The bird-voiced treefrog Hyla avivoca is most commonly found in deep wooded swamps with emergent woody vegetation in the south-eastern United States (Knapp 2001, Behler 1979).

Biogeographic Regions: nearctic (Native )

endemic to a single nation

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) Southern Illinois and western Kentucky to Gulf Coast, Louisiana to Florida Panhandle, eastern Georgia, and adjacent South Carolina; west of the Mississippi River, occurs disjunctly in central and northern Louisiana, southeastern Oklahoma and adjacent southwestern Arkansas, and central Arkansas (Conant and Collons 1991).

Adult length 28 mm to 51 mm (1.25 inches to 2.25 inches).

The backs of bird-voiced treefrogs are gray, brown or green, often have one or more dark spots and have a warty surface. They have light, sometimes white, spots under their eyes. They have large toe pads, with adhesive disks on the tips of their digits. The hidden surfaces of their thighs and groin area usually range from light green to white and they have dark bars on their hind legs. The species is dimorphic, females are usually larger than the males. The males range in size from 28 mm to 39 mm (1.25 inches to 1.75 inches) and the females range from 32 mm to 51 mm (1.5 inches to 2.25 inches). The males have a darker throat pouch than the females. The tadpoles, prior to metamorphosis, are black and have several orange bands on their tails and an orange spot on their heads. (Wright 1949, Northern Prairie Wildlife Research 2001, Georgia Museum 2000)

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Length: 5 cm

• Terrestrial
• Freshwater

Bird-voiced treefrogs prefer swamps and brushy areas and are usually found in trees that grow in water. (Georgia Museum of Natural History 2000)

Terrestrial Biomes: forest

Comments: Permanent wooded swamps (tupelo, cypress, birch, buttonbush, and vine tangles) bordering rivers and streams. May climb high into trees. Generally intolerant of impoundments that flood habitat. Males call from trees, shrubs, and vines that are in or next to water. Eggs and larvae develop in swamp pools.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Bird-voiced treefrogs are opportunistic feeders. Their diet consists mainly of spiders and small arboreal insects. They typically hunt for their prey by foraging about in trees and shrubs. (Illinois Department of Natural Resources 1998)

Comments: Metamorphosed frogs probably eat various small arboreal arthropods. Larvae eat organic debris, algae, and plant tissue.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 - 300

Comments: Ashton and Ashton (1988) recorded occurrences in 10 counties through the species' range in western Florida. Moler (1992) did not include this species in his review of the rare and endangered herpetofauna of Florida, suggesting an ample number of occurrences. Dundee and Rossman (1989) mapped about 65 locations in Louisiana, where the species appears to be widespread east of the Mississippi River. Widespread in the Coastal Plain in southern and western Alabama, where Mount (1975) mapped 36 collection sites. Occurs in suitable habitats throughout Mississippi (Ferguson 1961, see also Smith 1966). Redmond and Scott (1996) mapped 14 locations in Tennessee. In Illinois, recently known from 4 counties, with one additional pre-1980 county occurrence (Phillips et al. 1999). During 1992-2000, 7 new county records (3 in Georgia, 2 in Louisiana, 1 each in Tennessee and Florida) were published in Herpetological Review, suggesting that the distribution is fairly well known but still not completely documented.

10,000 - 1,000,000 individuals

Comments: Total population size is unknown but surely exceeds 10,000 adults. Most state herpetology accounts mention the existence of large populations. In South Carolina, Gibbons and Semlitsch (1991) noted "large choruses" in three locations on the Savannah River Site, plus additional smaller populations. Bartlett and Bartlett (1999) rated this species as common to abundant in Florida. Barbour (1971) noted the occurrence of a "magnificant population" in some of the swamps in Hickman County, Kentucky. Redmond and Scott (1996) stated that this species is especially abundant around Reelfoot Lake in Tennessee. "Locally common in some good habitats" in the limited range in extreme southern Illinois (Phillips et al. 1999). Abundant in floodplain swamps in western Union and Alexander counties, Illinois (Smith 1961:87.)

Comments: Seldom observed outside breeding period.

Average lifespan

Status: captivity: 2.5 years.

Bird-voiced treefrogs are considered late breeders, usually breeding from June to mid-August. The eggs are layed in shallow water in packets of 6 to 15 eggs. Females lay, on average, a total of 500 to 650 eggs. The eggs will hatch into tadpoles usually within a few days. The tadpoles will develop into adults within approximately one month. The tadpoles transformed size is approximately one-half inch. Breeding is usually increased with heavy rains. (Knapp 2001, Georgia Wildlife 2000, Auburn University 2001)

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous

Lays clutch of several hundred eggs, distributed among small clusters, in spring or summer (peak toward end of May in South Carolina). Aquatic larvae hatch in a few days, metamorphose in about one month.

Bird-voiced treefrogs are classified as a threatened species in the state of Illinois. This is the northern most portion of the species' range, and these frogs occur only in a few cyprus swamps in the extreme southern tip of Illinois. It is listed as threatened because it occurs only in these few locations. Its population can be affected by any river damming or swamp drainage that causes changes to swampy land. (Georgia Museum of Natural History 2000)

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Moderately widespread in southeastern United States; locally abundant; apparently stable range and abundance in most areas; not threatened in most of range.

Intrinsic Vulnerability: Moderately vulnerable

Environmental Specificity: Moderate to broad.

Other Considerations: Ranked by states as secure (S5) in the main part of the range; high ranks only in peripheral states.

Global Short Term Trend: Relatively stable (=10% change)

Comments: Apparently stable; no evidence of a decline in recent decades.

Global Long Term Trend: Increase of 10-25% to decline of 50%

Comments: Likely relatively stable in extent of occurrence, unknown degree of decline in population size, area of occurrence, and number/condition of occurrences.

Degree of Threat: C : Not very threatened throughout its range, communities often provide natural resources that when exploited alter the composition and structure over the short-term, or communities are self-protecting because they are unsuitable for other uses

Comments: Swampy habitat protects the species from many threats deriving from habitat alteration, but threats include clearing and draining of baldcypress-tupelo swamps (Phillips et al. 1999).

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: Likely there are at least several protected occurrences.

None Known

By eating small insects these frogs may keep pests populations lower.

Comments: Nominal subspecies generally are not recognized in recent literature.