Books, including ones written by knowledgeable ornithologists, have stated for many years that the flight pattern of Rufous Hummingbirds forms an oval. Some feature drawings of a Rufous Hummingbird display like the picture to the right. And Journey North science writer Laura Erickson saw what looked like an oval flight display by what looked like a Rufous Hummingbird when she was birding in Ramsey Canyon in Arizona in April, 1982.
But Mike Patterson, who has been carefully watching Rufous Hummingbirds for 20 years in the Oregon and Washington areas, has never seen this oval display. Dr. William Calder is the ornithologist who wrote the Rufous Hummingbird entry in the basic reference used by researchers, the Birds of North America. Dr. Calder has researched the Rufous Hummingbird in the Rocky Mountains for over 20 years. Here's how he describes what he's seen: "After climbing away from female perched low in vegetation, near ground, a male reversed heading as he entered dive, levelling out after passing over female, then emitted a series of 4-5 rip-saw-like dit-dit-dit-deeer with Doppler-like decrease in pitch, followed by 3-4 less audible, dull "plops," presumably made by tail feathers." And David Allen Sibley, author of The Sibley Guide to Birds, shows the display in the same way that Mike Patterson has witnessed it:
Hypotheses About the Oval
Laura Erickson thinks it's possible Rufous Hummingbirds make pairs of rise-and-dive movements in different planes, so from some angles it LOOKS like a complete oval.
Patterson has two hypotheses:
Is it possible that written descriptions of a rise and then a J-dive could have been misinterpreted, and misdrawn as a complete oval? Let's see!
Try This! Drawing from Someone Else's Description
You need two partners and an animal--a classroom pet such as a guinea pig or gerbil, or a squirrel or pigeon outdoors. One partner will be the observer. This person will watch the movements of the animal for five minutes and write down a description of every move. Then the other partner, the transcriber, will use those notes to draw a pattern of the animal's movements. Does the drawing come close to what the observer actually saw?
Back to the Original Question...
Do Rufous Hummingbirds really fly in an oval? Scientists learn the answers to questions like this in two different ways: they make careful observations and experiments on their own, and they read about the careful observations and experiments that others have made. Sometimes errors enter--sometimes an ornithologist makes a mistake in the original observation, sometimes an ornithologist witnesses a unique event and jumps to the conclusion that it's common, and sometimes an ornithologist describes something in an unclear way. Little by little, by publishing their findings, and reading and discussing their work together at professional meetings and more informally, ornithologists learn from one another and build up the body of knowledge we have of birds.
YOU Can Help the Research
That's the excitement of science: working together, people are still finding the answers to many questions, and every time we get one answer, we think of more questions!