All wildlife faces hazards to survival, including weather, humans, pesticides, and so on. For tiny hummingbirds, however, predators are a significant source of risk.
Cats, both domestic and feral, are probably the most common predators of non-nested hummingbirds. Reports to the Society come in regularly, for example, of people whose cats carry a hummingbird in their mouth–sometimes dead, sometimes not. Reports of tailless hummingbirds are less likely to indicate a hummingbird in molt than one that narrowly escaped being caught by a cat. In the case of one species, the Critically Endangered Juan Fernandez Firecrown (Chile), cats are actually an important reason for the bird’s being close to extinction.
To reduce the risks from cats, feeders should be hung high: at least five feet (1.2 m.) above ground, and preferably positioned so that a stalking cat will be quite visible. If you have a cat and love hummingbirds–or any other birds–keep the cat inside!
Other birds, such as hawks, have been documented catching hummingbirds. Considering the differences in size, one wonders just how much nourishment a tiny hummingbird (typically only 3-4 grams, or 0.1 ounce) can provide to a large bird, but it happens nonetheless. In contrast to this, many people have observed hummingbirds pursuing or confronting a hawk, most probably in defense of a nest. This fearless behavior against overwhelming odds is but one of the reasons that hummingbirds evoke our admiration.
In the nest, eggs and chicks represent an easy target for a variety of predators: other birds, such as blue jays and crows in the U.S., and snakes, particularly in the tropics.