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A Long-distance Speedster

A Tiny Rufous Hummingbird Hovers as It Searches for Flowers in the Santa Cruz Mountains. Santa Cruz, California.The tiny, stunning, and delightfully hot-tempered bird featured in our Photo of the Week earns smiles from all who see it staunchly defending a feeder perch or group of flowers it’s decided to call its own. Making up for its diminutive stature by an outsized ferocity, it will not only chase away any or all who enter its domain but will even go so far as to fly at and chest bump a larger hummingbird that doesn’t quickly vamoose.

And does this little bird travel. From historical wintering grounds in Mexico, it migrates as much as 4,000 miles every year to breeding territories as far north as South-central Alaska. Traveling north, it seems to prefer the Pacific coast. (That’s how we get to see the Rufous in the early Spring.) Once its breeding season ends, the Rufous apparently prefers to travel south via the Rocky Mountains.

But this intrepid little traveler no longer restricts itself to its historical Western territory. Steadily warming seasonal temperatures have encouraged the Rufous Hummingbird to expand its wintering territory into the Southeast—from far-southern Texas to South Carolina—and more Rufous have been ranging into the Northeast during breeding season, areas where only immature Rufous previously ventured.

But according to the Audubon Society, even though the Rufous Hummingbird has been expanding its territory, its population has been steadily declining over the past several decades—likely due to Climate Change, habitat loss, and the length of its migration north.

The issue? Food.

The Rufous, one of the smallest—up to 3.1 inches in length—and lightest—just 0.176 ounces—has, like all hummingbirds, an extremely high metabolism rate, beating its wings up to 90 beats per second. To support its energy expenditure, the Rufous needs to consume approximately 160,000 calories a day. Achieving this means eating five times their body weight daily, a feat they accomplish by feeding every 10-15 minutes and sipping nectar from as many as 2,000 flowers a day.

Consuming so many calories while also migrating thousands of miles to and from its breeding territories requires exquisite timing—a Rufous needs to find flowers as they begin to bloom (i.e., at peak nectar-production time) at each and every step of its journey north. Arrive at an area too early or too late, and it will find few or no flowers at their peak of nectar production.

While Rufous hummingbirds have thrived for hundreds of thousands of years in North America artfully performing this choreographed migration to and from its breeding grounds, the severity and rate at which climate change has unfolded may prove very troublesome to the Rufous and other hummingbird species. Increasing temperatures—with one exception, “the 10 warmest years in the 134-year record all have occurred since 2000,” with 2015 ranking “as the warmest on record”—have caused flowers to bloom much earlier than usual. Researchers studying the Pacific Northwest flower bloom, for example, have found that Glacier Lilies, a species particularly important to Broad-tailed Hummingbirds, have been

blooming some 17 days earlier than they did in the 1970s. This means that their blooming is no longer in synch with the arrival of the hummingbirds that rely on the nectar. By the time the hummingbirds arrive, many of the flowers have withered away along with their nectar-filled blooms.

The Rufous Hummingbird, a species noted for starting its northerly migration as early as February, travels through multiple climatic regions—ranging from the deserts of the Southwest to Alpine areas in the Sierras and Cascades—and needs to find flowering plants as it passes through each of those regions. As the climate continues to warm, will the migratory progress of the Rufous coincide with the erratically changing blooming patterns of the many flowering plants along its path? Will the plants themselves continue to flourish in successive seasons if the hummingbirds they depend on arrive too early or too late to pollinate them?

The Audubon Society, which has studied the effects of Climate Change on all North American bird species, does not offer encouraging news. It lists the Rufous Hummingbird as one of its “climate endangered” species, forecasting that “by 2080, this glittering hummingbird is projected to lose 100 percent of [its] non-breeding range in the United States”—i.e., its southerly range—and “that the hummer’s summer range will also be disrupted and move north.”

As mentioned above, the East seems to be offering some hope for the Rufous. Warming temperatures and the abundance of backyard hummingbird feeders have apparently allowed the Rufous and other hummingbirds to become year-round residents where they once were only occasional visitors. And perhaps we will finally realize how dire the consequences of our dependence on fossil fuel are for the species on this planet, including our own. Time will tell.

You’ll find more information about Hummingbirds and Climate Change in the following articles:

Rufous Hummingbirds
Cornell Lab of Ornithology

Hummingbirds and Climate Change
Andes Mountain Hummingbirds Might Lose Habitat, Risk Extinction, as Climate Warms
Annual Changes In Hummingbird Migration Revealed By Birders’ Sightings
Assessing Migration of Ruby-Throated Hummingbirds (Archilochus colubris) at Broad Spatial and Temporal Scales
Bird Migration Patterns Changing Due to Climate Change
Climate Change Causing Hummingbird Missed Connections
Climate Endangered: Allen’s Hummingbird
Climate Threatened: Black-chinned Hummingbird
Climate Endangered: Rufous Hummingbird
Global Warming and California Birds
How Hummingbirds Journey North
Hummingbirds and Climate Change
Hummingbirds at Home: The Effects of Climate Change on Feeding Behavior
Hummingbird Monitoring in Colorado Plateau Parks
Hummingbirds, Facing Drought and Food Shortage, Get Some Human Help
Hummingbirds Migrating Earlier in the Spring
Inspiring Action on Climate Change and Protecting America’s Birds
Projected changes in elevational distribution and flight performance of montane Neotropical hummingbirds in response to climate change
The Smallest of Pacific Birds

Global Warming
Global Analysis – February 2016 (State of the Climate)
Global Temperature
The planet had its biggest temperature spike in modern history in February
Planet’s Heat Record Shattered—and 2016 Likely to Be Even Warmer