How closely and carefully do you need to look at a bird to identify it? Having a live bird in hand would be ideal, but you can learn a lot even from a distance. Is the bird about the size of a crow, or closer to the size of a sparrow? How large is the bill in relation to the rest of the head? These characteristics can often distinguish one bird species from another. Join Chris Wood and Jessie Barry as they put their knowledge of external avian anatomy into practice in the field.
This video is part of our 4-part Inside Birding series. Each roughly 10-minute video guides you through the 4 basic keys to bird identification with clear instruction and examples. The four videos in the series are:
Would you like to learn more about using size and shape to identify more birds in your area? Bird Academys online courses let enthusiasts of all levels learn at their own pace. You can browse our course catalog to find the perfect online learning resource for yourself. Be a better birder today: View course catalog
Judge against birds in the same field of view
If you can compare one bird directly to another, your estimate of size will become much more accurate. You can utilize the species you recognize to distinguish between groups of different species when you come across them.
For example, when observing an unfamiliar gull, you may begin to notice that it is larger than the nearby, more familiar bird, such as a Ring-billed Gull. A key identification method for certain bird groups, such as shorebirds, seabirds, and waterfowl, is to use a known bird as a ruler.
- For flying birds, like mixed flocks of grackles, blackbirds, cowbirds, and starlings, size and shape can be very helpful. Look for the European Starlings in this picture, which are small-sized, with pointed wings, amidst the Common Grackles with long tails. Photo by Robert Baker/PFW.
- A mixed group of gulls can be a real advantage. Here, the few Herring Gulls behind the massive Great Black-backed Gulls appear almost insignificant. Nearly invisible in the front row is the European Black-headed Gull, a rare species. Photo by Byard Miller via Birdshare.
- To locate all species concealed in a large flock, use size and shape. Amid these orange-billed Royal Terns are some smaller Sandwich Terns. Several smaller Laughing Gulls can be seen to its right of the enormous Herring Gull in the background. Photo by Shorebird 777 via Birdshare.
- Acquire the ability to identify a few familiar birds, then measure unfamiliar birds using their sizes. These three common shorebirds are a great place to start: the small Sanderling, the tall Willet, and the colorful Ruddy Turnstone. Photo by Byard Miller via Birdshare.
Measure the bird against itself
This is the most effective method for identifying birds based on their size. A solitary bird’s size is difficult to estimate, and its shape can be confusing due to its peculiar posture. However, you can always measure the bird’s vital componentsits wings, bill, tail, and legsagainst its actual body.
Consider details such as the length of the bill in relation to the head; this is helpful in distinguishing between the Greater and Lesser yellowlegs and the Downy and Hairy woodpeckers, among other species that can be difficult to identify. When identifying Cooper’s Hawks from Sharp-shinned Hawks in flight, one can determine the size of the head in relation to the rest of the body.
Make it a habit to use the bird itself as a ruler, and you’ll be astounded by how much data you can extract from every angle. A good place to start would be measuring the length of the legs, neck, tail, and primary feathers of the wings, as well as the distance the tail extends past the body.
Apply your size & shape skills to the parts of a bird
Once you’ve noted the general size and form of a bird, you can still refine your identification. Focus on the dimensions and forms of specific body parts. Here are some hints about the bird’s lifestyle, including where it lives, what it eats, and how it flies.
Let’s start with the bill, an all-purpose instrument that can be used as a bullhorn, pliers, knitting needles, knife, and fork, among other things. The thick, conical nut-smasher of a finch is distinctly different from the broad, flat, bug-snatching bill of a flycatcher. Take note of the Northern Flickers’ slightly downward-curving bills in your backyard. Although the shape of a woodpecker’s bill is unusual, it is ideal for a bird that burrows beneath the earth in search of ants, as flickers frequently do.
Though tail and wing shapes are also significant, bills are a crucial identifying cue. If you look closely, even seemingly insignificant variations in body shape, neck length, and head shape can provide insightful information.
Observing details such as these can assist you in avoiding common identification errors. Many bird watchers have been duped into believing that an Ovenbird, a common eastern warbler, is a thrush. The field marks, which are warm brown above and heavily streaked below with a sharp white eyering, are unquestionably thrush-like. However, if you focus on overall size and shape rather than specific field marks, you’ll notice the warbler’s body plan: a compact, plump body, short tail and wings, and a thin, pointed bill that is used to catch insects.
FAQ
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