First recognize that bigger isn’t always better. Binoculars bear two numbers: 7×35, 8×30 or 10×50, for example. The first is magnification. You’re fine with 7- or 8-power. Sure, a power of 10 makes the tanager appear even larger, but it also magnifies your own trembling (and who doesn’t tremble in the presence of a tanager?). Higher magnification also reduces your field of view – the breadth of habitat you see out there. You spot a bird, lift your binoculars for a look … and find no bird in view. If this is all too familiar, your optics might be too powerful (or your aim needs practice). I bird with a pair of 8x42s.

That second number is the diameter of the objective lens (the bigger end) in millimeters. A larger lens gathers more light and therefore improves the view, but it also adds weight and bulk around your neck or in your pack. There is little reason to go larger than 42 (or smaller than 30).

Which brings me to compact binoculars. Avoid them. With an objective lens around 20mm, the view is dark and dingy. And compacts are nearly impossible to use while wearing gloves or mittens during winter birding. Their only reason for existing might be as your spare pair in the glove compartment. I backpack with mid-sized 8x30s.

Next, beware of unruly eye-cups. We used to nestle our eyes into rubber eye-cups. Birders wearing eyeglasses would fold the eye-cups down to position their eyes the proper distance from the lenses. Modern eye-cups twist out to various positions, an innovation that has ruined some fine binoculars. Poorly designed eye-cups can twist on their own out of position. It can ruin your chance to see something fleeting and good. So, when shopping, be sure the eye-cups snap and lock in place – all the way down, all the way out and at one or more points in between.

Test drive any binoculars in lousy light – not bright sunshine, where most binoculars will perform well. Avoid gimmicks such as zoom lenses, built-in cameras and models with a technology that stabilizes your hand trembling. Make sure your binoculars can focus on objects as near as six feet. That’s because at some highly evolved point in your birding career you will discover the pleasure of watching insects (butterflies, dragonflies and tiger beetles, for example). And you will curse your binoculars if you must back away from an insect in order to get it in focus.

Even if you’re standing by your old clunkers, learn the diopter correction. It allows you to adjust your binoculars for the natural variation in your own eyes. The correction is easy to perform but varies by model. If it’s not right, everything you view will be out of focus. Once you’ve made the correction, however, your binoculars may be out of focus for the person who shares them with you.

Dirt, pollen, fingerprints, egg salad, coffee and worse will inevitably find your optics. The critical advice here (besides investing in lens solution and cleaning paper or a lens cloth) is to buy a lens brush. Always brush away grit before you start rubbing your lenses to clean them. And always rub gently.

Finally, on price, after doing careful research, spend as much as you can. Some fine binoculars can be had for $200. But true birding bliss comes at a price – a scary price. If birding is big in your life, spend the money and spread the costs well into your bright future, which can be 15 years or more if you choose well and take good care of your investment. After all, if one of those Scarlet Tanagers shows up in full-frontal, you’ll want to get your best view possible.

The Mob, in birder parlance, is a noisy, frenetic assembly of birds ganging up on some common enemy. Chickadees tend to be the kingpins. They begin the assault with an array of call notes. A sharp zeeet comes in response to an approaching predator — a hawk or owl in flight, for example, or a weasel or human walking into the territory. The more familiar chick-a-dee-dee calls are delivered in the presence of a stationary predator. Chickadees vary the rate or urgency of this call or add more dee notes to convey to allies in The Mob the distance or immediacy of the threat.

So a hawk or an owl minding its own business may soon find itself in a maelstrom of chickadees. The Mob swarms and swirls, darts and dives, shouts and scolds in a kind of tactical turf warfare to persuade a predator get lost. Other birds in the woods, when they hear the chickadees going at it, dart in to join the fracas. The Mob is, after all, strength in numbers. It soon includes nuthatches issuing yank-yank calls, Golden-crowned Kinglets delivering short tsee notes and, particularly from southern New England southward, Tufted Titmice and Carolina Wrens repeating raspy scold notes.

Although The Mob is the enemy of the predator, it can be a friend of the birder. A Mob is a songbird magnet, exerting its force on more elusive species deeper in the woods – thrushes, warblers and tanagers, for example – which dart in to investigate the commotion.

You yourself can actually employ The Mob in the great pursuit of birds. The best way is to form Mob of your own. A birder who repeats a soft, wispy spshsh-spshsh-spshsh is imitating some of those avian scold notes. Spishing, or pishing as we also call it, is universal bird lingo for danger. When you spish, songbirds zoom in to investigate. Chickadees often lead the way.

But why would a bird approach The Mob? Why not fly away from danger? For one thing, there may be a bit of altruism going on here, synergy in birds of a feather flocking together. But self-preservation also figures in to The Mob. Owls, of course, hunt by stealth. They surprise their prey, closing the deal with a silent, deadly grasp of the talons. A songbird that might otherwise become owl food would do well to know the predator’s location. So many birders add an owl call – the eerie trill of an eastern screech owl works well – to their spishing.

As with any bird-finding, employ moderation. Excessive spishing can become a form of harassment, so don’t overdo it, especially during the spring breeding season. Once the chickadees respond and the commotion rises, lay off the spishing and enjoy the fruits of The Mob mentality.

They soar and glide with the grace of our most elegant birds. They are content exploring the high seas for fish or picking through Dumpsters for leftovers. They are approachable and audacious. They even offer us an enduring intellectual challenge.

But please do not call them “seagulls.” It is a dismissive term for a gull, even those spending much of their lives at sea. Gulls are living proof that nature is far more diverse than we know. Earth is home to about 50 gull species. They live on every continent in a medley of habitats. Among the few animals surviving closest to the North Pole is the exquisite Ivory Gull. The Kelp Gull is found on the Antarctic Peninsula. In between, the planet downright is “gullible.” We see a dozen or so species here in New England.

So why watch gulls? Better yet, how can you learn to identify them? Well, the thrushes and warblers are gone. If you want color and birdsong you must wait until spring (or go to the Tropics this winter). This is December, after all. Some of us need fresh reasons to get outside. Gulls teach us by example to enjoy winter. They are content to be in the moment, to sit there on the ice (where we can get good looks at them) or to slice the breezes with dignity. Watching them fly, I am in the upper echelons of jealousy.

Here is a better reason to watch gulls now: sometimes they come here from far away – real far away. Ivory Gulls (below) prefer the arctic but have graced the shores of New England. Slaty-backed Gulls live in Asia but at least one wayward bird has visited a sewage treatment plant in inland New Hampshire. And if anything can motivate a birdwatcher, it is a rare visitor, a vagrant with no business being here. Gulls oblige.
In the presence of a rare Black-tailed Gull in Charlotte, Vermont (it should have been in Asia at the time), I overheard birders ascribing to this gull superlatives normally reserved for the likes of the Resplendent Quetzal, regarded as one of the most beautiful birds on the planet. Like Einstein’s theory equating mass and energy  (E=mc²), in the unified field of birdwatching, rarity and beauty are interchangeable and, when combined, exponentially synergistic in effect. An African White-backed Vulture would be drop-dead gorgeous in the White Mountains.

Even so, many birdwatchers don’t bother with gulls. One reason is that they pose some of the greatest identification challenges in all of birding. Many gull species take three or four years before reaching their final adult plumage, which is usually a sharp combination of white, gray and black. During each of their youthful years, many gulls show distinct stages of brown mottling, which can also vary seasonally from summer to winter. The result is that one of these four-year gulls can show eight different plumages. To the novice, it is like identifying snowflakes. But fear not. Here is a five-step approach for the beginning gull-watcher

1. Age Before Beauty – Determine if you’ve got an adult or an immature gull. Adults are clean, showing no mottling other than brownish streaks on the head in winter. Their upper sides are either gray or black and their tails are clean white. Leg color (most often pink or yellow) helps with identification. So start with adults. Here is a quick guide to the adults of our three most common species:
   • Herring Gull has a clean white body and tail with a uniform gray upper-side, black wingtips with white spots, an orange dot on a yellow bill and pink legs.
   • Ring-billed Gull, as an adult, is a smaller version of the Herring Gull except that it has (fittingly) a black ring around its bill and yellow legs.
   • Great Black-backed Gull, the largest gull in the world, is slate black above (not gray like most other gulls) and it is unusual in that its head is clean white in winter. Adult Herring and Ring-billed gulls have mottling on their heads in winter.
2. Learn Basic Feather Morphology – You cannot find unusual gulls, which often appear as immatures, until you know immature plumages of the common gulls. And learning immature plumage requires some basic knowledge of feather arrangement. I’ve recently blogged on this topic. The vast majority of immature gulls you’ll find out there are “first-winter” birds – gulls that hatched out this past spring and are now heading into the first winter of their lives. They’re now basically about six or seven months old. So learn first-winter plumages first. Then worry about successive immature plumages. Here’s an example of some feather morphology with a first-winter Herring Gull. Consult the front of your field guide.
3. Find Your First Odd Gull – Once you know the common species, the odd ones will begin to fly your way. But your best bet for finding them is to get to a winter hotspot. Here in Vermont, that means the Burlington Intervale or the Burlington Waterfront. The Massachusetts coast has attracted everything from Slaty-backed Gull to Ross’s Gull. The commercial Jodfrey State Fish Pier in Gloucester, Massachusetts, and other spots nearby are always worth a winter visit. (I’ve run winter gull workshops there.) Visit and pick out anything that’s not a Herring, Great Black-backed or Ring-billed gull. Iceland Gull and Glaucous Gull can be fairly easy to find at the Fish Pier in Gloucester, for example. Black-headed Gull has put in appearances in recent winters. Among lots of gulls you’ll begin to develop a sense for the unusual.
4. Ask Other Birders for Help – It’s tough to learn this alone. So don’t be bashful. Although there are exceptions, most birdwatchers are willing to share their wisdom.
5. Get a Gull Guide – In your spare time, begin to study those immature plumages in your field guide. Then, once you’re hooked, consider the Peterson’s Guide to Gulls of the Americas by Steve Howell and Jon Dunn.
6. Extra Credit – Crack any field guide and identify the gull pictured at the top of this post. Hint: It’s in breeding plumage. Its winter plumage doesn’t look much this.

So give gulls their due. You need not be like Neil Young, whose nomenclature gaffe we shall forgive (poetic license) when he sang:

“Now I’m livin’ out here on the beach, but those seagulls are still out of reach.”

Birds are much more than wings, of course, so here’s a lesson on feather morphology, more precisely the terms you never bothered to learn from the introductory pages of your field guide.

No matter how different they may appear, all birds have descended from a common ancestor (bird are dinosaurs, by the way, but that is a topic for a future post). So the warbler and the woodpecker, the eagle and the egret all share a common architecture. There is a harmony in those feathers. Let them sing to you.

Consider the species pictured here: Painted Bunting, Herring Gull and Lark Sparrow. The gull, in its first-winter plumage, is a terrifying sight to many birdwatchers. That is because many do not know how to look at a gull, how to approach its identity. To the trained eye, the groups of feathers on this gull are as distinctive as those on the bunting.

The triangle of lemon-lime feathers behind the bunting’s head is the mantle (or upper back). The gull has a similar triangular patch of feathers behind its head, only smaller in this photo. They bleed into a separate patch of feathers on the shoulders, called scapulars, some of which have little black spades in them, extending along the gull’s back. Scapulars are big on gulls, literally, and important for identification of immature gulls.

That band of darker green feather across the bunting’s folded wing make up the greater wing coverts. Coverts are small feathers, often covering the base of larger feathers, such as wing or tail feathers. On the gull I’ve outlined the greater wing. Their appearance is helpful in the identification of many immature gulls.

In the Lark Sparrow, the median wing coverts are tipped in white. Rows of white-tipped wing coverts give rise to a field mark common to many birds, wing bars. Two wing bars most often arise from white tips to the median and greater wing coverts. That Lark Sparrow is also a model for markings on a bird’s head. I’ve labeled them accordingly.

My point is not that you to learn these terms right away. But recognize that these and other feather groups, shared among birds, are like road signs or pavement markings, places we turn, no matter where we are, to understand unfamiliar terrain, to get our bearings. It is one thing to note merely that a sparrow has light and dark stripes on its head. It is far better to note the dark eye-line and lores, the dark auriculars, the lateral chin stripe and pale malar, the rusty lateral crown stripes and the pale supercillium.

That kind of detail is your roadmap to the correct identification. Anything less would be like saying a tree has a bunch of green things at the top.

Most birds gradually replace (molt) some or all of their feathers after the breeding season. Many get a complete makeover, going from ornate to ordinary. It can frustrate birdwatchers who, even in the best of times, can barely find the ring on a ring-necked duck or the yellow on a yellow-bellied sapsucker.

Birds need new feathers this time of year. Take the blackpoll warbler, for example. Males arrived in our coniferous woods back in May, wearing a distinguished black cap (poll) and stripes from the sides of the breast to the flanks. Blackpolls are like angels, their grace and feathers and flight making them radiant without the benefit of color. But over the course of mating and raising young, a songbird’s feathers, essentially dead tissue, become worn, broken, and a bit frayed at the edges. By fall, those feathers would not easily carry a blackpoll to its wintering grounds in South America. So after the rigors of breeding, but before the flight south, they grow a new set.

In many birds, the new feathers resemble the old ones, or some muted version thereof. But in some, like the male blackpoll, the molt seems to create an entirely new bird. In the two photos below note how dull the male’s plumage can become in autumn. Since he no longer needs to appear flashy in order to attract a mate, he might as well become camouflaged in order to avoid predators (and confound birdwatchers). In his field guides, Roger Tory Peterson highlighted the color changes of the molt by including a plate of drab birds titled “Confusing Fall Warblers.”

Compounding the confusion is that many songbirds that hatched this year look nothing like mom and dad. It’s why the common names don’t work for juvenile spotted sandpiper, red-tailed hawk, and female chestnut-sided warbler. And in the fall, cryptic-looking youngsters can outnumber their parents. Just do the math: two adult blackpoll warblers come north to breed; those two plus their four drab young (perhaps even a second clutch of four) are now flitting about and preparing to go south. By the way, in the interest of complete accuracy and full disclosure, that bland blackpoll in the lower photo is actually one of those youngsters; adult males molt to a similar plumage in fall, and adult females, despite their molts, always look this plain. But you get the idea: the male’s transformation is dramatic.

Knowing the magic of the molt explains why, in fall, we never see male bobolinks dressed in black, white, and gold, or tanagers that are actually scarlet. Fear not, the males are still out there. They’ve only traded in their shocking plumage for the drabber duds of winter. The good news is that while they are gone, they will molt yet again and put on their finery for next year’s show.

Discussing shorebirds in August may seem inopportune at first. Sandpipers and plovers are hardly abundant during the nesting season over much of the United States. We tend to enjoy them during the fall migration, when they concentrate along coastlines. But like much of nature, birds don’t always follow the rules we thrust upon them.

For starters, “fall” migration is a misnomer. Some shorebirds fly south as early as July. If you wait until September to discover shorebirds, at least here in the Northeast, you will have missed the bulk of the migration. The coastline is their freeway south, along which they stop to feed and refuel in tidal mudflats and marshes. But if habitat arises inland – flooded farm fields, managed wetlands, or even a reservoir whose water level is lowered to expose the mud below – shorebirds can drop out of migration to feed.

Next, forget about plumage. Most of our most brightly colored adult shorebirds will have molted from their distinctive plumage by late summer, and their young are likewise a study in browns and grays. The black-bellied plover loses it black belly; gone are the spots on the spotted sandpiper; and the purple sandpiper, well, actually, the purple sandpiper is never really purple to begin with. The skilled shorebird observer looks beyond feathers:

Size, Shape, and Posture – Get a sense of size by comparing the bird to a known species nearby. Black bellied plover (almost a foot long) can be a common and useful measuring stick. For shape and posture, is your shorebird bent over with its belly nearly dragging in the mud? Or is it standing tall on long legs? Does it have a slender, elegant neck? Or is your bird like a feathered football with a head?

Bill, Legs, and Plumage – Is the bill stubby, medium, or long? Upturned or downturned (even ever-so-slightly)? Leg length and color can help, but realize that yellow legs can appear dark if they are covered with mud. Some notable plumage does remain on even the drab birds. Note rump color, the presence or absence of wing stripes, and any markings on the breast, head, and back. They can help.

Behavior and Sound – Dowitchers and many other sandpipers feed in mud or shallow water with a steady jabbing motion reminiscent of a sewing machine. Plovers search visually for food. They look around, run, stop, snatch food; look around, run, stop, snatch some more. We don’t use vocalization with shorebirds as much as we do with songbirds, but listen nonetheless. The least sandpiper’s rolling kreeep and the willet’s funny pill will-willet! are diagnostic.

So crack a field guide and start studying your shorebirds. The “fall” migration is upon us.

Image details: The subtle (and not-so-subtle) differences in shorebird characteristics are evident in these images (pictured from top to bottom) of Hudsonian godwit, short-billed dowitcher, purple sandpiper and piping plover.

The Bicknell’s thrush looked like a greedy patron at a salad bar. Stuffed into her bill were a crane fly, a moth, a pupa of some kind, and what looked like a caterpillar. But that apparently wasn’t enough food. She returned later and gathered a heaping plate of earthworm.

Yet the thrush wasn’t being greedy at all. Instead, by collecting all that food, she was offering a vivid lesson in the art of early summer birdwatching: you need not actually see a nest to know that birds are breeding nearby.

Most of the time, songbirds eat their meals on the spot. But many carry food this time of year. In all likelihood, they are bringing it to a prospective mate as part of courtship, to a mate sitting on a nest, or to feed young, either in the nest or newly fledged. And keeping those chicks nourished is a relentless task. Feeding trips are frequent. So a bird carrying food will often lead you to its nest.

But be aware that some of what goes in must also come out. A songbird flying with what appears to be a small white balloon in its bill is carrying a “fecal sac” – a “diaper” of nestling feces being removed from the nest and dropped out of sight. It is a clever way to keep the nest clean, free of bacteria, and less vulnerable to predators attracted by the odors.

For other birds, however, evidence of nesting isn’t so subtle. “Duck and cover” was a Cold War drill for generations of school children learning to fear the bomb. But nothing gives it new meaning like a northern goshawk.

I once trespassed onto the territory of a goshawk pair. One of the adults, shouting a rapid and raspy “kehk-kehk-kehk-kehkkehk,” came at me like a missile. Ordinarily, when an angry critter zooms my way, I prefer to stand my ground and enjoy the show. Not so with a goshawk. I ducked, covered, turned, and fled like a snowshoe hare. The enraged hawk passed close enough for me to feel wind from its wings. There could be no doubt about a nest nearby.

Other birds, presented with an intruder near the nest, prefer deception over aggression. The killdeer, trying to appear as easy prey, will feign a broken wing and limp away in order to distract a prospective predator from its nest. An ovenbird once did a similar ruse for me. Other species may scoot along the forest floor like a small mammal to divert the attention of a predator. We call these tricks distraction displays.

But there can be no fakery in a bill full of food. The Bicknell’s thrush had mouths to feed. So I kept watching. She vanished into the bough of a balsam fir, and I could hear the chirps of hungry young. From a safe distance, I was able to watch her shove her haul of earthworms down their throats. Now if only northern goshawks would calm down and practice a little détente.

First, recognize that many LBBs are streaked or specked on the breast, belly and sides. Many are also roughly the same size – smaller than an American robin. So focus less on plumage and size. Consider the bird’s shape, bill, behavior and habitat. I’ll illustrate with four examples.

LBB No. 1, on top, is somewhat elongated and sort-of pot-bellied. It is relatively slim below the neck, particularly compared to LBB Nos. 2 and 3. Its bill is longish for a songbird. I photographed this bird in the woods, which is where it prefers to nest.

LBB No. 2’s proportions are relatively compact. It is shaped more like a football (with a tail) than LBB No. 1. It has a thicker neck. And its bill is conical, stubbier than LBB No. 1’s bill. I photographed this bird in shrubs near a clearing. You won’t find LBB No. 2 nesting in the woods.

LBB No. 3 is similar to LBB No. 2, with the same overall proportions and bill. Photographed on turf during spring migration, it also nests in open, scrubby areas, never in the woods. Your gut might be telling you by now that LBB Nos. 2 and 3 are sparrows.

LBB No. 4 is an oddball. Although this photo doesn’t capture its posture well, this bird is long and thin, particularly around the head and tail. Although it resembles a sparrow, that bill alone betrays it a sparrow impersonator. And no photo will show one of the best clues to its identity: it has a silly walk, bobbing its head forward and back with every step. All other LBBs here hop rather than walk. It is also notable that this LBB is on grass (near a lighthouse in Maine). It nests in tundra and other open areas.

So what have we got? LBB No. 1 is a hermit thrush. Its rusty tail helps distinguish it from other closely related woodland thrushes. LBB No. 2 is a Lincoln’s sparrow. The ultra-fine streaking below is a great mark on this species; if they have them, most sparrows show wider streaks than this. LBB No. 3 is a clay-colored sparrow. One hint on sparrow identification is to note first whether your bird is streaked or clean below. Then look at the face for distinctive markings. LBB No. 4 is an American pipit. No self-respecting pipit will be found in the shrubs among sparrows.

And if you’re still struggling, fear not. You are free to call them Little Brown Birds. At the very least, you can be sure they are not ducks.

A crucial skill in birdwatching is learning to get a full, meticulous look at a bird. A Great Blue Heron wading in a pond is easy. The difference between a woodpecker and a Willet is a no-brainer. But songbirds — flycatchers, vireos, thrushes, warblers, sparrows and other lyrical gems — won’t always be as distinctive or cooperative. They can present formidable challenges to the novice observer. So a new birder must do some homework, make the best use of every glimpse, every bit of information gathered, and record a complete mental image before turning to the field guide.

First note overall shape and posture. Is the bird plump like a thrush or slender like a cuckoo? Head and tail proportions can help. Flycatchers look as if their heads are sort of squashed down onto their shoulders. Vireos have necks. Even within groups, shape can be distinctive. Song Sparrow has a relatively long tail that flops around a bit when the bird’s in flight; Savannah Sparrow has a short tail. How about posture? Is the songbird bent forward like a warbler? Or is it perched upright and still like a flycatcher?

Behavior helps. Is your bird launching from a perch, catching an insect and returning to its perch, which is common among those flycatchers, or is it hopping through the foliage and feeding as it goes, like those warblers and vireos. An American Pipit might look like a streaky sparrow, but it has a silly walk; sparrows hop. (The pipit’s slender bill also exposes it as a sparrow impostor.)

When noting color and other marks, be specific about extent and location. Sure, most everyone knows an American Robin has a reddish-orange breast. But how extensive is the red plumage? Does it continue up the throat and under the tail? Noting these kinds of details — and knowing when to look for them — can be the difference between a good birder and a great birder.

Field marks, of course, are vital evidence of a bird’s identity. But learn some rules and generalizations for specific groups of birds. Some vireos have wing bars; others don’t. Most North American owl species have yellow eyes; four species have black eyes. Some sparrows are streaked below; others are clean. Least Sandpiper has yellow legs; its close relatives have black legs. These kinds of subtleties — and knowing when to look for them — can help you clinch a bird’s identity. For many of us, it’s second nature: you want to tell American Golden Plover from Black-bellied Plover in flight? Look for the black axillaries (“wingpits”). Bohemian Waxwings from Cedar Waxwings? Look for the rusty undertail coverts. We don’t think twice about doing this sort of thing.

Most field guides include an introduction to the plumage structure of birds. It is vital reading – even for advanced birdwatchers.  So pay attention to detail. After all, if that confusing warbler in the sugar maple had a bit of  black on the upper breast, a hooded look and no white eye-ring, you would have identified it as a Mourning Warbler instead of a Nashville Warbler. I extracted that image of a Mourning Warbler from a video clip I got during one of my Warbler Weekend outings at Highland Lodge, in Greensboro, Vermont.

A repeated, soft wispy “spshsh-spshsh-spshsh” is bird parlance for danger. A birder spishing is imitating the scolding or warning notes that some songbirds utter to alert others of a lurking predator. It’s a universal alarm call. So when you spish, songbirds often pop into your view to investigate.

Consider the encounter I had during a recent winter bird count on Long Island. While bushwhacking through scrubby oak-pine woodlands, the only bird note I heard was the thin high tseep of a white-throated sparrow. The woods were otherwise silent. Vacant. But I suspected otherwise. So I stopped and spished.

“Spshsh-spshsh-spshsh-spshsh. Psssp-psssp-psssp-psssp-psssp. Spshsh-spshsh-spshsh-spshsh.”

Two white-throated sparrows jumped into view from a tangle of catbrier. Then several more. An eastern towhee belted out a plucky reeEEP! I kept spishing. A northern cardinal emerged and uttered its short, bright peek note. Two hermit thrushes popped onto a white oak branch, flicked their wings and repeated a couple of soft chuck calls.

But the concert was only beginning.

“Spshsh-spshsh-spshsh-spshsh. Psssp-psssp-psssp-psssp-psssp. Spshsh-spshsh-spshsh-spshsh.”

I enhanced the ruse by adding the rolling whistle of an eastern screech owl. Soon the trees and brambles became alive with more birds: a red-bellied woodpecker, a half-dozen black-capped chickadees, several tufted titmouse, a winter wren, three more towhees, two brown thrashers, a gray catbird, a northern mockingbird and a few yellow-rumped warblers.

The owl call, combined with spishing, really grabbed their attention. The reason? Owls hunt songbirds by stealth. In silent, deadly flight they surprise their prey, closing the deal with a well-practiced grasp of the talons. Yet, the whistle of the screech owl actually attracts the other birds trying to determine the location of their predator. A songbird that might otherwise become owl food can avoid danger if it knows where the owl is perched.

Your best ally in this ruse to attract songbirds is the black-capped chickadee. The chickadee is often the first species to respond to spishing or to the whistle of the screech owl. Chickadees will issue a high-intensity zeeet call in response to a rapidly approaching predator, such as a hawk or owl in flight, or a dog or human walking into their territory. They will deliver the more familiar chick-a-dee-dee alerts in the presence of a stationary predator. Researchers have concluded that chickadees vary the rate or urgency of this call or add more dee notes to convey the distance or immediacy of the threat.

Chickadees approach the scene of perceived danger because they recognize strength and safety in numbers. They respond to your spishing with their own warning calls; a mob of them will converge to harass a perched hawk or owl, scolding it with notes or even dive-bombing the raptor to harass it out of the territory. Other songbird species are likely to notice and join the commotion.

Incidentally, danger isn’t the only thing that gets birds calling. They call out during feeding and courtship. Night-flying songbirds call to keep the flock together in the dark. Some birds that herd together during breeding, such as gulls and gannets, use call notes to help mates keep track of each other.

You can try call notes on your own at home. Head outside in the snow, find a flock of black-capped chickadees and begin spishing. Be patient. It may take a few minutes to get the gang together. Approach slowly. Avoid sudden, jerky movement. The chickadee chatter will build, and soon hairy woodpecker, white-breasted or red-breasted nuthatch, tufted titmouse or even a golden-crowned kinglet may join the mob.

As with any bird-questing technique, excessive spishing can become a form of harassment, so don’t overdo it — especially during the spring breeding season. Once the birds respond, lay off the spishing and enjoy the show.

Then invite the neighbors over to explain what you’ve been doing. That will dispel rumors you’ve lost your marbles and are hissing at trees.