I see them whenever I lead bird walks—birders who cannot find the objects of their affection with their binoculars. When they do manage to find a bird they can’t keep it in their binocular field, can’t see field marks, and can’t distinguish subtle colors. Often they leave in frustration before the walk is over. These poor souls don’t realize that their problems are caused by the binoculars they’re using— maybe a pair that once belonged to their grandfather, or cheap compacts, or a pair with some ridiculous configuration, like the 16x32s I saw on a recent walk (more on the numbers later), which were designed to appeal to unknowledgeable buyers. There’s no getting around the fact that birders—even beginners—need more from their binoculars than any other users. “Bird-worthy” binoculars must be bright enough to show subtle features in poor light and sharp enough to resolve fine detail. They must focus quickly enough to “get on” a fast-moving bird. They must...