On a cool May morning, dozens of birds chatter in the trees, darting playfully back and forth in the Costa Rican rainforest. Among these, we hear the shorter, quieter chirps of hummingbirds at La Selva biological station in Braulio Carillo National Park. Although they can fit in the palm of your hand, their bright colors and long, sharp bills make them easy to spot.
Many plants and flowers depend on hummingbirds for pollination — including heliconias, firebushes, and bromeliads.
These brightly colored, long, tubular flowers are most efficiently pollinated by hummingbirds, whose bills fit into the flowers’ long, thin openings. As they retrieve the nectar, the hummingbirds pick up pollen, and transfer it from flower to flower.
These plants support Costa Rica's biodiverse ecosystem by driving complex food webs; providing homes for insects; and supporting specialized local pollinators, like hummingbirds.
Emanuel Brenes, a tropical biologist and conservation expert, studies plant and hummingbird interactions. He discussed the implications of hummingbirds’ pollination efforts.
“Entonces, como estas flores evolucionaron para atraer colibríes, generalmente son visitadas solo por colibríes,” Brenes said. “Entonces hay una relación de especialización entre esas flores específicamente y los colibríes porque no están siendo visitadas por insectos.” (These flowers have evolved to attract hummingbirds. There’s a specialized relationship between the two and they’re not being visited by other insects.)
Hummingbirds become an effective catalyst for sustaining these native plants, he said.
“If we lose the specialist plants in the middle and the low elevations, we will have problems with the pollinators — in this case, hummingbirds,” Brenes said.
Brenes studies these plants in the lowland regions that are rich in vegetation and moisture. But he said these areas are vulnerable to habitat loss. His work is part of his ongoing and yet to be published research project.
The effects of hummingbird habitat loss
At the bustling La Selva visitor’s center, naturalist Jeremi Telecaluna pointed out birds after his tour. Telecaluna said if there are declines in hummingbirds, it could have a negative impact on the rainforest.
“Well, probably we would also [see] declines in trees or forests, because one of the main pollinators are hummingbirds,” Telecaluna said.
But hummingbirds aren’t only at risk in the tropics. Back in Nevada, urbanization is overtaking the low grasslands and open fields in the northern part of the state. And as a result, it’s consuming the natural hummingbird habitat.
Ornithologist Alan Gubanich said urban expansion impacts our local hummingbird populations.
“Well, habitat removal and destruction, I think, has been the major cause of the loss of so many billions of birds,” Gubanich said. “So without the habitat, there's no food for them and no place for them to breed.”
Supporting the hummingbird populations
One way humans can help maintain hummingbird populations is by placing feeders. Telecaluna said this can have positive effects.
“I'd prefer to get them on the feeder,” Telacaluna said. “Why? Because what happens if [I] cut [into] their habitat? They are going to disappear. So I'd prefer to keep [them] on the feeder and not destroy their habitat, for example."
Gubanich agreed. He said although natural gardens are better, feeders will keep the hummingbirds alive. And their populations can also be supported by planting native plants including columbine and aster.
Large scale research and conservation efforts, like Brenes’ ongoing studies and the Northwest Nevada Bird Alliance can increase awareness of these birds and their threats. Hummingbirds can also be supported on the local level by simply putting out a backyard feeder and planting as many hummingbird-friendly native plants as possible.
This story is in partnership with the Hitchcock Project for Visualizing Science and the Reynolds School of Journalism.