Family Eurylaimidae
broadbills

Broadbills are placed in the order Passeriformes, suborder Eurylaimi and family Eurylaimidae. There are four subfamilies of broadbills: Smithornithinae (typical African broadbills), Calyptomeninae (Asian green broadbills), Eurylaiminae (assorted Asian broadbills) and Pseudocalyptomeninae (Grauer’s broadbill). There are 9 genera and 14 species of broadbills. They are thought to be closely related to pittas (Pittidae) and asities (Philepittidae).

Broadbills are small to medium sized birds with a big head, a wide bill and often bright coloration (greens, reds, blues, etc.). They are primarily forest birds and live in rainforests of tropical Asia and Africa. Little is known about the mating behavior of this group. Some species are thought to be monogamous, others polygynous and some may be cooperative breeders. During displays, many broadbills make a loud trilling sound with their wings that can be heard up to 60 m away. Most species are gregarious. Some species eat primarily insects while others mainly eat fruit. (Bruce, 2003; Dickinson, 2003)

Broadtails live in the Ethiopian and Oriental regions. They are found mainly in tropical southeast Asia (from the Himalayas, southern China and the Philippines to Indonesia) and Africa. (Bruce, 2003; Campbell and Lack, 1985; Sibley and Ahlquist, 1990)

Broadbills are primary and secondary tropical forest species. Many species are found in the forest interior, but some are found in more open areas such as scrub, coastal bush, tree plantations and cultivated areas. They are often found near rivers and streams and live from sea level to 2550 m. (Bruce, 2003; Campbell and Lack, 1985; Wells, 1985)

Currently, broadbills are placed in the order Passeriformes, suborder Eurylaimi and family Eurylaimidae. There are four subfamilies of broadbills: Smithornithinae (typical African broadbills), Calyptomeninae (Asian green broadbills), Eurylaiminae (assorted Asian broadbills) and Pseudocalyptomeninae (Grauer’s broadbill). Classification of species within Eurylaimidae is still uncertain. Broadbills are thought to be closely related to pittas (Pittidae) and asities (Philepittidae). Asities used to be grouped in the family Eurylaimidae, but are now placed in their own family.

The most distinctive traits of broadbills are their foot tendons (the flexor hallueis and the flexor profundus tendons are joined by a vinculum band). They also have 15 cervical vertebrae, their podetheca has anterior scutes and posterior six-sided scales and their third and fourth toes are connected at the base.

In the past, broadbills were thought to be related to rollers (Coraciidae), trogons (Trogoniformes), nightjars (Caprimulgiformes), manakins (Pipridae), cotingas (Cotingidae) and flycatchers (Muscicapidae). Members of the genus Smithornis superficially resemble flycatchers, but are not closely related. (Bruce, 2003; Gill, 1995; Lambert and Woodcock, 1996; Payne, 2003; Sibley and Ahlquist, 1990; Wells, 1985)

Broadbills are small to medium sized birds; they are 11.5 to 28.5 cm long and weigh 43 to 117 g. They have a large head, a wide, flat, hooked bill, large eyes and a large gape. The structure of the bill depends largely on the species’ diet. Many broadbills have bright coloration (greens, blues, reds and yellows) which actually helps them blend in with the surrounding habitat. Members of Smithornithinae resemble flycatchers and have brown streaky coloration. Members of Calyptomeninae have primarily green plumage with black markings; males have iridescence. They also have loral plumes that extend over their bill making the bill appear smaller. Members of Pseudocalyptomeninae look similar to those in Calyptomeninae but have a longer tail and no loral plumes. The members of Eurylaiminae are variable in their plumage; the wattled broadbills have an eye ring of large blue wattles. Males and females are similar in some species and dimorphic in others. Sometimes males and females have different coloration, but the difference is usually subtle. Where sexual dimorphism exists, females are duller than males. Juveniles look similar to adults but are duller and have shorter wings and tails. (Bruce, 2003; Campbell and Lack, 1985; Wells, 1985)

Based on banding recaptures, broadbills are estimated to live at least 6 years in the wild. The oldest recorded bird in captivity was 19 years old. (Bruce, 2003)

Broadbills tend to be resident species. However, they commonly make altitudinal movements as seasons change and in dry seasons they may move beyond their normal range in search of food. A few species are nomadic and move around in search of fruiting trees; generally fruit-eating species are more nomadic than insectivores. Broadbills tend to show crepuscular activity patterns.

Although they are frequently found in pairs, broadbills also tend to be quite gregarious and are often found in small feeding flocks. Groups are not normally larger than 25 individuals. Broadbills seem to be territorial during the breeding season and their display flights may serve as both breeding and territorial displays. They may also defend small patches of fruit.

Broadbills often bathe in puddles and streams. (Bruce, 2003; Campbell and Lack, 1985; Lambert and Woodcock, 1996; Wells, 1985)

Broadbills are not known for having melodic or complex songs. They have a variety of calls usually described as whistles, rattles, trills, squeaks or screams. They call most often during the early morning and late afternoon. Calls are used in courtship, as alarm signals and for contact between mates. Broadbills often call more frequently when in groups. Members of the genus Smithornis have stiff outer primary feathers that make a buzzing sound (or wing trill) during display flights. The buzz is often louder than their calls and can be heard from 60 meters away. The wing buzz is used in courtship and territorial defense.

Broadbills also communicate using a variety of mating and territorial displays. Green broadbills (Calyptomena viridis) have a particularly notable spinning display. (Bruce, 2003; Campbell and Lack, 1985; Wells, 1985)

Most broadbills are insectivores. They catch insects while flying, glean them from vegetation or dart out from perches in a manner similar to flycatchers (family Muscicapidae). They are opportunistic feeders, and commonly eat Orthoptera (grasshoppers and relatives), Coleoptera (beetles), Hemiptera (true bugs and relatives), Hymenoptera (wasps, bees and ants) and Isoptera (termites). Less frequently they will also eat Diplopoda (millipedes), Araneae (spiders), snails (Gastropoda), crabs (Decapoda), tree frogs (Anura), lizards (Sauria) and fish (Actinopterygii). Three broadbill species are frugivores and their bill structure reflects the dietary differences. The frugivorous species lack the wide bill of the insectivores, but maintain the wide gape. Because of this modification they are not able to easily manipulate the fruit with their bills and so they are forced to eat relatively soft fruits and/or to swallow the fruit whole. Figs are an important food source for fruit-eating broadbills. Frugivores will often catch insects to feed their young during the breeding season. (Bruce, 2003; Campbell and Lack, 1985; Lambert and Woodcock, 1996; Wells, 1985)

Nests are built hanging from small branches and extend over open areas, often over water. This is thought to be an adaptation to deter mammalian and reptilian predators. Sometimes nests are also built in thorny trees or near wasps and bees that presumably provide some protection to the birds. Adults will feign injury to draw predators away from their nest. (Bruce, 2003)

Broadbills play an important part in controlling invertebrate populations throughout their range. They also aid in seed dispersal. Broadbills are also hosts to parasitic cuckoos (family Cuculidae). (Bruce, 2003)

There are no known adverse affects of broadbills on humans.

Broadbills disperse seeds of plants that are eaten by humans. Broadbills themselves are also eaten by humans. Because of their colorful appearance, they are sometimes sold in the pet trade and are sought out in the wild by tourists. They also play an important part in controlling invertebrate populations throughout their range. (Bruce, 2003)

Broadbills live in lowland rainforest that is rapidly disappearing. The loss of habitat due to increases in agriculture combined with their poor ability to adapt to disturbance leaves broadbills in a vulnerable position. The IUCN lists three species of broadbill as vulnerable (visayan broadbill (Eurylaimus samarensis), wattled broadbill (Sarcophanops steerii) and Grauer’s broadbill (Pseudocalyptomena graueri)) and three as near threatened (Hose’s broadbill (Calyptomena hosii), green broadbill (Calyptomena viridis) and black-and-yellow broadbill (Eurylaimus ochromalus)). (Campbell and Lack, 1985; IUCN, 2002; Lambert and Woodcock, 1996)