Goodness knows, life can be tough in a world of predators, especially when you weigh somewhere between 2.5 and 4 grams. But, as with many things in nature, species survival can be attributed to a variety of interesting factors – and not all of them obvious to the casual observer.
For example, researchers conducting a study in the Southwestern United States recently found hummingbirds benefit from protection by hawks.
The study, published in the journal Science Advances, reported a majority of hummingbird nests found within southeastern Arizona’s Chiricahua Mountains were built in close proximity to hawk nests. The hummingbird nests were built inside a “cone of safety,” extending downward, deterring predator jays because they will want to avoid getting too close to hawk territory and become prey themselves.
“If you want your hummingbirds to do well, you have to make sure your hawks are doing well,” said Harold Greeney, who was a postdoctoral researcher at the University of Nevada, Reno, while conducting the study.
Greeney and colleagues first wrote about the hummingbird survival rates in 2009 in The Wilson Journal of Ornithology. At that time, they observed that black-chinned hummingbirds (Archilochus alexandri) clustered their nest around Cooper’s hawks (Accipiter cooperii) and goshawks (genus Accipiter). In their more recent observations, researchers noticed that when hawks were near, Mexican jays (Aphelocoma wollweberi) — a predator with an appetite for hummingbird eggs and chicks — seemed to stay away from the nests.
The most recent research determined around 80 percent of the hummingbird nests were clustered near the hawk nests. When built near hawks, the nests had a daily survival rate of 31 percent. Outside of hawk territory, the daily survival rate drops to a mere 6 percent.
So, you might say that hummingbirds have learned to utilize a much larger bird species as their home security system – and with great success!
OK, so more hummingbird hatch and survive when their nests are built near raptors. Now the question: How do they know? Ah, the mysteries of nature!