It’s inevitable. Whenever I’m standing along a remote roadside, peering at a bird, every passing tourist slows down, thinking I’m looking at a moose. I’m going to design a T-shirt that says: “No, it’s not a moose.”

I dread the next question: “What are you doing?” I can explain that I am “birding,” but then I have to explain what “birding” means. If I say I am “birdwatching,” no further explanation is necessary.

There is a difference between birding and birdwatching, but the difference is unexplainable. Naturally, I’m going to try anyway.

There is no semantic difference between the two terms, and they are often used interchangeably. However, everyone engaged in actively pursuing birds perceives a difference. You know who you are. It’s roughly equivalent to the difference between golfing and golf-watching. Birdwatching is a pastime. Birding is a sport, sort of.

In my mind, it’s the difference between passive and active. When finches come to my feeder and I observe them out the window, I’m a casual birdwatcher. When I grab the binoculars and locate a secretive warbler sitting in the treetop above the feeder, I’m a birder. When I go for a walk and appreciate the birds I see, I’m a birdwatcher. When I veer off the path and chase them into the woods, I’m a birder.

Over time, even the most casual birdwatcher gets better at identifying birds. But birders are continuously working to improve their skills. They go on walks, field trips and tours. They learn from experts. They read. They practice.

A review of antiquated dictionaries reveals that the term “birdwatcher” is older than “birder” by a couple of decades. Before 1918, birding was like fishing — the intent was to bring the quarry home for dinner. “Bird” has been a noun for a long time. It has been a verb for less than a century.

There is no bright line between birdwatching and birding. It’s a continuum. But, in an effort to settle the matter, I’ll borrow an incontestable standard of evidence from Deflategate’s Roger Goodell. If you meet any of the following tests, you are “more likely than not” to be guilty of birding.

If you notice birds while traveling, you’re a birdwatcher. If you travel to see birds, you’re a birder.

If you drive to see a rare bird in Maine, you’re a birder. If you go because your friend drags you along to see it, you’re a birdwatcher.

If you can recognize a hawk, you’re a birdwatcher. If you can recognize the difference between a sharp-shinned hawk and a Cooper’s hawk, you’re a birder. Actually, if you even know there is a difference, you’re a birder.

If you can identify a gull, you’re a birdwatcher. If you can tell how old it is, you’re a birder. (In my case, I know how old it is; I just don’t care that much.)

If you can identify a warbler by sight, you’re a birdwatcher. If you can recognize it by sound, you’re a birder. If you can recognize it by behavior or habitat, you’re definitely a birder.

If you have binoculars, you are a birdwatcher. If you have binoculars that cost more than your monthly mortgage, you’re a birder. If you are concerned about binocular qualities such as close focus, eye relief, field of view and image brightness, you’re a birder. Heck, even if you know what those things mean, you’re probably a birder.

If you have a spotting scope, you’re a birder. Who else would spend a thousand dollars to identify a duck?

If you have an identification guidebook on your bookshelf, you’re a birdwatcher. If you have every guidebook on your bookshelf, you’re a birder. If most of those guides are obsolete, but you would never consider parting with one, you’re definitely a birder. Seek help.

All birders and most birdwatchers know what a life list is — a list of birds that have been seen in one’s lifetime. Even the most casual birdwatcher may keep a life list. But if you have a life list … and a yard list, a county list, a state list, a year list … you’re a birder. If you know that an “official” list conforms to guidelines set forth by the American Birding Association and that a bird is only “countable” if it wanders into the listing area on its own, you’re definitely a birder.

If you read this column, you’re a birdwatcher. If you disagree with anything in today’s column, you’re undeniably a birder.

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.