by Alison Mitchell, Executive Director, New Jersey Conservation Foundation
For a brief but magical window in late April and early May, New Jersey becomes a crucial stopover for one of nature’s tiniest travelers: the ruby-throated hummingbird. As the only species of hummingbird that breeds in eastern North America, these dazzling little birds make an incredible journey north each spring from southern Florida, southern Mexico, and mostly Central America. A few stay in New Jersey to breed, but most pass through to points farther north.
Don’t blink, or you might miss them! In addition to their mostly brief appearance here, ruby-throated hummingbirds are tiny. They weigh less than a teaspoon of sugar and are roughly the size of a crayon. But in preparation for migration, they bulk up with energy-rich fat and more than double their body weight! Despite their tiny stature, these fascinating creatures are vibrant and full of personality. Males and females are easy to tell apart (a trait called sexual dimorphism shared by many birds): the males shimmer with metallic green feathers and a brilliant ruby-red throat, while the females sport soft white bellies with faint gray streaks.
David La Puma has been banding hummingbirds in New Jersey for over a decade. “All of my equipment is so tiny,” he remarks, noting that his banding tools are kept in an old Altoids mint tin. La Puma is part of a hummingbird banding network that spans the world. He works with other banders to track ruby-throated hummingbirds, and to learn more about vagrant species who have flown off course. “There is so much we still don’t know,” he says.
By late summer, usually around August, most of these little birds begin their southward migration. By the first week of September, the majority of ruby-throated hummingbirds have already left this state we’re in, headed for warmer climates. Adult males tend to be the first to go as they search for prime winter refuges – just as they are the first to leave for summer breeding grounds. It’s all about securing resources early, both for breeding and for survival.
Their southbound voyages are as fascinating and mysterious as their northward journeys in spring. While many of the southbound birds fly straight across the Gulf of Mexico, some take a detour and fly around the Gulf instead. La Puma shared a surprising story about a bird tagged in Alabama, which didn’t head south as expected but instead circled around Florida before ending up nesting near Gainesville. “What do we know, really?” he asks. These birds clearly have a remarkable ability to navigate but they are still a bit of a mystery to scientists.
One of the most striking things we’re learning about hummingbirds is their ability to remember specific places. The tiny travelers are known for their “site fidelity” – the tendency to return to the same locations year after year. It’s as if they have a mental map of their favorite spots. “I’ve banded birds at the same sites for years, and they keep coming back,” says La Puma. “They know these places provide a reliable food source and shelter.”
The migration of ruby-throated hummingbirds is a true marvel. By keeping a clean feeder up during their migration periods, avoiding pesticides (especially neonicotinamides), and planting native nectar-rich flowers, you can help fuel this epic journey.
To learn more about how to attract hummingbirds to your yard, visit https://njaes.rutgers.edu/fs1316/.
To learn more about how you can help preserve New Jersey’s natural resources, visit the New Jersey Conservation Foundation at www.njconservation.org or reach out to us at [email protected].
