White IbisThe white ibis is one of four aquatic wading birds that breed in North America. (Photo David A. Murray)

The tropical regions of the world are home to many beautiful and interesting birds. Many of the aquatic bird species are large, colorful birds, and due to their size are highly visible and easily found.

One of these tropical families of aquatic birds is the Threskiornith i dae . This family contains thirty-three different species, of which four species breed in North America. One of the four species that breed in North America is the beautiful white ibis.

The white ibis is a reasonably large bird and stands over two feet tall, with an impressive wingspan of over three feet. The body size and shape is similar to that of the great blue heron, but otherwise, the white ibis is distinctively different.

A white ibis has many unique and recognizable characteristics. The feathers of the adult bird are vivid white in color, with the exception of a small black patch located on the tips of the wings; however, these black patches are visible only when the bird is in flight.

An immature bird will vary in color from predominantly brown and white to a combination of mottled and streaked brownish feathers. This can vary considerably depending upon the time of year and the age of the bird.

Other highly visible characteristics of the adult white ibis are the featherless or bare face, and unique bill. Both the face and bill are a slate-gray color, except during the breeding season when they turn to a vivid orange-red color. The legs of the adult white ibis also turn from slate-gray to orange-red during breeding. The bird's bill is also unusual in that its long slender shape curves downward.

White ibis, as previously mentioned, are one of four species that breed in North America. Their range is predominantly along the coasts of North Carolina south to Florida, as well as along the coast of Texas. However, over the last several years, this species has expanded its range; and now, ibis range as far north as the Virginia and New Jersey coasts. This expansion of their range could be a result of the shorter and milder winter conditions that have prevailed over the last decade.

Along with coastal salt marshes, the preferred habitat of the white ibis is mudflats, swamps, mangroves, and lagoons. As with most aquatic wading birds, any source of shallow water that offers food is a suitable habitat.

Most of the aquatic wading birds feed on small fish as their primary food source. However, the white ibis prefers eating crabs and crayfish. This food preference indirectly helps its "cousin" species, as crabs and crayfish eat fish eggs and this naturally affects the fish population. In fact, by eating large amounts of crabs and crayfish the white ibis has a uniquely positive effect on the fish population.

As with many similar species, the white ibis lives in colonies. As evening approaches, large groups of ibis band together and roost in trees adjacent to salt marshes and mudflats. They also nest in mixed large colonies, often mixed with other varieties of wading birds, such as herons.

The white ibis nest is located in trees that often overhang their feeding areas, and constructed with sticks. These large stick structures become home to three or four eggs that are greenish-white in color and decorated with dark uneven spots or markings.

Locating a white ibis to photograph or observe, within its predominant range, is not very difficult. What can be difficult is getting close enough to get a frame-filling image and setting a proper exposure for this bright white bird.

In many of the large marshes, the shallow water allows the bird to wade out a considerable distance from the shore. To photograph the ibis, as with most bird photography, requires a long telephoto lens mounted on a tripod. Setting up along the edge of the water, with the tripod legs at the lowest position, seems to work the best. Sitting down and keeping a low profile allows the bird to get comfortable with your presence and, very often, the bird will eventually work its way in your direction.

As mentioned, obtaining proper exposure can be tricky. This is a prime example of a situation where shooting on any of the "automatic" camera settings will produce an undesirable result. This occurs for two reasons; first, the bird is bright white, and secondly, the water is highly reflective.

What happens when photographing white subjects, with "automatic" exposure settings, is generally an underexposed image. All in-camera light meters are calibrated at what is referred to as "eighteen percent gray," or simply stated, calibrated for mid-tone subjects. Therefore, the camera meter attempts to make the white bird a mid-tone and doesn't allow enough light to reach the film. In other words, it underexposes the subject.

The reflecting light off the water surface further complicates the exposure, as the in-camera light meter "thinks" there is more light in the scene then what actually exists.

The way to solve this situation is simple. Take your meter reading in the same light as the subject, but away from the water. Once you have the correct exposure for a mid-tone subject, close down or underexpose slightly to bring out the white feather detail. Naturally, when you compose the shot of the bird in the water, the camera meter will read an incorrect exposure. Simply ignore the camera reading and shoot-away.

A tip for making the white ibis really stand out in your image is to find a spot where the water is shaded by an overhanging tree. Not only will the white bird stand out, but in calm water, a nice reflection of the bird is also possible.

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