Jacamars (Galbulidae)

(Galbulidae)

Class: Aves

Order: Piciformes

Suborder: Galbulae

Family: Galbulidae

Thumbnail description
Slim tree birds, similar to an oversized hummingbird, with iridescent green plumage and long pointed bills

Size
5–12 in (13–31 cm)

Number of genera, species
5 genera; 17 species

Habitat
Neotropical forests

Conservation status
Endangered: 1 species; Vulnerable: 1 species

Distribution
Central and South America, from Mexico to Argentina

Evolution and systematics

With their brilliant colors and energetic ways, jacamars resemble hummingbirds but are actually related to puffbirds, toucans, and woodpeckers. Like all members of the order Piciformes, jacamars and their relatives have zygodactyl feet, with two toes pointing forward and two facing back. Jacamars evolved with this toe arrangement, which helps them grasp branches while hunting in trees. Jacamars, like woodpeckers and other piciform birds, are cavity nesters: they tunnel into the ground to build nests. Scientists believe jacamars are closely related to Old World bee-eaters, which also prey on flying insects, have similar plumage, and raise their young in the same manner.

Jacamars tend to live near lush tropical rainforests, which have a dazzling variety of large, colorful butterfly species. Jacamars have become highly selective predators. They often make their homes near streams, drilling nest cavities into steep banks and upturned tree roots.

Because 13 of the 17 Galbulidae species belong to super-species complexes, researcher J. Haffer concludes that jacamars had a relatively recent Pleistocene radiation of the family. Jacamars are believed to have originated in the Amazon region where they are most common, and spread to other parts of Central and South America. Unique anatomical features of this family include a long appendix, no gall bladder, a bare preen gland, and a long, thin tongue.

Physical characteristics

Wildlife enthusiasts treasure jacamars for their jewel-like colors. Their most distinctive characteristic is the long, sharp bill they use to snatch prey out of the air. In some species, the bill can be three times as long as the bird's head. Jacamars vary in size, from the brown jacamar (Brachygalba lugubris), at 7 in (18 cm) long, to the 1-ft-long (30 cm) great jacamar (Jacamerops aurea).

All jacamars, except one species, have short legs with four toes: two facing forward and two facing back. The three-toed jacamar (Jacamaralcyon tridaetyla), however, lacks the rear (first) toe. A jacamar has a long tail, with 10–12 graduated tail feathers. The short wings have 10 primaries, and contour feathers have a short secondary shaft (except in the genus Malacoptila).

Males and females have similar plumage, although females of some species may have less striking colors on the head and neck. Jacamars, known for their brilliant plumage, typically have a metallic green head, reddish underparts, and a light patch on the throat or breast. Some species have color variations ranging from purple to red or chestnut brown. The paradise jacamar (Galbula dea) has much darker bluish black plumage with a contrasting white patch on the throat and a long, elegant tail.

While most newly hatched piciform birds are born naked, jacamars are covered with white down. By the time they leave the nest, plumage resembles that of the parents.

Jacamars are not songbirds, but A. Skutch has noted that they have loud calls, trills, and short songs that could be considered melodious.

Distribution

Jacamars occur mainly at low altitudes, ranging from southern Mexico to northern Argentina. The most widespread species, the rufous-tailed jacamar (Galbula ruficauda), occurs in Costa Rica, Trinidad, Mexico, Ecuador, Colombia, Brazil, and Argentina. The distinctive great jacamar ranges from Costa Rica to the Amazon basin. The green-tailed jacamar (Galbula galbula) is found north and south of the Amazon. More rare is the coppery-chested jacamar (Galbula pastazae), which has a low population. It has been observed at a small number of sites in southern Colombia and along the slopes of the Ecuadorian Andes.

Habitat

Jacamar habitat includes Neotropical rainforests, streams or riverine forest, and savanna woodland. Generally, jacamars live at the edge of forests. Jacamars prefer habitat that supports their favorite prey—large, showy butterflies. Suitable nesting sites, such as dirt masses associated with fallen trees and sandy or clay stream banks, also are key. The rufous-tailed jacamar prefers low-lying thickets that border rivers, while the paradise jacamar seeks a higher perch. The coppery-chested jacamar lives at the highest elevations of all jacamars. It has been observed at altitudes of 5,100 ft (1,550 m) in the Andes. It is a resident of the eastern slope of the Ecuadorian Andes, although its distribution is patchy, and its population is dwindling due to habitat loss.

Behavior

Jacamars are exciting to watch because they are dramatic acrobats, swooping down from perches to capture colorful prey in mid-air. They spend most of their time on a branch, alert and scanning the air for flying insects.

Typically, jacamars live in pairs that perch and hunt in the same area. Certain species will occasionally congregate in small family groups. Unlike other jacamar species, the yellow-billed jacamar (Galbula albirostris) often joins mixed flocks of birds. Jacamars use a variety of calls to communicate. For example, rufous-tailed jacamars signal danger or agitation with a sharp trill.

Feeding ecology and diet

As an entirely insectivorous family, jacamars prefer large, showy, flying insects. Their diet consists of butterflies, moths, wasps, dragonflies, and flying beetles. A long, forceps-like bill allows the jacamar to grasp its prey while keeping it at enough of a distance to avoid becoming blinded by fluttering wings or injured by a stinging insect. Once they catch an insect, jacamars batter it against a tree branch to kill it, and remove the wings before swallowing.

Favorite food sources include beautiful blue morpho butterflies, hawk moths, and venomous Hymenoptera such as bees and wasps. Skutch also observed a preference for butterflies and dragonflies. In his work, Chai described how young rufous-tailed jacamars in Costa Rica learned to discriminate between butterfly species by color, markings, and flight patterns. Jacamars tend to reject butterflies with chemical defenses that make them less palatable. With their specialized hunting skills, jacamars may have played a major role in the evolution of butterflies that live in jacamar habitats.

Reproductive biology

During breeding season, male jacamars engage in lively vocal performances, with a series of explosive, sharp calls. Two rival males use this display of courtship and verbal bravado to impress a potential mate. Jacamars form monogamous pairs.

Jacamars dig holes for nests in steep river banks. They use the bill to break up the soil, then remove it by kicking backwards with their feet as they burrow. These tunnels also can be found some distance from the water, on soil banks or roots of fallen trees. The nest sits at the end of the tunnel in a horizontal, oval-shaped terminal chamber. Some jacamars, including the rufous-tailed jacamar, may use termite nests for breeding if no appropriate site to dig a ground tunnel can be found. Tunnels are 12–36 in (30–91 cm) long and about 2 in (5 cm) in diameter. The nest chamber is used repeatedly and does not contain nest material, although eggs often are covered with a layer of regurgitated insect parts. In some species, male and female participate in building the nest hole; in other species only the female does this work.

Jacamars lay one to four round, glossy, white eggs. Both parents incubate the eggs during the day for one to three hours at a time. At night, the female incubates alone while the male stays nearby to defend the nest. Jacamars rarely leave eggs unattended. During incubation, the male feeds his partner several times each day. The incubation period is 20–23 days.

Both parents feed the young with insects. Chicks remain in the nest 21–26 days. Unlike other species, young pale-headed jacamars (Brachygalba goeringi) may return to the burrow to sleep with the parents for several months after they fledge.

Conservation status

Habitat loss is a continuing threat to jacamars. In Brazil, intensive clearance of understory vegetation in forest fragments caused a decline of jacamar populations, along with an overall lack of bird species diversity in the area.

Only one jacamar species, the three-toed jacamar, is classified as Endangered. This species prefers lowland tropical rainforest, plantations, tropical monsoon, and dry forest. The three-toed jacamar used to thrive in southeast Brazil, including eastern Minas Gerais, Espírito Santo, Rio de Janeiro, São Paulo, and Paraná. Development and agricultural land use have destroyed much of its habitat. The remaining population, restricted to Rio Paraíba valley in Rio de Janeiro and the dry regions of Minas Geraís, is small and fragmented. The three-toed jacamar is protected under national law in Brazil. The Caratinga Reserve in Brazil offers a safe haven for this endangered species.

The coppery-chested jacamar—found in montane tropical rainforests of Colombia, Ecuador, and Amazonian Brazil—is classified as Vulnerable. Its total population is believed to be small and declining due to destruction of its forest habitat.

Significance to humans

The Tupi, an indigenous population in Brazil, gave the jacamar its name. It is derived from a Tupi word, jacama-ciri. Over the years, people in the region have given this popular bird nicknames such as "bico-de-agulha" (needle bill) and "beija-flor grande" (big hummingbird).

Species accounts

Resources

Hilty, Steven L., and William L. Brown. A Guide to the Birds of Colombia. New Jersey: Princeton University Press, 1986.

Janzen, Daniel H., ed. Costa Rican Natural History. Chicago: University of Chicago Press, 1983.

Chai, P. "Butterfly Visual Characteristics and Ontogeny of Responses to Butterflies by a Specialized Tropical Bird." Biological Journal of the Linnean Society 59, no. 1 (1996): 37–67.

Chai, P. "Field Observations and Feeding Experiments on the Responses of Rufous-tailed Jacamars to Free-flying Butterflies in a Tropical Rainforest." Biological Journal of the Linnean Society 29, no. 3 (1986): 161–189.

Marsden, Stuart, J., Mark Whiffin, and Mauro Galetti. "Bird Diversity and Abundance in Forest Fragments and Eucalyptus Plantations Around an Atlantic Forest Reserve, Brazil." Biodiversity and Conservation 10, no. 5 (2001): 737–751.

Neotropical Bird Club. c/o The Lodge, Sandy, Bedfordshire SG19 2DL United Kingdom. E-mail: secretary @neotropicalbirdclub.org Web site:

Caratinga: Soundscapes from Brazil's Atlantic Rainforest. Compact disc, Earth Ear Catalog, 2001. Available online at

The IUCN Red List of Threatened Species. Species Information: Three-toed Jacamar.

[Article by: Melissa Knopper, MS]