Someone new to birding asked here on a recent Sunday morning if anyone could offer some tips about bird identification -- what should you look for if you only have a brief glimpse to take in details? Our regular Dawn Chorus host, lineatus, responded that body shape was the best place to start. I agree with that 100%. And once you get a handle on basic body shapes, birds' bills (or beaks) can also provide some guidance. Join me in taking a look at some bills that can help tell this tale.
Since eating food is a basic element of life for every species, it will come as no surprise that birds have evolved to take advantage of the food sources in their habitats. And those food sources, in turn, have dictated the evolutionary processes that produce the bills we see in birds -- bills that are exquisitely designed to acquire the food they need to survive. In short, bird bills have jobs -- they skim, they probe, they spear, they scavenge -- they do what each species needs them to do to complete the all-important task of transferring food into energy.
Like overall body shapes, bird bills can help you identify birds and at least minimally narrow the range of possibilities when you see a bird in the field. Just last weekend, I was photographing birds in poor light in an area that was rife with warblers. Looking at my photos later, the silhouette images I saw told me immediately that these were no warblers. Even though the images were dark, the conical bills told me right away that what I'd captured were some sort of seed eaters and not warblers. Bills can be a really useful ID tool even in poor light.
To see what I mean, I've posted a chart below (taken from Wikipedia) that shows the differences between bills and identifies the main job those bills do. Following that are some photos I've taken that illustrate different birds with these bill types. I hope all the Dawn Chorus folks with photos to share that further show these bill differences will join in and share some examples!
Following the descriptions used in the chart, here are some examples:
Everyone knows this favorite nectar feeder. Hummingbirds have a long tongue inside that very long bill that allow them to take in nectar (and insects, by the way) very efficiently.
Pelicans dip, scoop and filter whatever they catch. Think kitchen colander with the pasta you just poured into it. These American Pelicans feed often in groups and motor along the water at a pretty good clip, dipping and bobbing. They look like giant sewing machines on steroids.
So prevalent are the insect-catching birds, there's a whole class of them in the birding world, the aptly-named Flycatchers. (Is class the right word, biology-wise? Or is it family? Yes, I'm asking you, matching mole:)
These birds regularly perch and then flit in the air and re-perch in the same spot. They're basically jumping out to catch insects in the air. (Flycatchers aren't the only group that eat insects; many, many birds do.)
Here's the familiar Black Phoebe, a favorite Flycatcher.
And a Say's Phoebe, another Flycatcher, giving another good look at that bill.
Here's another in the family, a Pacific Slope Flycatcher. Notice that the shape of their bills is very similar. Optimized for catching insects.
And here's an insect-eater probably most familiar to all, the Northern Mockingbird.
Grain or seed-eating birds have conical bills that are short and powerful for purposes of grinding. Think of the difference between your front teeth and incisors, which are great for biting and tearing, and your molars, which you need to grind and chew. Seed-eating birds need bills that act as molars. Needless to say, these seed eaters are the birds you see at feeders.
The American Goldfinch is common at feeders and they enjoy thistle seed more than anything else.
The House Finch is perhaps the most common seed-eating bird in the United States and is a regular at bird feeders. You can see how its bill is short and conical, perfect for crushing seeds.
If you've ever seen a scythe, you know it's a long, curved tool that is swiped side-to-side to mow or cut grain. And that action perfectly describes birds that use their bills with that exact action to find food. The best example is the American Avocet with its long, upturned bill.
Avocets walk slowly through shallow water, sweeping their heads from side-to-side, grabbing tasty morsels along the way.
If you look at the chart up above, you see a long pointed bill for the Aerial Fishing example. That long and pointy bill is attached to a short, powerful body designed to perch above and perform a sweeping dive into water to seize fish and other prey. The best example of this bill is the kingfisher, and in this photo, it's a Belted Kingfisher.
Birds with probing bills use them to find food below the surface at varying depths. The longer the bill, the deeper they probe. A few examples:
A Greater Yellowlegs
A Marbled Godwit
A Long-billed Curlew, with sort of the grand-daddy of long, probing bills.
Keeping with the comparison to your own teeth that I mentioned above, where seed eaters need a bill that grinds like molars, raptors need bills that pierce and tear, since their diet is mostly small mammals and reptiles.
An American Kestrel
Last, a Peregrine Falcon that provides a good, close-up look of a bill that's truly designed for tearing. Ouch.
These are but a few examples of different bills. I'm going to stop now and invite others to post their own photos that show more examples of these and other bills I didn't even touch on -- the scavenging bills, the chiseling bills -- it goes on with many more examples.
The point is, beyond overall body shape as perhaps the first filter for identifying birds, knowing bill shapes can be the next most helpful clue for narrowing it down. Is that bird on the telephone wire a starling or a kestrel? Body shape and bill will help you distinguish the difference.
Please share your own photos and any comments about bills (or anything else) you'd care to share!