One of the problems with birding is that it is an art, not a science.

Sometimes, a bird with very distinct markings stands still right in front of your binoculars. You can go home and check it off on your list with absolute certainty. That is what I did when I saw the great horned owl the other day outside the Raptor Trust. It sat in a tree, unmoving, for over 30 minutes. It was large, had readily observable “horns,” and looked exactly like the injured great horned owl resting in a cage nearby.

Check!

Usually, though, it is not so easy. Many bird species look similar, so you kind of have to guess which one you’ve seen. Other times, you don’t get a great look at the bird before it flitters off. Remember that great Nelly Furtado song that goes, “I’m like a bird, I wanna fly away. . .”

She wasn’t kidding.

When there is doubt as to what bird you have seen, you must use logical deduction to determine which one it probably was.

Last week, I saw a pigeon-sized bird of prey sitting on a telephone pole in my parking lot. I was on the way to the mall, not the bird sanctuary, so I didn’t have my binoculars on. The bird, which had a facial marking like a sideburn and blue-grey spots on its chest, sat there for a minute or less, before flying away. When I got back from my shopping trip, I took out my National Geographic field guide, and tried to determine what bird I had just seen.

My mother had seen this bird hanging around with feathers in its mouth, so I determined it was probably a bird eating raptor. Because I live in a city, I first assumed it was a peregrine falcon. But peregrine falcons are much bigger than pigeons--in fact, they eat them--so unless it was a very tiny peregrine, I had to rule that out. A kestrel would be about the right size, and a merlin would be exactly the right size. According to the field guide, kestrels like to sit on wires, but are birds of open country. The parking lot was hardly open country, but it was very close to a wetland bird sanctuary. Merlins, according to the guide, are uncommon. They also have no sideburn like markings on their faces.

In the end, I decided on the kestrel. I didn’t notice any rusty feathers on the bird, but I didn’t get the clearest or longest look at it. I know there are kestrels in two wetland parks in nearby towns, and the ecosystems there are similar to the ecosystem in the park behind my apartment. I saw a kestrel once before (and only once), so I didn’t add a new member to my life list. Was it really a merlin? Or a small peregrine? I’ll never know.

Birding is an art, not a science. In some or even most cases, you have to rely on your memory, field guides and common sense to figure out which bird you’ve most likely seen. It’s almost like jury duty. You’re never really sure if the person did or didn’t do the crime. You just have to figure out beyond a reasonable doubt what happened. That’s what makes this hobby so compelling and sometimes, so frustrating.