Coua crestata

Identificazione

The adult crested coua is a medium-sized bird, averaging between 12 and 17 inches (30 to 44 cm) in length. It has a greenish-gray plumage on the back, a white abdomen, rufous-colored chest and brown eyes. Its long tail is purplish-blue with white tips and its bill and beak are black. Its defining characteristics are its prominent grey head crest and, as goes for all couas, its colourful patches of bare skin around the eyes, which is blue and turquoise in crested couas. In flight, it is recognizable from its short rounded wings and long white-tipped tail.<p>Furthermore, this bird's third toe is reversible, which helps it have a strong grip when hopping around high branches in the canopy. Although they are common birds in their range, they can be hard to see in the wild since their greenish-gray coloration tends to blend with shadows and acting as camouflage. Males and females are similar physically.<p>Juveniles are comparable to adult crested couas however, they are paler in colour, have a shorter head crest and do not have the characteristic bright blue and turquoise ring around the eye.<p>Young chicks are altricial, which means they are naked at birth and need full parental attention for their early development. During that time, they have unique red and white "bullseyes" inside their mouth, supposedly used to indicate to their parents where to put the food. This characteristic is thought to be particularly useful at darker hours of the day. They also have a dark skin and a reddish bill at that stage.

Tassonomia

The crested coua is one of nine living bird species in the subfamily Couinae, which only has one genus, the Coua. These birds are part of the order Cuculiformes, which includes Cuckoos, Turacos and Roadrunners. Couas are a monophyletic group of endemic birds of Madagascar.<p>Three of the coua species are arboreal (Blue Coua (C. caerulea), Crested Coua (C. cristata) and Verreaux's Coua (C. verreauxi)), and six species are ground dwelling (Coquerel's Coua (C. coquereli), Running Coua (C. cursor), Giant Coua (C. gigas), Red-fronted Coua (C. reynaudii), Red-capped Coua (C. ruficeps) and Red-breasted Coua (C. serriana)).<p>The crested coua has four subspecies:

Nome scientifico

Coua cristata

Autorità

(Linnaeus, 1766)

Ordine

Cuculiformi

Famiglia

Cuculidae

Genere

Coua

Areale e habitat

Crested couas are endemic to Madagascar and are the most widespread of all couas. Although their population numbers are unknown, their range is thought to be 562,000 sq km along the coast of the island. They are found at altitudes as high as 900m above sea level, but are most commonly seen around altitudes of 700m.<p>Despite being mostly found in littoral and deciduous forests, their habitats also consist open areas like savannas and brushlands. They will occasionally be found in mangroves and palms as well. Additionally, they usually avoid deciduous shrublands, selecting mainly for mosaics of forests and croplands. As arboreal species, they tend to use forest layers above five meters and they nest, on average, around nine meters from the ground.

Migrazione

Resident species

Comportamento

Despite being capable of flight, crested couas are weak flyers, so they are rather observed restlessly bouncing between branches in the canopy. Keeping balance with their long tail and grasping branches with their reversible toe, they are able to move quickly and be agile. Secretive, they tend to stay in groups of three to five individuals outside of breeding season. They do not tend to flock, although they sometimes join mixed-species flocks.<p>They are highly vocal birds and have several different calls that we can hear in the wild. The most commons are “laser gun calls”, which are a series of piercing sounds, and doubled, wooden “touk-touk” sounds. It is also possible to hear calls such as “koa-koa-koa” and “guay-guay-guay-guay-gwuck”. Its call can sometimes serve as an indicator of predator presence in the environment.<p>Couas, like many birds, tend to be more vocal around sunset, often creating mixed chorus with other species. They also raise their head crest while calling.<p>Breeding crested couas are usually found in monogamous pairs. Unlike some other species of cuckoos, these birds do not take part in brood parasitism, but rather, both male and female co-parent the chicks. The pair builds their nest themselves out of twigs and hide it in trees or bushes to avoid detection by predators. Two single white eggs are laid and incubated by both parents. The chicks are born altricial with both parents equally helping in raising the young until they are about two weeks old, when they leave the nest. Couas have low fecundity, but they have a high adult longevity (up to 15 years in captivity), which is why they can afford to have a smaller brood size. Additionally, because of their short young-rearing period, it is possible for them to have several clutches in one breeding season, which is from September to March.<p>They have an omnivorous diet consisting of arthropods, fruits, berries, snails, chameleons, leaves, seeds and others. They essentially feed on everything size appropriate that they find in their environment.

Conservazione

Tendenza della popolazione

declining