FROGMOUTHS: Podargidae

PHYSICAL CHARACTERISTICS

Frogmouths received their name because their large beaks look like the mouths of frogs. Like others in the order Caprimulgiformes, frogmouths have large heads and large eyes. Members of this order are nocturnal, and their large eyes help the birds see at night. Their middle toe is longer than their other toes. Unlike other Caprimulgiformes, frogmouths do not have a toe on each foot that is serrated, separated into parts like the teeth of a comb.

Frogmouths have been said to resemble owls. While both owls and frogmouths are nocturnal, active at night, and have large eyes, there are some differences. Frogmouths have wide, curved bills. Owls have short, hooked bills. Frogmouths have short legs and small feet. Frogmouths do not have talons, the sharp claws that characterize birds of prey like owls.

Prey is the animal or plant that predators hunt for food. The bill and mouth help frogmouths capture food. Their wide-bill reveals a large gape, open mouth. Around the bill are bristles. These whisker-like hairs are believed to guide the prey into the bird's mouth.

Frogmouths have soft plumage, feathers, and weigh from 1.5 to 23.6 ounces (43 to 670 grams).

There are three species in the Australian frogmouth genus (JEE-nus; group of related animals within a family), Podargus. Feather colors include various shades of brown and gray. Patterns in the plumage such as white spots and black streaks help to camouflage birds. With this protective coloring, birds blend in with the trees where they perch. Birds range in length from 12.8 to 15.2 inches (32 to 38 centimeters). Their tails and wings are long.

The remaining ten species belong to the Asian frogmouth genus, Batrachostomus. Plumage is mostly brown on males of some species. Females are bright rufous, reddish brown. The Asian frogmouths are smaller than Australian frogmouths. The length of Asian frogmouths ranges from 9.2 to 16 inches (23 to 40 centimeters.) Most Asian species have wider bills and longer tails than their Australian relatives. Their wings are more rounded than Australian frogmouths.

GEOGRAPHIC RANGE

Australian frogmouths live in Australia, New Guinea and surrounding islands, Tasmania, and the Solomon Islands. Asian frogmouths live in Asian countries including India, Vietnam, Sri Lanka¸ the Philippines, Borneo, and Java.

HABITAT

Frogmouths live in a range of habitats where there are trees. Some species live in rainforests where heavy rain produces plenty of trees. Other birds live in grassland and scrub areas where there are fewer trees. Species live in plantations, where people plant trees, and birds also live in neighborhoods.

DIET

Frogmouths are insectivores, insect eaters. Their diet includes caterpillars, beetles, and millipedes, insects with many legs. Some species eat spiders, frogs, and mice. They fly to the ground to capture food or chase after flying prey like moths.

HIDING IN PLAIN SIGHT

Frogmouths rest in trees during the daytime, camouflaged by plumage that resembles the colors of the branches where they roost. The birds do not just rely on their coloring to keep them safe. Frogmouths sleep lengthwise, as if standing up. If they sense a disturbance, birds shut their eyes, stiffen their posture, and point their bills upward. Frogmouths imitate their surroundings so well that people looking directly at them think they are looking at branches.

BEHAVIOR AND REPRODUCTION

Frogmouths are crepuscular (kri-PUS-kyuh-lur) and nocturnal, meaning they become active at twilight, just before dark, and in the evening. They rest in trees during the day and hunt for food at night. Birds roost in trees during the day, camouflaged (KAM-uh-flajd) by their color. Since birds hide so well, there is still a lot to learn about some species of frogmouths.

Australian frogmouths build platform-like nests made of sticks. Nests are located in trees, and female Australian frogmouths lay from one to three eggs. The female sits on the eggs, incubating them until they hatch. Both parents feed the chicks.

The Asian frogmouths build a small nest on a branch or tree stem. The nest is constructed of soft feathers called down. Spider webs and tiny lichen plants are placed around the nest to camouflage it. Female Asian frogmouths lay one egg. In some species, the male incubates the egg, sitting on it during the day.

FROGMOUTHS AND PEOPLE

For the most part, frogmouths remain hidden from people and have little relationship with them.

CONSERVATION STATUS

Although frogmouths are not in danger of dying out, loss of habitat could cause a decrease in some frogmouth populations. According to the World Conservation Union (IUCN), changes such as deforestation, cutting down trees, could have an effect on species including the large frogmouth, Gould's frogmouth, and the Bornean frogmouth.

TAWNY FROGMOUTH (Podargus strigoides): SPECIES ACCOUNT

Physical characteristics: Tawny is a brownish yellow color, and this frogmouth species has variations of those colors in their patterned plumage. Like other members of the Caprimulgiformes order, feather colors blend in with the color of trees. This form of camouflage is known as protective coloration.

The upper feathers of male tawny frogmouths are usually gray with black streaks. Lower plumage is a lighter gray, with black streaks and white bars. There may be various shades of brown in the plumage. Female tawny frogmouths have more brown and rufous in their plumage.

Tawny frogmouths have yellow eyes and light brown bills surrounded by bristles. The birds have small legs and feet. The middle toe of each foot is longer than other toes. Tawny frogmouths range in length from 13.5 to 21 inches (34 to 53 centimeters). They weigh from 6 ounces to 1.5 pounds (180 to 670 grams).

Geographic range: Tawny frogmouths are found in Australia and Tasmania.

Habitat: Tawny frogmouths live in all Australian habitats except rainforests where heavy rain produces an abundance of trees that do not shed leaves and deserts where there are no trees. They can be found in grassland areas where there are few trees, deciduous forests where trees shed leaves, plantations of trees planted by people, and tree groves. Tawny frogmouths also live in the gardens of suburban neighborhoods.

Diet: Tawny frogmouths eat insects, worms, slugs, and snails. They also eat frogs, small mammals, reptiles, and birds. The choice of food for these nocturnal birds is based on what prey they can find at night.

Tawny frogmouths usually get their prey by swooping down, flying quickly from their tree perches. Birds use their strong bills to capture prey and then swallow it.

Hungry tawny frogmouths may also fly from their perches and try to capture flying insects like moths. This chase in the air is not just dangerous for the prey, which could be captured in flight. The tawny frogmouth may chase insects illuminated by the car headlights. While the lights help the predator see its prey, the birds often collide with the cars and die.

Behavior and reproduction: Tawny frogmouths usually breed from August to December. However, birds in dry areas may breed after heavy rains. Birds build a platform nest of loose sticks in the fork of a tree branch. The female lays two or three eggs. Both parents incubate the eggs. The male usually incubates during the day. The male may do this because the female is more colorful and would be seen by predators during daylight.

Eggs hatch in about thirty days. Both parents feed the chicks. The young birds fledge, grow their feathers, after thirty to thirty-five days. Tawny frogmouths usually only breed once a year. However, female birds in southern Australia sometimes have two broods, sets of chicks.

Tawny frogmouths and people: People driving at night may unintentionally kill tawny frogmouths that fly in front of their car while hunting flying insects.

Conservation status: Tawny frogmouths are not in danger of extinction, dying out. ∎

FOR MORE INFORMATION

Web sites:

"Red List Text." BirdLife International. http://www.birdlife.org/datazone/downloads/red_list.txt (accessed on June 5, 2004).

"Tawny Frogmouth." Australian Museum Online. http://www.amonline.net.au/factsheets/tawny_frogmouth.htm (accessed on June 1, 2004).

"Tawny Frogmouth." Environmental Protection Agency/Queensland Parks and Wildlife Service. http://www.epa.qld.gov.au/nature_conservation/wildlife/nocturnal_animals/birds/tawny_frogmouth/ (accessed on June 1, 2004).

"Tawny Frogmouth." Honolulu Zoo. http://www.honoluluzoo.org/tawny_frogmouth.htm (accessed on June 1, 2004).