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The Handbook: Prevention and Control of Wildlife Damage Management, Internet Center Wildlife Damage for

January 1994

FROGS AND TOADS

Paul E. Moler Wildlife Biologist, Florida Game and Fresh Water Fish Commission, Wildlife Research Laboratory, Gainesville, Florida 32601

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Moler, Paul E., " AND TOADS" (1994). The Handbook: Prevention and Control of Wildlife Damage. 78. https://digitalcommons.unl.edu/icwdmhandbook/78

This Article is brought to you for free and open access by the Wildlife Damage Management, Internet Center for at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in The Handbook: Prevention and Control of Wildlife Damage by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Paul E. Moler Wildlife Biologist Florida Game and Fresh Water Fish FROGS AND TOADS Commission Wildlife Research Laboratory Gainesville, Florida 32601

Fig. 1. Great Plains toad, cognatus

Damage Prevention and Habitat Modification Trapping Control Methods Around hatchery ponds, keep vegeta- Funnel traps. tion closely mown and remove Capture Exclusion emergent vegetation and other types of cover. Capture by hand or gig at night. Seal all openings 3/16 inch (0.5 cm) or larger to exclude frogs. Frightening Egg masses may be removed with a fine-meshed net. A frogproof fence can be used for Not applicable. Shooting nonclimbing species, but will be in- Repellents effective against treefrogs and a few Allowed in some states, but often not None are registered. related species. safe in areas requiring control. On fish farms, mesh tenting over Toxicants Some states permit shooting only during daylight hours. ponds will serve to exclude frogs as None are registered. well as birds and other predators. Fumigants None are registered.

PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994 Cooperative Extension Division Institute of Agriculture and Natural Resources University of Nebraska - Lincoln Department of Agriculture and Plant Health Inspection Service Animal Damage Control F-9 Great Plains Agricultural Council Wildlife Committee Identification mice, and small birds. In natural habi- tions of the west has seriously affected tats, fish usually comprise less than 5% some native species. In at least some Frogs and toads are with of the diet of the bullfrog. On fish cases, these introductions may have four legs and no tail. They may have farms, as many as 30% of bullfrogs resulted from the unintentional release skin that is smooth and moist or dry have been found to contain fish. of tadpoles during fish-stocking pro- and warty, but they have no scales or grams. Considerable labor is required claws. The front legs are short, but the General Biology, to separate tadpoles from loads of fry. hind legs are muscular and elongated Reproduction, and Only in rare instances do frogs cause for hopping or jumping. The popular Behavior any significant damage. Some species distinction between frogs and toads is (toads, for example) produce skin somewhat artificial; basically, toads Although some species spend most of secretions that are toxic if ingested. are a particular group of frogs. their adult lives away from water, This does not normally present a prob- Throughout this chapter, the term most frogs native to North America lem for people, and pets usually learn will be used to include toads. North must return to water to lay eggs. Some to avoid such frogs. A few species American frogs range in body size species breed during the cooler winter (giant toad, Colorado River toad) pro- from the 11/16-inch (1.7-cm) little and spring months, whereas others duce especially copious or toxic secre- grass frog to the 8-inch (20-cm) bull- breed during the warmer months. Fol- tions, and there have been cases in frog. lowing rain, males begin calling from which have died after biting breeding sites. Each species has its them. Range own distinctive call, and females The noise sometimes produced by respond only to the calls of their own large breeding choruses of frogs fol- At least 85 species of frogs are native species. Several recordings of frog calls lowing heavy rains can be annoying to to the United States, and there are are available, and four are listed at the humans. These aggregations usually three well-established exotic species. end of this chapter. last only a few days, however, and sel- There is no part of the country that is Eggs are fertilized by the male as they dom warrant control. Similarly, com- not home to at least a few species. are released by the female. Hatching plaints sometimes arise when large occurs a few days later. The aquatic numbers of young frogs leave the Habitat tadpole stage may last as little as 2 to 3 ponds en masse, but the frogs disperse weeks in some species of spadefoots or quickly, and the “problem” will take Frogs occur in almost all nonmarine as long as 2 years in some northern care of itself in a few days. habitats. “True” frogs (genus Rana) populations of bullfrogs. and treefrogs predominate in the more humid east. In the drier Great Plains Frogs are typically most active at Legal Status and western regions, toads and night. Some species aggregate around spadefoots are typically more numer- artificial lights and feed on the insects Laws pertaining to frogs vary from ous. Whereas some species are seldom attracted there. Frogs are an important state to state. Some rare species (for found far from permanent water, component of the vertebrate food example, Houston toad, Wyoming others return to water only seasonally chain and are consumed by a variety toad, Pine Barrens treefrog) may be to breed. Some species spend of predators, including fish, snakes, fully protected under federal or state most of their time beneath ground, turtles, wading birds, raptors, skunks, laws. Seasons and bag limits may venturing to the surface only following and . Individuals of many apply to other species (bullfrogs, for rains. species may live 12 to 15 years, but life example). Permits to remove frogs that expectancy is much shorter in the are causing damage are available in Food Habits wild. some states. Contact your state wildlife department to determine the legal Most frogs have a two-phased life Damage status of frogs in your area. cycle, including an aquatic larval form The greatest potential for economic (tadpole) and a terrestrial or semi- damage is at fish farms and hatcheries. Damage Prevention and aquatic adult form. Tadpoles are pri- Tadpoles compete for food intended marily herbivorous, feeding on algae Control Methods for fish, and adult bullfrogs may actu- and decaying organic matter. Adults, ally feed on the fish. Losses are said to on the other hand, are carnivorous, Exclusion be high at some fish farms. One study consuming almost any prey that can be suggested that the mere presence of The effectiveness of exclusion depends overpowered. Although the diet con- high densities of tadpoles retarded in part on the species involved. Most sists primarily of insects, crayfish, and reproduction of fish. Although the species responsible for potential or real other invertebrates, larger frogs occa- bullfrog is native to most of the eastern damage can be effectively excluded sionally take snakes, other frogs, fish, United States, its introduction to por- from limited areas. Giant toads (south-

F-10 ern Florida, extreme southern Texas) Caution: traps may capture other non- Acknowledgments or Colorado River toads (southern target species, including snakes, , extreme southeastern Califor- turtles, and small mammals. Figure 1 by Randy Babb, Arizona Game and nia) can be excluded from pet enclo- Fish Department. sures by placing a strip of 1/8-inch Capture (0.3-cm) mesh hardware cloth along Frogs can be located at night by the re- For Additional the outside base of the perimeter fence. flection of their eyes in the beam of a Information The hardware cloth should be buried headlamp. They can be collected by at least 4 inches (10 cm) in the ground gig or hand. Captured frogs may be and should extend to a height of at Altig, R. 1970. A key to the tadpoles of the eaten, or where allowed by law, sold continental United States and Canada. least 20 inches (50 cm). A similar exclu- to provide additional economic Herpetol. 26:180-207. sion fence can be used to control returns. Check with your state wildlife breeding aggregations of nonclimbing Bogert, C. M. Sounds of North American frogs: agency regarding seasons, bag limits, the biological significance of voice in frogs. species in small, urban stormwater legal methods of take, and restrictions (Record or cassette. Calls of 50 species.) detention basins or to exclude these on sale. Distributed by Rounder Records, species from small hatchery ponds. Cambridge, Massachusetts, and Smithsonian Although treefrogs and some related Shooting Folkways Records, Rockville, Maryland. species will readily climb such a fence, Boyd, S. H. 1975. Inhibition of fish reproduction most treefrogs normally breed in sea- Although shooting is allowable in by Rana catesbeiana larvae. Physiol. Zool. 48:225-234. sonal, fish-free waters. In addition, some states, it is not safe in some areas their eggs and tadpoles are readily requiring control. Conant, R., and J. T. Collins. 1991. A field guide eaten by fish, so they do not usually to reptiles and amphibians: eastern and central North America. Houghton Mifflin present a significant problem on fish Economics of Damage Co., Boston. 450 pp. farms. and Control Corse, W. A., and D. E. Metter. 1980. Economics, Habitat Modification adult feeding and larval growth of Rana Frogs eat many insect pests. With the catesbeiana on a fish hatchery. J. Herpetol. Keep the shoreline of ponds free of exception of fish farms, control mea- 14:231-238. emergent vegetation to minimize cover sures for frogs are seldom warranted Duellman, W. E., and L. Trueb. 1986. Biology of for adult frogs and allow predators to and, in most cases, should be discour- amphibians. McGraw-Hill Book Co., New York. 670 pp. assist in control. Efforts to directly aged. On fish farms, the economic remove adult frogs at night will also be damage depends in part on the unit Elliot, L. 1992. The calls of frogs and toads: facilitated. value of the fish produced. Corse and Eastern and Central North America. (Cassette and booklet. Calls of 42 species.) Metter (1980) provided data suggest- Frightening Chelsea Green Pub. Co. Post Mills, Vermont. ing that a 350-pond farm that pro- Johnson, T. R. Talking toad and frog poster and Not applicable. duced goldfish might sustain $42,000 cassette. (Includes 20 frogs found in in annual losses to bullfrogs, whereas Missouri.) Missouri Dep. Conserv., Jefferson Repellents the same facility might sustain only City. None are registered. $12,600 in losses if it produced golden Kellogg, P. P., and A. A. Allen. Voices of the shiners, a less valuable species. It fol- night. (Calls of 34 species found in eastern Toxicants lows that losses might be still higher North America). Houghton Mifflin Co. (for on farms specializing in valuable the Cornell Lab. Ornith.), Boston. None are registered. aquarium fishes. Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin Fumigants Co., Boston. 336 pp. None are registered.

Trapping Place funnel traps along the base of a Editors Scott E. Hygnstrom perimeter fence. Toads may also be Robert M. Timm trapped by burying several 5-gallon Gary E. Larson (19-l) buckets flush with the ground surface beneath an overhead light. Toads attracted by the insects drawn to the light will fall into the buckets and be unable to escape.

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