Hyla avivoca

Geographic Range

Bird-voiced treefrogs ( Hyla avivoca ) are native to the southeastern portion of the United States. This species is most commonly found in states bordering the Mississippi River, as far west as Oklahoma, as far east as Florida and as far north as Illinois. They are concentrated in Mississippi, Alabama, Tennessee and Georgia, and located as disjunct populations throughout central Arkansas, central and eastern Louisiana, and eastern Oklahoma. Bird-voiced treefrogs are found in the southern region of Illinois but are also listed as endangered in this state.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Bird-voiced treefrogs live in swampy conditions near rivers and streams in the temperate forest region. Males are most commonly found perched up in trees about 0.5-2.5m above the water's surface just before breeding season begins. Bird-voiced treefrogs are most commonly found in wooded swamps along rivers and streams mainly consisting of baldcypress ( Taxodium distichum ), buttonbush ( Cephalanthus occidentalis ), and tupelo ( Nyssa ) They also can be found lower to the ground in small shrubs or in an opening at the base of a tree's trunk. During early stages of development, larvae and tadpoles inhabit shallow pools of freshwater.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial
• freshwater freshwater

• Terrestrial Biomes
• forest forest

• Aquatic Biomes
• rivers and streams

• Wetlands
• swamp swamp

• Other Habitat Features
• riparian riparian

Physical Description

Bird-voiced treefrogs are a tree-dwelling species that rely on their physical appearance for protection and reproduction. Males’ snout-vent length can range from 2.8-3.9 cm with females being slightly larger at 3.2- 5.2 cm. They have smooth skin with a mucous covering that helps limit water loss while perched in trees above rivers and streams. Their feet are webbed and have special adhesive padding qualities for climbing. Like most treefrog species, bird-voiced treefrogs have bulging eyes with rounded snouts and small white spots on the skin inferior to the eyes. This species tone varies from brown to grey mixing with green and black blotching specifically localized on the dorsal region. Their limbs have dark stripes and can either be a grey or green-yellow color. The ventral side of bird-voiced treefrogs is pale white with dark spots in the anterior region.

Bird-voiced treefrog tadpoles have been recorded in lengths up to 3.5 cm. They have long black tails with copper markings and a pointed tip. Their tail fins are grey and spotted with black.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Development

Bird-voiced treefrog females release eggs, which are externally fertilized by males. The eggs of bird-voiced treefrogs tend to be a dark brown and cream color, and are comprised of the ovum and two layers surrounding the ovum. These eggs are found submerged in water, in the sediment of rivers and streams, attached to gravel by the sticky jelly coat that surrounds their outer layer. Hatchlings employ periodic muscle contractions to work their way out of the gelatinous egg. Once out, they are capable of swimming.

The first stage of growth preceding hatching is the construction of the gills on the tadpole and the development of teeth. The larval period for Hyla avivoca will last up to 30 days after hatching. During this time the tadpole experiences rapid growth. At the start of metamorphosis the hind limbs begin to develop, starting out as a small bud with the toe pads forming first and eventually developing into full hind appendages. Once these appendages are developed, the tadpole is able to start the metamorphic process. Once this process begins, the tadpole starts to develop anterior appendages, the tale begins to shorten, and the head becomes more distinct. Eventually the tail disappears completely and the tadpole reaches full adult growth.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Bird-voiced treefrog mating season begins in late spring (April and May) and continues through much of the summer (June-August). Reproductive maturity of female bird-voiced treefrogs begins anywhere between years 2-4 of life. These frogs have a polygynandrous system of mating, meaning males and females have multiple mating partners. Mating preference is determined by call competition among males to win over females. The call of the males is stimulated by the warming of temperatures in the spring (about 20 degrees Celsius), and males can begin calling up to a month before breeding even begins. Male bird-voiced tree frogs produce a bird-like call while perched in trees above water, while the females remain at ground level. Male competition is displayed by pulsing rhythm sounds and length of call time. Gerhardt and Martinez-Rivera (2008) found that males lacking competition had an average of about five calls per minute. When the males were competing against one another, their calls averaged at about six calls per minute and their pulsing call rhythms alternated between each competing male. In areas where there were multiple possible male mates (averaging 2.5 meters apart), the females reacted to the male with the longest call frequency.

When the females detect a distinguishable call, neurons are then stimulated displaying phonotactic behavior to approach the male. After the initial approach, the male will latch onto the dorsal side of the female, and they? will then migrate as one down from the perching site to water. The female then begins to deposit her eggs into the water where they will begin developmen

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

In a typical breeding season female < Hyla avivoca > will produce 409 to 811 eggs (average 632). Female bird-voiced treefrogs reach sexual maturity at 2-4 years old and are iteroparous, breeding once a year for the rest of their lives. Ovulation in females occurs spontaneously and is stimulated by males’ calls. Age of sexual maturity for males has not yet been determined. The time from when the eggs are fertilized to when they hatch averages around 2 days. Once hatching occurs, the tadpoles metamorphose after 30 days

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• fertilization fertilization
  • external external
• oviparous oviparous

There is no parental investment from bird-voiced tree frogs after the eggs have been deposited in water.

• Parental Investment
• no parental involvement

Lifespan/Longevity

In the wild, female bird-voiced treefrogs have been known to live as long as 4 years. Male bird-voiced treefrog lifespan is unknown. No information has been reported on the lifespan of bird-voiced treefrogs in captivity, because they are not known to be kept in captivity.

Behavior

Bird-voiced treefrogs remain mostly as a solitary species except during mating season when they interact and communicate for reproduction. Their biggest distinctive behavior is the males’ vocalizations during called of females. Bird-voiced treefrogs are motile and have feet adapted for climbing trees providing them with their scansorial behavior. Males climb to find perching sites where they will send out their calls during breeding seasons. Males and females will also use their ability to climb and jump in order to scavenge for insects on the bark of trees. Females remain mostly terricolous spending their time under logs, in shrubs, and in other ground vegetation. No migratory patterns of Hyla avivoca are known. Many scientists believe this species of treefrog remains sedentary throughout of their life. Behavior of tadpoles is primarily natatorial until they begin to develop legs and lungs.

• Key Behaviors
• scansorial
• terricolous
• saltatorial saltatorial
• natatorial natatorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• solitary solitary

Home Range

Home range has not been reported for this species. It appears that males defend an unspecified territory during the breeding season, as male-male battles have been reported on calling perches.

Communication and Perception

Bird-voiced treefrogs communicate primarily for mating purposes. Male bird-voiced treefrogs communicate with their potential mates through their unique birdlike call. Females are better attracted to shorter low-pitched calls when only a single male is present, but when males call in a group chorus the females choose mates with long, higher pitched calls. Gerhardt and Martinez-Rivera (2008) found that males display a unique technique of calling when competing with other males called pulse interdigitation. This technique works by each frog altering its calls to where the pulse call frequencies do not overlap but instead integrate within each others calls. This uniquely identifies each male in a chorus and facilitates mate selection. Females will approach a calling male and, once paired, will reproduce and migrate to water to deposit the eggs. Male bird-voiced treefrogs also can display competitive behavior and communicate with other competitors that come too close by vocalizing a high-pitched call as a warning. Tactile sense during mating is perceived by the males behavior to latch on the the female dorsal. It has not been reported in this species, but other species in this genus use chemosensory behavior to avoid predators during periods of calling.

• Communication Channels
• acoustic acoustic

• Other Communication Modes
• choruses choruses

• Perception Channels
• acoustic acoustic

Food Habits

Bird-voiced treefrogs are insectivores that forage primary at night and on arboreal arthropods. Jamison et al. (1999) inspected the digestive contents in 14 female bird-voiced treefrogs and showed that they contained insect species such as elaterid beetles (Elateridae), chrysomelid beetles (Chrysomelidae), homopterans, and moth and butterfly larvae. Based on the type of insect species these frogs are consuming suggest that bird-voiced treefrogs forage while perched in trees.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods

• Animal Foods
• insects
• terrestrial non-insect arthropods

Predation

No scientific studies and observations report specific predators of bird-voiced treefrogs, but it is believed, like most tree frog species, juveniles and adults are preyed on by water snakes, birds, and other vertebrates (Lannoo, 2005). Their brown and green tinting of the skin displays a cryptic form of adaptation by matching with their environment.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Although the predators of this species are unknown, Lannoo (2005) suggested they are preyed upon by birds, water snakes, and other vertebrates. Bird-voiced treefrogs are predators of arboreal arthropods. Jamieson et al. (1993) observed 61 juvenile and adult bird-voiced treefrogs, and found that they were infected with protozoans and platyhelminths. Specific species of protozoans include Tritrichomonas augusta , Opalina , and Nyctotherus cordiformis . Platyhelminth parasites include Megalodiscus temperatus , Cylindrotaenia americana , Abbreviata , Batracholandros bassii , and Oswaldocruzia pipiens .

Economic Importance for Humans: Positive

There is no known information regarding the positive economic benefits of bird-voiced treefrogs for humans.

Economic Importance for Humans: Negative

There are no known adverse effects in the economic importance of bird-voiced treefrogs.

Conservation Status

According to IUCN Red List, the range of bird-voiced treefrogs include state and federal government lands that are fairly secure. Bird-voiced treefrogs are listed as threatened in the state of Illinois, due to the species existing in isolated pockets. Because these isolated pockets restrict interaction, genes are not shared and long-term reproductive success could be impacted. This treefrog species also inhabits bottomland hardwood swamps and forested floodplains; if these lands are cleared or drained, the frogs are forced out of their habitat, and their chances of survival decreases.

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

Danielle Cyburt (author), Radford University, Alex Atwood (editor), Radford University, Marisa Dameron (editor), Radford University, Karen Powers (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Fulmer, T., R. Tumlison. 2004. Important records of the bird-voiced treefrog (Hyla avivoca) in the headwaters of the Ouachita River drainage of southwestern Arkansas. Southeastern Naturalist , 3/2: 256-266.

Gerhardt, C., C. Martínez-Rivera. 2008. Advertisement-call modification, male competition, and female preference in the bird-voiced treefrog Hyla avivoca. Behavior Ecology & Sociobiology , 63/2: 195-208.

IUCN SSC Amphibian Specialist Group, 2014. "Hyla avivoca" (On-line). The IUCN Red List of Threatened Species version 2014: e.T55403A64265196. Accessed September 15, 2016 at http://www.iucnredlist.org/details/55403/0 .

Jamieson, D., C. McAllister, S. Trauth, S. Upton. 1993. Endoparasites of the bird-voiced treefrog, Hyla avivoca (Anura: Hylidae), from Arkansas. Journal of the Helminthological Society , 60/1: 140-143.

Jamieson, D., M. Redmer, S. Trauth. 1999. Notes on the diet of female bird-voiced treefrogs (Hyla avivoca) in southern Illinois. Transactions of the Illinois State Academy of Science , 92/3&4: 271-275.

Lannoo, M. 2005. Amphibian Declines: The Conservation Status of United States Species . Los Angeles, California: University of California Press.

Volpe, P., M. Wilkens, D. James. 1961. Embryonic and larval development of Hyla avivoca. Copeia , 1961/3: 340-349.