Collared forest falcon

Appearance

The collared forest falcon has a dark coloured back with a white neck and breast. The species has three morphological variants : pale, tawny and dark. The former two have a light coloured collar at the back of their neck, which explains their name. This is the largest species of the forest falcon genus, with a total length of 46 to 58 cm, wingspan of 72 to 86 cm and male weights of 467 to 646 g, averaging some 523 g, and female weights of 649–940 g, averaging 740 g, this species is nearly the size of peregrine falcon albeit longer-tailed and much shorter-winged. Although its forest lifestyle, rounded short wings, long tail and lack of the characteristic beak tooth suggest affinities to hawks, there are several morphological connections to the Falconidae in which it is now placed, e.g. moult pattern and the morphology of the skull.

"M. semitorquatus" display sexual size dimorphism, with the female being much larger than the males on many accounts such as mass, size of beak, tail and wing chord. It averages a value of 9.5 on the dimorphism index. This value was calculated from observations done at Tikal National Park in Guatemala.

Nestlings are born with a cover of natal down, white nails, light yellow legs and short, deep, laterally, yellowish white compressed beaks. Their heads are held up and eyes open after a couple days. Pupils begin with a blue back hue and black iris which turns to a more chocolate brown after four weeks. After a few weeks the young are able to defend themselves if bothered. Down feathers will be gone by the sixth week, replaced with juvenile feathers. However, fledging will occur before wing and tail feathers are completely grown. In the weeks that follow, fledglings will continue to move further from the nesting site as they grow bigger and more confident.

Distribution

The species is commonly found in many Central and South American countries: Argentina, Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname and Venezuela. The species is extremely widespread, with a total estimated population between 500,000 and 5 million individuals. Furthermore, they are year-round residents of their Latin American home.

Behavior

Hiding in the dense forest canopy, they are a secretive bird often only recognized by their distinctive call. With a morphology or body type allowing them to be agile in their forested habitat, their diet comprises a wide variety of prey from smaller frogs to adult turkeys.

Nesting occurs mainly in the cavities of Spanish cedar trees, which are also a key species exploited by the local logging industry. This is a potential conservation concern for the collared forest falcon.

Habitat

Due to their distinct morphology, the collared forest falcon is able to inhabit a variety of habitats from moister regions such as mangroves, tropical and rain forests to gallery forest and tall second growth. They tend to prefer regions where the undergrowth is relatively dense and where they can move and hunt more easily within it. They range from sea level to 2500 m elevation.

Around ten territorial pairs are estimated to occupy a 100 km2 area. However, these estimates are based on radio telemetry of individuals during the breeding season and therefore they may be different in another context.

Reproduction

Courtship activities including vocalizations, searching and guarding of nest sites, prey exchanges and copulation occur during the dry season from January to March. Egg laying spans a 30-day period, peaking during the month of march. Next, the incubation period lasts about 46–48 days with the female as the one doing the task. The male meanwhile provides all the food for this period. On average the young fledge at 50 days old. Moreover, they stay dependent on their parents for an additional 6–11 weeks. It is late into the nestling period before the mother is able to leave the nest to go hunt and the father is no longer the sole provider of food for the family. In addition, there have been some accounts of a collared forest falcon feeding fledglings that are not his own. Little is known on why this would occur and/or how often this type of behavior is exhibited.Collared forest falcons use the cavities of large trees and wood debris as their nests. All are non-excavated nesting sites, occurring naturally through decay or broken limbs. Nothing extra is brought into the nest as bedding or support. The entrances and nests themselves are quite large to accommodate for the size of the female birds. Furthermore, larger trees are favored for that same reason. In this regard, Spanish cedar seemed to be selected more often, in other words there was a positive selection for this species. Other species of trees observed to be used as nesting sites includes: Honduras mahogany, Black Cabbage-bark, Yellow Mombin and Chicozapote. Nesting in live trees proved highly more successful than in dead trees, which were mostly unsuccessful. Most breeding pairs will use the same nest site in subsequent years.

Food

The collared forest falcon will catch its prey by first concealing itself in the dense forest canopy before pursuing by flight, or running and hopping along the forest floor. This hunting of animals is thought to be aided by their specialized sense of hearing supported by a more pronounced facial disk, also seen in owls and harriers. Flexible tail feathers are also helpful when going after prey in dense forest areas. Differences were observed in the hunting techniques among individual "M. semitorquatus'."

The "Micrastur" species enjoys a wide variety of prey such as birds, mammals, lizards, snakes and insects. In a study conducted from 1990–92, prey items delivered to the females, nestlings and fledglings were counted and identified to species. 223 prey items were accounted for, 171 of which were identified. Results showed that the largest proportion of the collared forest falcon's diet consisted of mammals. Then, 34.5% were birds, 18.7% reptiles and 0.6% amphibians. Prey ranged from smaller 20 g to very large 2.7-3.2 kg.

Comparisons with the diet of its relative the barred forest falcon " showed that the collared forest falcon had a mean prey weight that was 10 times greater. Since the "M. semitorquatus" is three times larger than "M. ruficollis," a comparaison with another larger raptor could prove more interesting in terms of dietary overlap.