Beak of the Week – White Ibis

The White Ibis is an easy to recognize resident on the upper Texas coast. They are often found in groups in wetlands and estuaries across the southeastern United States. White Ibises occur year round in our area and will breed in our area, but they are most common spring through fall. Standing at about two feet tall, the White Ibis has long legs and a curved bill. Adults have white bodies with black wingtips and a bright red face, bill, and legs. Juveniles are mottled white and brown and have a duller face, bill, and legs. Both adults and juveniles have bright blue eyes. Their call is a nasal honk given in flight or while foraging.

White Ibises will thrive in many types of salt, brackish, and freshwater wetlands including swamps, estuaries, marshes, and mangroves. They will also forage on wet lawns, fields, and in parks. During the breeding season, White Ibis are unique in that they require two types of habitats: brackish marshes to find food for themselves and freshwater marshes to find food for their young, which are unable to digest salts found in saltwater organisms. White Ibises forage for insects and crustaceans, such as crayfish, earthworms, marine worms, and crabs. They sweep their bills side to side and probe for prey. They will also eat frogs, lizards, snails, and newts.

White Ibises are social birds; they forage in groups, fly in groups, and nest in colonies. Males will gather in large groups at the colony before breeding to attract a female. They perform several displays that involve head shaking, preening, bathing, group flights, and bill popping. Males and females typically form monogamous pairs, but males often mate with more than one female. Males will defend their female and nest from rival males during breeding season.

Within the colony, female White Ibises choose a nesting site. The male will then gather sticks for the nest and give them to the female, where she will then construct the nest in the fork of a dead tree. It takes about a week to build a nest, which is continuously maintained throughout the nesting season. Both the male and female will incubate the eggs and care of the nestlings. When baby Ibises hatch, however, their bills are straight and do not start to curve until they are about 14 days old. The parents will feed the nestlings until they can forage by themselves. Flying in a flock also takes some practice, as juveniles don’t fully learn the technique until they are about two months old.

The White Ibis is a permanent resident to the upper Texas coast, across the southeastern United States and all of Florida. They are also permanent residents to the coasts of Central America, northern South America, and throughout the Caribbean. Some are medium-distance migrants, and will migrate to the Southeastern United States coasts from inland areas. Some populations primarily winter in parts of Central America and Baja California. They can be found in the Smith Oaks, Horseshoe Marsh, and Dos Vacas Muertas Houston Audubon sanctuaries. Other good places to observe these birds include: Anahuac National Wildlife Refuge, Brazos Bend State Park, Galveston Island State Park, or at any of the marshes along the coast.