White-faced Ibis, Plegadis chihi

White-faced Ibis, Plegadis chihi. Bird photographed in the wild in the Los Cabos area of Baja California Sur, December 2019. Photograph courtesy of Dr. Tom Bartol, Carlsbad, California.

White-faced Ibis, Plegadis chihi. Photograph taken in rural Benito Juarez, Sonora, March 2020. Photograph and identification courtesy of David F Smith, Alamos, Sonora.

The White-faced Ibis, Plegadis chihi, is a member of the Threskiornithidae Family of Ibises and Spoonbills, which has thirty-six global members placed in thirteen genera and one of three global members of the Plegadis Genus. They are known in Mexico as ibis cara blanca.

The White-faced Ibis, Plegadis chihi, is medium sized in stature. They are sexually dimorphic with males being significantly larger than females. They are an overall dark chestnut-maroon with a metallic green and bronze sheen with their wings having purplish overtones. Their facial skin is reddish purple, their bill is an olive gray, their iris is reddish brown, and their legs and feet are black. When breeding they develop distinctive white feathers along the edge of their bare facial skin, for which they are named, their legs become a bright carmine. They are a long-legged wading bird that has a long neck and a long decurved bill.

The White-faced Ibis, Plegadis chihi, are found primarily with freshwater wetlands, flooded meadows, agricultural fields, and estuarine wetlands at elevations up to 4,300 m (14,100 feet). The majority are highly migratory summering and nesting in the marshes of the western United States, and they winter in large flocks in the southern United States and Mexico. Winter visitors have been found as far south as Michoacán, Puebla, and Campeche. Year-round breeding populations have been documented in in Durango, Jalisco, Tabasco, and Tamaulipas. They roost close together in communal groups in reeds or low scrubs over water. They leave roosting and nesting marshes early morning to feed in large flocks consisting of excess of 1,000 individuals on moist-soil insects, crustaceans, and earthworms. They also frequent alfalfa fields and feed less often in barley, corn, oat, and wheat fields. They are high gregarious nesting in large colonies with the nests being defended by both pair members. Their unguarded nests are vulnerable to predations but a series of gulls, grackles, herons, magpies, owls, ravens, coyotes, mink, racoon, skunks, and weasels. They are known to nest at different sites changing year to year depending on the local water conditions. They are harassed by gulls and grackles when feeding and by American Coots when they enter the Coots territories. They have life spans of up to fifteen years.

The White-faced Ibis is a straightforward identification and the only Ibis found in Mexico.

From a conservation perspective the White-faced Ibis is currently considered to be of Least Concern, with stable widely distributed populations. However, their populations are poorly documented. They date to the Pleistocene Period, up to 2.6 million years ago. They are currently hunted in Mexico on a limited basis for human consumption. Their population have been adversely affected by human development and disturbance of their breeding territories and by pesticides and heavy metals found in their water habitats. They are considered to be a Threatened or Endangered in some parts of their range. In some areas they are known pests damaging crops and consuming crayfish from crayfish farms.