Cuckoo-roller

The cuckoo-roller, also called the courol (Leptosomus discolor), is the sole member of the bird family Leptosomidae. It was once classified under the order Coraciiformes, but is now placed in its own order, Leptosomiformes. Evolutionarily, it sits at the base of a group that includes trogons, hornbills, woodpeckers and allies, and rollers. Despite its common name, it is not closely related to either cuckoos or true rollers, though it was long considered a near relative of the latter.

This medium-large bird lives in forests and woodlands of Madagascar and the Comoro Islands. Three subspecies are recognized: the nominate *L. d. discolor* on Madagascar and Mayotte Island; *L. d. intermedius* on Anjouan; and *L. d. gracilis* on Grande Comore. Because *gracilis* is smaller, has different plumage, and a slightly different call, it is sometimes treated as a separate species, the Comoros cuckoo-roller (*L. gracilis*).

The cuckoo-roller measures 40–50 cm (16–20 in) in total length, with the nominate subspecies being the largest and *gracilis* the smallest. Unlike true rollers and ground rollers, where males and females look alike, this species is sexually dichromatic. Males have a velvety grey head and chest that gradually fades to white on the lower underparts (the grey-white border is sharper in *gracilis*). Their back, tail, and wing coverts are dark iridescent green with a purplish sheen, especially on the wing coverts, and the crown and eye-stripe are black. Females are mostly brown, with pale underparts heavily marked with dark spots (less spotting in *gracilis*). Juveniles generally resemble dull females, but at least in *gracilis* the young are sexually dimorphic, and this may hold for the other subspecies as well. The bill is stout, the eyes are set far back on the face, and the legs and feet are small. The foot structure is unusual and long puzzled ornithologists; it is now considered zygodactylous, with two toes pointing forward and two backward.

The cuckoo-roller occupies a wide range of habitats, including altered areas. It lives in rainforest, littoral forest, deciduous forest, spiny bush-forest, and tree plantations. In the Comoros, it occurs on all major islands, especially in forested zones, and can be found from near sea level up to 2,000 m.

Its diet is not well known, but a 1931 expedition found that chameleons and insects—especially locusts and caterpillars—are important. Stomachs have often been lined with caterpillar hairs. Other prey includes grasshoppers, cicadas, stick insects, and geckos. The bird typically forages by perching motionless and watching for prey, then making a quick dash to catch it. It also hunts from the air. Prey is seized in the large bill and killed by beating it against a branch.

Very few studies have looked at its breeding habits. It was once described as a polygamous breeder, but there is no evidence for this. The nest is placed in natural cavities in tall trees, 4–6 m (13–20 ft) above ground, with no lining; the white eggs are laid directly on the cavity floor. The usual clutch size is about four eggs. Only the female incubates, while the male feeds her. The incubation period is roughly 20 days, after which fluffy chicks hatch. The young remain in the nest for 30 days before fledging.

The species is not generally hunted and has proven resilient to habitat changes that threaten other native birds. It is assessed as Least Concern by the IUCN, though its total population size has not been estimated. Its distribution is vast, and populations in Madagascar persist even in small forest fragments. Abundant populations are found in large forest reserves such as Zahamena, Andringitra, Andohahela, and Marojejy.

The cuckoo-roller is very tame and is generally not disturbed by Madagascar’s inhabitants, many of whom have legends and myths about it. It is often seen as a good omen, a harbinger of clear weather, and—because it is frequently seen in pairs—associated with couples and love.