Foundations of Field ID: Behavior
How the way a bird moves and acts can reveal its identity
Welcome to the birdy side of the internet! This week’s edition is full of insights to help you become a more confident, field-ready birder. From our Birding Tip on tackling confusing mixed-species flocks to our latest Foundations of Field ID installment on bird behavior, there’s plenty to build on. But first, a look back at a legendary raptor sighting that set the birding world abuzz.
This Week in Birding History: A Great, Black Hawk
August 6, 2018 —Seven years ago this week, Christine O’Leary Murphy lit up the birding world with a photo of a Great Black Hawk in Biddeford, Maine. A large Neotropical raptor, the Great Black Hawk is typically found from Mexico through Central and South America. So was this bird a first for the United States? Yes… sort of.
Just over three months earlier, a juvenile Great Black Hawk in fresh plumage had been photo-documented on South Padre Island, Texas—marking the first accepted record of the species north of Mexico (see Editor’s note). Amazingly, thanks to detailed photographic comparisons of the bird’s plumage, it was later confirmed that the Texas and Maine birds were one and the same!
The now-famous hawk made national headlines and drew thousands of birders to southern Maine—some traveling from as far away as California—for a chance to see this tropical species. While the broad strokes of the story are well documented in news reports and birding media, two lesser-known footnotes stand out:
First, Doug Hitchcox’s eBird checklist marked the first time a Great Black Hawk and a Common Eider were ever recorded together—a surreal pairing that underscored just how out of place the hawk was.
Second, the Maine State Museum, in partnership with Friends of Deering Oaks, later installed a bronze statue and interpretive sign in Portland’s Deering Oaks Park, where the hawk famously spent three months. From the tropics to the frozen branches of a New England city park in winter, the Great Black Hawk’s improbable journey captivated birders and non-birders alike—a rare case of a vagrant bird turning into a local legend.
Editor’s note: While this bird technically accounts for the first and second accepted records of a Great Black Hawk north of Mexico, unaccepted sightings date back to the 1970s on Virginia Key near Miami, Florida. Lacking confirmed provenance, those early reports were not accepted by the Florida records committee. The Tropical Audubon Society offers an excellent primer on this history, and many additional sightings have occurred since, as recently as 2015.
Birding Tip: Tackling Confusable Flocks
Last week, we discussed estimating flock sizes when encountering large or cumbersome groups of birds. We noted that it’s often easiest to count the most common species first, then move on to the lesser abundant or rare ones. It sounds simple—however, in the field, it’s often anything but.
All bird flocks pose their own challenges, but some are more forgiving than others. If you’re just getting started, trying to learn the process, sorting distant shorebirds through a shimmering heat haze can be overwhelming. Beginning with a raft of ducks may offer a gentler entry point, as ducks often have more distinct field marks or behaviors (see this week’s Foundations of Field ID) that are easier to spot—even at a distance.
When faced with a mixed-species flock, success comes from quiet focus and layered observation. For example, sorting out peeps (small sandpipers) often hinges on subtle traits like leg color, bill shape, or body posture. Focus first on birds in the best light and closest range. Study those individuals carefully. Once you get a mental snapshot of the key field marks, scanning the rest of the flock becomes much easier—even under less optimal viewing conditions.
Working through a flock of Larus gulls? Make multiple passes, each with a different focus:
Pass 1: Look at size and shape—bill length, head shape, body proportions. This can quickly separate larger American Herring Gulls from slimmer Lesser Black-backed or smaller Ring-billed Gulls.
Pass 2: Assess plumage—mantle tone (a gull’s gray back), primary tips (are they black, gray, or white), feather wear. This helps identify age classes and spot uncommon species.
Pass 3: Tune into fine details—perhaps the raspberry-pink orbital ring of a Kumlien’s Iceland Gull largely obscured by other birds or the bicolored bill of a young Glaucous Gull.
Pass 4: Observe behavior—watch which birds prefer shoreline foraging versus loafing on piers, and note unique feeding styles.
By systematically revisiting the flock with these layered observations, you’ll steadily peel back the confusion and arrive at accurate counts and confident IDs.
In large, mixed blackbird flocks—grackles, cowbirds, starlings, and blackbirds of various species—the pace can feel frantic. These birds shift quickly and often look similar in poor light. Here, behavior is your ally. On the ground, grackles strut with longer steps, cowbirds tail others closely, and starlings frequently cluster. When the flock flushes, flight styles become telling, aiding in the ID (see Pro tip for an example). And don’t forget to listen—calls are often the clearest clue of all.
Mastering mixed flocks takes time. But a methodical, multi-layered approach turns chaos into confidence. Whether you’re facing gull roosts, blackbird swirls, or a mudflat of sandy shorebirds, patient observation and repeat passes will move you from confusion to clarity—and from frustration to fascination.
Pro tip: Rusty Blackbirds have undergone one of the steepest declines of any North American songbird over the past 50 years—so spotting them matters. Look for their slightly slower, more buoyant flight compared to Red-winged Blackbirds, and note their relatively long tail, pointed head, and streamlined shape.
Foundations of Field ID: Behavior
Welcome back to Birding University’s four-part series on the foundations of bird identification. After covering size and shape, then color patterns, this month we focus on behavior—the unique ways birds move and live that can help reveal their identities.
Understanding behavior can be as revealing as spotting a distinct field mark. Birds don’t just look different—they act differently. Recognizing how they perch, fly, move, feed, and engage with their environment is a powerful ID tool, especially when other clues aren’t readily visible. For example, some species forage quietly on the ground, while others dart acrobatically through the air. These habits often are often a first filter to help separate birds of similar size, shape, or color—like sparrows from brown-colored swallows.
Because behavior can reveal a bird’s identity from a distance or in poor light, it’s a valuable skill to develop. Before raising your binoculars, note how the bird holds itself, moves, and interacts with its surroundings. Is it alone or in a group? Does it nervously flick its wings or periodically pump its tail? Patience is key—take time to observe. The longer you watch, the more distinctive motions and patterns you’ll notice, deepening your connection with the birds. Not every behavior that clinches an ID appears immediately. Build up your mental rolodex of behaviors over time. And watch your common species a lot, they will be your foundation!
We’ll explore behavior in more depth across future Birding University content, but for now, here are a few simple behavioral cues you can start using in the field today.
Movement
How a bird moves can be just as revealing as how it looks. Much like recognizing a friend from across the street by their walk or gestures, birds often give themselves away through signature movements. Some hop steadily along the ground; others take deliberate steps. Some dart quickly through branches; others glide effortlessly through open air. Even on water, a bird’s swimming style can offer valuable clues. Try putting these behaviors into broad categories, using familiar terms. While we want to avoid overly anthropomorphizing, describing a bird as sluggish, nervous, deliberate, or frantic can help you capture and recall its behavior more effectively.
Flight Style
How a bird moves through the air—whether it soars, glides, flaps, or darts—can offer strong clues to its identity. Woodpeckers bounce in an undulating pattern, while finches often flap in short bursts with a similar, bouncy rhythm. Swallows and swifts are agile, darting with fluid or rapid wingbeats, respectively. Gulls and raptors soar with broad wings, while ducks and alcids power straight ahead with constant, whirring wingbeats. Herons and cranes fly gracefully with slow, deep flaps—herons with tucked necks, cranes with necks outstretched. These motion signatures, once familiar, can be as telling as plumage or song. It’s why hawkwatchers can identify raptors soaring on distant horizons, giving names to birds others see only as tiny specks.
Feeding Behavior
A bird’s bill shape reveals much about its identity—and so does how it feeds. Of course, these are closely linked. Some species snatch insects in flight; others probe bark or sift through leaf litter. Seed-eaters often sit quietly cracking food with large bills, while shorebirds like Sanderlings dash across beaches chasing prey left by relentless waves. Closely related species may have unique feeding styles that aid identification even when plumage is hard to see.
For example, some ducks skim plant matter at the surface; others tip forward to feed just below—classic “duck butts.” Diving species disappear entirely, pursuing submerged vegetation, insects, fish, or mollusks. Knowing how a duck feeds helps us break it down into simple groups of species, for instance, dabbler or divers.
But we can take this one step further (we always can). For instance, how a duck dives can offer even more ID clues: most diving ducks, like scaup, propel themselves underwater using only their feet, with wings tucked in. Others—such as most sea ducks—use both wings and feet, often visibly engaged during the dive. So if all you catch is a glimpse of a duck mid-dive through your scope, but you noticed a wing flick, you might be looking at something like a Long-tailed Duck surfacing moments later.
Similarly, aerial feeding behavior helps identify groups of flycatchers. Flycatching—darting from a perch to snatch insects mid-air before returning—is a hallmark of the Tyrannidae family. While waxwings, warblers, kinglets, and hummingbirds also flycatch, consistent use usually indicates a true flycatcher.
Now, not all flycatchers behave the same. Pewees often return repeatedly to the same perch; Empidonax flycatchers may move more between perches, repositioning after each foraging attempt. Perch choice also differs: kingbirds and pewees usually prefer high, exposed spots on bare branches; Myiarchus flycatchers stay deeper in foliage. These behaviors help refine IDs.
If you’re not ready to dive into these details yet, don’t worry—they come with time. Simply recognizing a bird as a diving duck or flycatcher, combined with size, shape, color, and habitat, can guide you toward identification—even of a silent bird.
Social Behavior and Flocking
Birds also differ socially. Some species are solitary or in pairs; others flock in the hundreds or thousands. Knowing if a species tends to be gregarious or solitary—and how it behaves in groups—is another valuable clue. Note—Seasonal shifts influence flocking: during breeding, many species are alone, in pairs, or small family groups or breeding colonies; outside breeding, even solitary species often form loose flocks during feeding or migration.
Small Behavioral Cues Offer Big Insights
Watch for repeated motions like subtle wing flicks, tail pumps, or head bobs. Ruby-crowned Kinglets constantly flick their wings, setting them apart from similar greenish songbirds like warblers or vireos. Eastern Phoebes, American Pipits, and Palm Warblers frequently pump or bob their tails, a famous behavioral field mark. Even tail pump style matters—slow or fast, up or down. These subtle but consistent “tells” often reveal a species or at least get you closer to a final ID.
Practice & Progress
Spend time simply watching birds wherever you’re comfortable. Observe posture, movement, feeding, and interactions. Describe what you see to yourself or a partner. Or sketch! When watching a new bird, ask: How is it perched? How does it move? What feeding style does it use? Is it alone or in a group? Any repeated motions? Behavior adds a powerful layer to size, shape, and color. Sometimes it’s the first clue that draws your attention and leads to confident ID.
What’s Next?
Next month, we’ll explore habitat—how the places birds choose help you identify them more accurately. Until then, enjoy watching, listening to, and learning from the remarkable ways birds move through their world.
Weekly Poll
What behavior has helped you ID a bird? Maybe a tern diving, a phoebe tail-pumping, or a nuthatch creeping headfirst down a tree—tell us below!
Thanks for Reading
Thanks for reading! We appreciate you sticking with us through this journey. Stay tuned—this month we have some big announcements coming, including a long-developed preview of paid content and a possible shift in the format of our weekly newsletter. Exciting things ahead!
* Please visit Phil Stollsteimer Photography for more amazing bird photography.