Bill Size and Shape

One of my favorite things to do, during migration season is to identify birds.  Many aspects of bird watching combine to make this the world’s number one hobby; the hunt through the binoculars for that wind-blown leaf you thought was a bird;  the sudden realization that you’re facing the wrong direction in a valley; following a song for an entire afternoon just to get a glimpse of that fellow who sings his heart out. 

When I do finally see that special bird, I have to take quick mental notes on size, color, foot type (if I see a bird feeding), bill type, and behaviors.  Although behavior is a really big part of identification, I enjoy using bill type as a guide for those really tough ones.  This is especially true when you consider that many species depend mostly on a specific food for survival.  Whether it feeds on seeds, insects, nectar, or other animals, its bill will be specially adapted for feeding.

Members of the parrot family have beaks that are designed for gripping and cracking seeds and nuts.  (photo: Leigh French)

Seedeaters need to have a bill that is strong enough to crack through the thick hard hulls to get to the meaty fruit inside.  Their bills are often thick and arrow shaped having hard ridges to aide in grip, like a wrench.  Parrots are a great example of this.  Their bills are very thick and their upper mandible has serrations on its underside, out near the tip, so that they can grip nuts and crack them.  Also, cardinals have a thick, strong bill for smaller seeds.

Shorebirds are a wonderful example of diversity within a habitat.  Gulls and terns have bills adapted for fishing.  They dive into the water from the air or from floating on the water. 

Roseate Spoonbills have a bill shaped for shoveling around in the lake bottom debris for their food. (photo: Gay Schroer)

Some Ducks and wading birds have a specialized bill for shoveling around in the water for invertebrates. 

This Scarlet Ibis has a very specialized beak for probing for food in soft mud and under plants (photo: Gay Schroer)

Birds like the sandpipers, oystercatchers, godwits, turnstones, and plovers have bills that are shaped for finding invertebrates that have tunneled into the sand or mud.  Their bill is sort of shaped like the prey for which they forage. 

Herons and egrets use their bill as a spear.

This Great Blue Heron uses his bill as a spear and then swallows the fish whole (photo: Gay Schroer

…whereas this Yellow-crowned Night Heron snatches his preferred diet of crayfish with his long pointed bill

…and then turns it, pinchers side out, and crushes it with the powerful upper portion of his bill before swallowing it

Moving away from the shore, there are other smaller birds that flit about after tiny gnats and flies.  These birds have small bills and are a bit more difficult to identify because they are usually small and fast.  These are typically gnatcatchers and flycatchers. 

Prothonotary Warblers have small thin bills for catching insects and snails which they pry out of their hiding places

Ruby-crowned Kinglets are such tiny little birds and they are the most difficult for me to see clearly.  That’s when I listen to any calls or songs they may be making.  Woodpeckers have a bill that is like a chisel.  They bang away at trees looking for insects crawling under the bark and inside the wood.

Finally, I think crows and ravens are a good transition into birds of prey.  They are very adept and intelligent.  They hammer and poke and tear and pull their food.

Meat eaters are probably more diverse because they may feed on certain animals based on their habitat.  Owls, hawks, and eagles have bills that are great for tearing meat.

The Eurasian Eagle Owl has a beak that is supremely well adapted for tearing meat (photo: Gay Schroer)

So, when you are having trouble narrowing down that bird species, perhaps you can get a good look at the bill to figure out a bit about it.

The next time you visit the World Bird Sanctuary, pay particular attention to the different beak shapes that you will see on our display birds and the birds that visit our bird feeders.  Try to guess what each bird’s preferred food would be.

Submitted by W. Leigh French, World Bird Sanctuary Naturalist

The American White Ibis

For as long as I can remember, one of my favorite birds has been the American White Ibis (Eudocimis albus).  I wouldn't be able to explain why I like them so much--I just know that I do.

The American White Ibis is mostly white with black primaries visible during flight (photo: the Wikipedia files)

As you have probably guessed, the American White Ibis is white--well, mostly.  It does have black primary feathers on its wings.  Its long legs and webbed toes (but not quite as webbed as a duck) are pale orange.  The same is true for its face.  During the breeding season (usually June and July), though this pale orange turns into a striking bright pink. 

American White Ibis’ have a very long bill like an egret, heron, or stork, but unlike those birds the White Ibis' bill is curved and very sensitive to movement.  This is important because of how they find their food.  They use their bill to grab small fish, amphibians, insects, and mostly small crustaceans.  They can get food directly out of shallow water or even in shallow sand or mud.  If there is vegetation in the water the Ibis will slowly walk through and stomp on the vegetation to get its prey to come out. 

The American White Ibis gather in huge colonies during the breeding season.  They do not mate for life, but every year, after a pair bonds, the male will bring sticks and vegetation to the female in a tree and then she will construct the nest.  They usually have 4 eggs, but sometimes less.  After the chicks hatch they usually leave the nest within just 2 weeks. 

The American White Ibis has been known to interbreed with the Scarlet Ibis in areas where their territories overlap (photo: Gay Schroer)

You can find these pristine looking birds in and around the Caribbean along the coasts of southern North America and South America and many islands along these coasts.  They are very abundant in the wild and are very often seen in Florida.  Their breeding range runs along the Gulf and Atlantic coast of North America, and along the coasts of Mexico and Central America.  Populations in northern Venezuela overlap with the range of the Scarlet Ibis (Eudocimus ruber), and in some instances they have been known to interbreed with these vibrantly colored birds.  There is some speculation in the professional community that these two birds should be classified as a single species.

There are currently no conservation efforts in place to help these birds because they are doing so well on their own in the wild.  They are classified as a species of "least concern" by the IUCN (International Union for Conservation of Nature).  However, the plans to restore the Florida Everglades should benefit these wonderful creatures immensely.

Submitted by Mike Cerutti, World Bird Sanctuary Naturalist/Trainer