The chestnut-sided warbler is one of several bird species you might find in a foraging flock in Maine in late summer. Credit: Courtesy of Doug Hitchcox

I am frequently asked where I get the inspiration to write so many different birding columns. Often, the ideas just come to me. Literally.

Here I am, suddenly surrounded by inspiration. I am sitting in an Adirondack chair on my deck, reading quietly. Suddenly, it’s not so quiet.

The trees have jumped to life with birds. Among them, the chipping sparrows are particularly abundant. A whole family is working my yard, some in the trees, some on the ground. The two adults are obvious, with their small size, clear white breasts and rusty caps. The five youngsters are anything but obvious. Unlike their parents, they are mottled, streaky and capless. Chipping sparrows are named after the chip notes used for communicating with each other. They’re currently chipping a lot.

A black-and-white warbler has just landed on the rail, 6 feet away. She’s looking at me, wondering whether I’m a threat, as she picks small insects out of the cobwebs that habitually decorate my porch. Another black-and-white warbler is gleaning insects from the adjacent hemlock.

A black-throated green warbler has descended from the nearest oak onto a lower limb. They nest near my yard, but I haven’t actually seen one for a month, ever since they stopped singing. An adult and an immature red-eyed vireo are in the same tree, two limbs higher.

Farther back in the foliage, I’ve got glimpses of three more warblers: an American redstart, a northern parula and an immature chestnut-sided warbler. The latter is in its “confusing-fall-warbler” plumage, which perplexes and annoys everyone. It doesn’t look like a chestnut-sided warbler at all!

A flurry of nuthatches, both white-breasted and red-breasted, are chattering loudly and devouring the sunflower seeds at my feeder. American goldfinches are hitting the thistle feeder. A brown creeper is climbing a balsam behind them. Hairy and downy woodpeckers are probing bark, flitting from tree to tree, navigating around each other. In comes an impossibly young yellow-bellied sapsucker, in its drab, streaky plumage.

Most of these birds nest in my neighborhood. Some of them don’t, such as the ruby-crowned kinglet I am now watching. Two yellow-rumped warblers are calling from above it. They have a call note that is distinctly different from other warblers. When I hear the “quips,” I know they’re there. A hard-to-identify flycatcher just flew off a branch to snatch a moth. It’s not one of my resident eastern phoebes. I think it’s an alder flycatcher, which also doesn’t nest close by.

I am witnessing a foraging flock. Foraging flocks happen when mixed species come together to feed in a concentrated grouping. It’s a little chaotic and haphazard, especially when it contains dissimilar birds with dissimilar feeding habits. They scour the tiny area, moving slowly through the forest. One study suggested that the flock moves at about one-fifth of a mile per hour. I pity the grad student who had to time that movement. Worst. Thesis. Ever.

The primary benefit for the birds seems to be safety. Not only are more eyes likely to spot incoming predators, but foraging flocks seem to be built around key species that are particularly good at spotting trouble. Chickadees, nuthatches and titmice are ever-vigilant. They’re also ever-vocal. Their warning calls are universally understood by other birds.

It’s also likely that a sufficiently large flock of birds is apt to spook prey. Insects startle and dart away from the flock, getting gobbled in the process. Despite the high number of predators in a concentrated area, competition is quite low. The food preferences and feeding styles of each species differ enough that they’re not bumping into each other or stealing meals. As I watch this flock move through, some are gleaning from leaves, some are probing bark, some are aerial fly-catching.

Foraging flocks can happen at any time of year, but they are most prevalent in late summer. At this point, birds are preparing for migration or winter. Most young are capable of feeding themselves, leaving parents free to take care of their own needs.

This is the nature of songbird-watching in August. Things are quiet for a long time. Then suddenly, bam! — dozens of birds in one spot. The first step in enjoying this phenomenon is simply to notice when it’s happening, when something weird is going on. Pay attention to the chickadees when they get noisy.

My inspirational foraging flock has moved on. It’s quiet again. I can resume my reading, as soon as I put a period on the end of this … sentence.

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.