Hook-billed Kite Life History

Habitat

Habitat ForestsAcross their large range in the Americas, Hook-billed Kites occur mainly along wooded streams and in lowland rainforest. They are nomadic, moving into areas to feed on booming snail populations, and then moving on when drought or other factors cause snails to become scarce. In their very small range in southern Texas, they are restricted to a 100-mile stretch along the Rio Grande where habitat is still intact and snails often abundant. Tree species here include Montezuma bald cypress, Sabal palm, Texas wild olive, live oak, tenaza, guajillo, tepeguaje, Rio Grande ash, Mexican leadtree, southern hackberry, black willow, retama, anacua, Texas ebony, granjeno, cedar elm, Wright’s catclaw, and honey mesquite. The kites often stay close to the river, but sometimes perch in drier mesquite habitats. From Mexico to the Caribbean and south to Argentina, Hook-billed Kites occur in lowland rainforest, especially edges near water or clearings, but also in dry coastal forest, thorn forest, and up into the lower temperate zone of the Andes, even over 10,000 feet elevation in Bolivia and Colombia. Back to top

Food

Food Aquatic invertebrates

Hook-billed Kites eat mostly tree snails, along with smaller amounts of insects, aquatic snails, crabs, frogs, and salamanders. To locate snails, the kites jump from limb to limb inside a tree canopy. They take the snail with the bill, then pass it to the left foot, holding it tightly to the perch, usually a tree limb. They then insert the hooked tip of the bill (on the upper mandible) into the shell, cracking it open. In this manner, a kite can consume many snails in a short period of time. They swallow very small snails whole. They often have favored perches for cracking, leaving behind telltale piles of shells under the tree. Some kites search for snails from the air, passing low over the treetops. Others are acrobatic hunters, even briefly hanging upside down to capture a snail in an awkward spot. Hook-billed Kites sometimes eat apple snails (genus Pomacea); and they also take terrestrial snails of several species. Snail prey include Yucatan snail, toothed dome, master tree snail, Caribbean tree snail, giant African snail (an exotic species found in Brazil), and other tree snails of many genera (Homolanyx, Polymita, Bulimulus, Strophocheilus).

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Nesting

Nest Placement

Nest TreeNests are set in trees, usually in the top half, ranging from about 15 to about 130 feet high.

Nest Description

Nests are messy platforms of sticks lined with smaller twigs, measuring about 11.8 inches across and 4.3 inches deep, a rather small nest for the size of the bird.

Nesting Facts

Clutch Size:1-2 eggs
Number of Broods:1 brood
Egg Length:1.8 in (4.5 cm)
Egg Width:1.5 in (3.7 cm)
Incubation Period:30-35 days
Nestling Period:24-38 days
Egg Description:Buff-white, with reddish-brown markings.
Condition at Hatching:Down-covered, unable to sit up.
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Behavior

Behavior Aerial Dive (ground/talons)Males and females court in the air, calling loudly and flying upward in tight circles as they swoop on one another, sometimes chasing each other just above the treetops. They build a sloppy-looking stick nest, usually not far from a river. In the tropics, nesting coincides with the rainy season, when snails are abundant. Both adults incubate the eggs and feed the young, though the female does more incubation, and the male often brings her food at the nest. The adults care for the young for several months after fledging. Back to top

Conservation

Conservation Low Concern

Very few Hook-billed Kites nest in the United States, but the species is numerous in Mexico, Central America, and South America. Partners in Flight estimates a global breeding population of 200,000 individuals and rates the species 12 out of 20 on the Continental Concern Score, indicating a species of relatively low conservation concern. Populations have declined substantially in much of the range due to habitat destruction and the introduction of non-native tree snails (which are too large for the kites to eat, and prey on smaller tree snail species). The subspecies on Grenada (mirus) is endangered, with fewer than 70 birds remaining, a result of habitat destruction and hurricane strikes. The subspecies on Cuba (Cuban Kite), sometimes considered a full species, is critically endangered.

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Credits

Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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