Smooth-billed Ani Life History

Habitat

Smooth-billed Anis live year-round in savannas, pastures, second-growth scrub, overgrown fields, and most other lowland tropical habitats except mangroves and rainforest. In many places they thrive in disturbed and human-altered areas such as parks, nurseries, orchards, sugarcane fields, even suburbs. Unlike its nearest relative, the Groove-billed Ani, the Smooth-billed is most common near freshwater such as ponds, rivers, or marshes, and they typically roost near water, often in stands of reeds or cane. In some locations, Smooth-billed Anis thrive in more arid environments such as thorn scrub. Increasingly, Smooth-billed Anis have colonized deforested areas high in the mountains, up to 8,200 feet elevation in Colombia.

Food

Smooth-billed Anis eat mostly insects and small lizards. They also eat berries and fruits, particularly during the dry season. They capture insects in quick pounces, sometimes in short flights. They also hop along awkwardly through bushes and small trees, trying to spot or flush insects or small lizards and sometimes plucking fruit. Occasionally, they sally into the air after a large flying insect. Smooth-billed Anis are drawn to herds of cattle, which flush up prey items as they move through pastures. They also visit swarms of army ants, which likewise flush hidden prey items. Prey items include grasshoppers, katydids, cicadas, butterflies and moths (and caterpillars), bees, ants, wasps, junebugs and other beetles, flies, dragonflies, cockroaches, ticks, tree snails, tree frogs, and small lizards (anoles). Smooth-billed Anis consume fruits of gumbo-limbo, royal palm, fiddlewood, and possum grape, usually removing the skin and regurgitating the seed.

Nesting

Nest Placement

A paired male and female usually select a nest site, which results in multiple potential nest sites and nests for the group. The group eventually settles on one nest, set in a tree or bush, often a thorny one but also in palms, bamboo, or vine tangles. Nests can be 2–50 feet off the ground.

Nest Description

All group members construct a bulky cup of twigs that they line with green leaves. Nests vary in dimensions but average about 11.8 inches across and 5.9 inches tall, with interior cup 6.3 inches across and 2.8 inches deep.

Nesting Facts

Behavior

Smooth-billed Anis are highly social birds that live in groups of up to five pairs plus offspring. Group members feed, roost, and travel together. When the group is foraging, one or two members will sometimes perch in a tree or snag as sentinels, watching for predators. When not foraging, Smooth-billed Anis often sit close together, preening one another. Most members of the group defend the group’s territory (about 15–24 acres), and unfamiliar Smooth-billed Anis that do not move on quickly may be attacked. Within groups, pairs behave as if monogamous, but some males mate with multiple females in the group. In breeding season, males defend their mates against approaches by other males, but conflict is usually minimal. Courting males present a large insect or a lizard to the female. Females that accept the offering usually consent to mating by drooping their wings forward; the male flaps his wings dramatically when mating. All females within the group lay eggs in a communal nest, though only the eggs in the top layer of the nest actually hatch. All members of the group share nest-building, incubation, and chick-feeding duties. When a male comes to relieve his incubating mate, he sometimes presents her with a leaf or twig, a continuation of a behavior that starts with nest-building. Once the young have fledged, they remain with the group for a year or more. In some regions, Smooth-billed Anis become less territorial after breeding and wander widely, especially during the dry season, sometimes gathering in wetter areas and forming sizable flocks of 50–60 birds. In some parts of the range, they remain in territories and breed year-round.

Conservation

Smooth-billed Anis are common through much of their range, but their population trends are unknown. Partners in Flight estimates a global breeding population of 20 million and rates the species an 8 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Despite being common in South America, Smooth-billed Anis in Florida have been declining since the 1970s, mostly due to massive landscape changes. Other possible factors include increasing use of pesticides, and mortality during the cold winters of 1976–1978.

Credits

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Quinn, James S. and Jennifer M. Startek-Foote. (2000). Smooth-billed Ani (Crotophaga ani), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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

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