-- HUMMINGBIRD Q & A --
Ecology #1

Ruby-throated Hummingbirds are small prey, so you might expect they have relatively small natural predators. There are references in the literature to hummingbirds having been killed and/or eaten by Sharp-shinned Hawks (above left), Praying Mantids, Largemouth Bass, Green Frogs and Bull Frogs (above right), and big Orb-weaving Spiders. There's even a record of a large dragonfly--a Common Green Darner, Anax junius--attacking, killing, and apparently flying off with a ruby-throat (although some experts believe the dragonfly actually caught a Hummingbird Moth). In the tropics, hummingbirds face additional dangers, including bird-eating lizards.

Hummingbird eggs would make a tasty snack for a squirrel or chipmunk, and a tree-climbing Black Ratsnake might take an incubating or brooding female, her eggs, or chicks.

Interestingly, one enemy of hummingbirds appears to be plants. There are reports of hummingbirds being impaled on cactus spines and hummers occasionally become mired in sticky tree sap. One well-documented hazard is the seed pod of Common Burdock, Arctium minus. These pods, known as "cockleburs," are covered by tiny hooks that usually attach to the fur (or pantlegs) of potential seed disseminators. Hummingbirds are so small, however, that when they come to feed on a purple burdock flower, they sometimes get snared by cocklebur hooks. This was the case for a Ruby-throated Hummingbird female we found one summer at the National Youth Science Camp in Bartow, West Virginia USA (above left). Fortunately, the bird was still alive and we were able to cut the hooks away from its leg and release it unharmed after banding the other leg.

Although hard to quantify, it's likely that more Ruby-throated Hummingbirds--like many wild species--are killed indirectly by habitat destruction than most other individual factors. Loss of habitat on the wintering and breeding grounds undoubtedly has an effect, as does destruction of important stopover points along the migratory path; for example, slash and burn agriculture in Mexico and Central America (above left) is bound to have a negative impact. Many hummingbirds also fly into stationary objects (picture windows, buildings, radio towers, etc.), while others are hit by cars and trucks on our busy highways.

And despite what pet owners might claim or believe, there are many instances each year of house cats (above right) hanging around hummingbird feeders or garden flowers and killing the tiny visitors as they drop in for some sugar water or nectar. (As their name implies, "house cats" should be keep indoors where they cannot molest wildlife of any kind.)