An American tree sparrow is perched on my thistle feeder. He hates it there.

With several inches of snow already on the ground and more falling early this week, some of the neighborhood birds have finally decided to dine outside my window. Normally, the tree sparrows would be feeding on the ground. But there’s been so little activity lately that there is scant food spilled beneath the feeders.

So there he sits, glumly grabbing a few Nyjer seeds, surrounded by happy goldfinches. It’s a contrast in feeding styles.

Watching birds at a feeder is charming, but observing their behaviors is fascinating. Some species fly in, grab a seed, and fly off. Others sit on the feeder, chomping away. Still others prefer to feed on the ground or limit themselves to platform and tray feeders. Some stick to the sunflower seeds. Some sample the Nyjer and suet. Some species visit routinely, while others arrive only when the weather is bad. There are four tree sparrows beneath my feeder. They’ve likely been around my yard for weeks, unnoticed, until snowfall drove them to me. Surely there must be a reason for these varied strategies.

As usual, it comes down to one thing: Birds want to eat food, not be food. Visiting feeders is risky business. Predators are sometimes attracted to the commotion. The benefits of snatching a bite in the backyard far outweigh the risks, but the birds are naturally cautious. Lingering on a feeder invites trouble.

Except if you’re a finch. Finches, grosbeaks and cardinals have heavy, seed-crushing bills. They can eat and watch for danger at the same time. Finches also tend to feed in flocks during the winter, giving them the advantage of many eyes looking for danger.

Chickadees, titmice and nuthatches have narrower bills and must hammer their seeds open. That means they must look at the seed as they hit it, diverting their attention from possible peril. Often, they need to wedge the seed into a bark crevice in order to hold it steady while they hammer. Thus, it’s common to see these birds grab one seed quickly, and fly off to a place where they can crack it safely.

Likewise, blue jays have long pointed bills and they, too, must open the shell before they can eat the seed. However, they can wedge it between their toes while remaining at the feeder. You’ll notice they tend to look around for trouble before beginning to hammer a seed, and they don’t usually linger at a feeder the way finches do.

Sparrows and juncos have bills heavy enough to crack seeds, but these birds are typically ground feeders, and they are accustomed to eating there. They will land on pole-mounted platform feeders, but they’re uncomfortable on hanging feeders.

This is where it gets really interesting. Now that you’re noticing which birds linger at the feeder and which birds are grab-and-go, pay particular attention to the birds carrying away a seed. They may be stashing it for later. Many birds cache food. Chickadees and nuthatches often hide away a morsel for short-term storage, or even long-term. Some birds, such as blue jays, hide food year-round.

Of course, for this strategy to work, you first have to remember where you put the food. Evolution favors those birds with good memories, so it’s no surprise that they’ve gotten really good at remembering. In some cases, birds improve their brainpower as needed. The brain size of a chickadee actually increases in winter, providing more memory.

Moreover, this strategy only works for birds that have a home range. Finches wander. Chickadees mostly stay put. They know your yard better than you do.

The other key component of a caching strategy is to keep your cache a secret. Birds go to great lengths to hide their stash. Most spread the food around, so that only a small amount may be pilfered. A few, like crows, jays and some woodpeckers, maintain bigger treasure troves. They take great pains to avoid being seen, sometimes pretending to cache food in a false location before slinking off to their actual hoard. They will even re-hide food, if they suspect they’ve been noticed.

Nuthatches are notorious for stealing from each other’s caches, even from their mates. If you spy two nuthatches grabbing seeds at the feeder, watch to see if they head off in different directions, each trying to avoid the prying eyes of the other. It’s a jungle out there.

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.