and magnetic sensitivity provide excellent directional guides during migration.
- Preferred flight altitudes: Hummingbirds typically migrate at altitudes between 300 feet and 1,000 feet to catch favorable tailwinds.
- Wind drift compensation: They compensate for wind drift during migration by altering their direction and speed relative to the airflow around them.
- Slope soaring: They take advantage of rising air currents up the slopes of mountains that give an extra boost.
These adaptations allow Ruby-throated Hummingbirds to achieve one of the most incredible migrations relative to body size of any bird species.
Key Stopover Sites in New Jersey
While migrating through New Jersey, hummingbirds rely on certain key stopover sites to rest and refuel. Important stopover habitats include:
- Backyard feeders and gardens
- State parks with meadows and forests
- Nature reserves with native wildflowers
- Back dunes and scrub along the Atlantic Coast
- Riparian corridors along streams and rivers
Some top sites include Cape May Point State Park, Forks of the Delaware State Park, and the sandy scrub and dune habitats of Island Beach State Park. Homeowners and parks that provide nectar feeders help sustain hummingbirds on migration.
How to Support Migrating Hummingbirds
There are several ways people can help support migrating Ruby-throated Hummingbirds in New Jersey:
- Put up nectar feeders in late summer and keep them filled through October. Use a 4-part sugar to 1-part water ratio.
- Plant a hummingbird garden with native flowers like bee balm, cardinal flowers, and trumpet vines.
- Avoid pesticides that reduce insect populations hummingbirds depend on.
- Support parks, reserves, and open spaces that provide migration habitat.
- Keep cats indoors to protect birds during migration.
- Participate in citizen science by reporting hummingbird sightings on sites like eBird.
With a few simple actions, we can make a big difference for these tiny travelers on one of nature’s most incredible migratory journeys. The rewards of seeing them up-close are well worth the effort!
Conclusion
In conclusion, Ruby-throated Hummingbirds breeding in New Jersey and the rest of the Eastern U.S. embark on a phenomenal migration each year all the way to Central America and Mexico for the winter. They follow routes across the Gulf of Mexico and Caribbean relying on favorable winds and stored energy reserves. While facing many threats, these tiny birds exhibit amazing endurance thanks to specialized adaptations. With support along their migration path, they continue their incredible annual cycle connecting landscapes across the Americas! By providing hummingbird gardens, nectar sources, and stopover habitats, we can aid these remarkable migrants on their extraordinary journeys.
