Natural History of Frogs of Sligo Creek

Click on Name to see photo; Click on Location Abbreviations for explanation

.Name Dates
Natural History
Wood Frog 
Rana sylvatica
Adults light, reddish, or dark brown; prominent dark patch (mask) around & behind eyes; tadpoles olive or brown w/greenish tint; eggs packed in sphere like tennis ball, transparent turning dark. Occurs throughout Maryland in or near moist woods, adults often found far from open water in woods (hence Latin & common name); hibernates beneath leaf litter and in rotting wood; can survive complete freezing by producing large amounts of glucose that lowers freezing temperature of cells; breeds farther north than any other frog, above Arctic Circle; enters ponds to breed before all ice is melted; breeding lasts only 2 weeks; males do not defend territories; females can be drowned by overly aggressive mates; pairs stay clasped for 2-3 days; female lays up to 2,000 eggs; eggs hatch in ~3 weeks; tadpoles transform after 40-75 days
Northern Spring Peeper
Pseudacris crucifer
Adults tan, brown, or gray, prominent X-shaped mark (hence Latin name); tadpoles tiny; dark tan top, metallic bronze beneath; eggs single or in small groups, brown on top, attached to underwater plants. Abundant in Maryland deciduous woodland & dense understory, also in coniferous forests, old fields, floodplains, gardens, urban areas. Adults sing weakly on way to breeding on edges of temporary & permanent ponds, reservoir margins, flooded meadows, marshes, swamps, wet meadows, sphagnum bogs, lakes, water-filled ruts. After breeding, adults move to woodlands, fields, shrubby areas; eggs hatch in 1 wk; tadpoles transform after 2 mos. Digits at end of limbs have round, mucus-moistened pads for climbing.. Adults eat spiders, ants, beetles, flies, caterpillars, springtails, pill bugs, mites, ticks, snails; feed on ground and 2-3 ft. up in ferns, high grass, shrubs, trees.
Southern Leopard Frog
Rana sphenocephala
Adults green, brown, or both; large rounded dark spots (hence common name); 2 prominent folds. Mainly in coastal plain, in shallow freshwater ponds, ditches, swamps, but also the margins of lakes & streams; often travel far from water into meadows, fields, pastures; hibernate in larger ponds, streams. lakes buried in mud under water. Breeding females often congregate and lay a few hundred eggs each in numerous clusters; eggs hatch in 1-2 weeks and tadpoles transform ~3 mos.
Striped Chorus Frog
Pseudacris triseriata
Adults gray or brownish; 3 stripes continuous or broken. Occurs widely in Maryland piedmont, upper coastal plain. Breeds in shallow, semi-permanent pools; female lays ~1,000 eggs in clusters of ~60 attached to vegetation. Tadpoles transform after 2-3 months.
Eastern American Toad
Bufo americanus
Adults brown, gray, olive or red; large bumps behind eyes; tadpoles black; eggs in long, twisted, double strings up to 3 feet. Abundant statewide in Maryland woods, meadows, farmland, marshes, gardens, city parks. Breeds in vernal pools, marshes, flooded meadows, lake & river shallows; sings day & night, except during cold snaps. Female lays 2,000-20,000 eggs; hatch in 3-12 days; tadpoles hunt in schools; distasteful to predators; transform after 5-10 weeks; hundred can be found around a pond. Adults wander far from breeding water; live 10+ years. Large glands behind eyes secrete steroid harmful to predators.
Pickerel Frog
Rana palustris
Adults Light brown to olive; 2 rows of dark spots between long folds. Common, statewide in Maryland, prefers cool, clear streams (often in shady mountain ravines), bogs, springs, ponds, lakes, grassy areas near shaded streams. Wanders into grassy fields or weedy areas in summer. Congregates in spring at woodland ponds, bogs, creeks, ditches. Female lays 2,000-3,000 eggs in globular mass attached to underwater plants; eggs hatch in 11-21 days; tadpoles transform after ~3 mos. Adults winter in mud on bottom of ponds, under rocks in damp ravines, sometimes in caves. Adults secrete fluid that repels predators.
Eastern Spadefoot Toad
Scaphiopus holbrookii
Adults gray or brown; 2 wavy yellow lines down the back; tadpoles dark brown w/gold iridescence turns to stripe on thin, short tail w/tiny spots; eggs in easily broken strings. Prefers lowland, sandy habitat on Coastal Plain. Heavy sustained downpour triggers mass migration to breeding pool where in one night they breed, female lays up to 2,500 eggs, and adults depart; eggs hatch after 1-7 days; tadpoles transform in 2-8 weeks. Adults active at night in home range of 70 sq. ft., with 1-7 burrows created by hind feet with horny projection used in digging, hence the name. Can survive extended drought, and loss of 40% body fluid, by enclosing itself in capsule from extruded fluid.
Northern Cricket Frog
Acris crepitans
Adults bright green, russet, yellow, or dark brown or gray; Y-shaped line on back; tadpoles have distinctive black tail tip; eggs laid singly or in small groups attached to plant stems or scattered on bottom. Common in Maryland piedmont, rarely enters coastal plain except along river valleys, prefers open grassy margins of ponds, ditches, marshy areas. Breeds in warm weather in shallow water. Tadpoles transform late summer. Only tree frog that doesn’t climb, adults powerful leapers; escape danger by diving into water and burrowing into muddy bottom. At night, males’ vocal sacs reflect flashlight beam.
Fowler’s Toad
Bufo woodhousii
Adults gray or greenish-gray w/large dark spots & pale center stripe; tadpoles black; eggs in two long strings. Statewide in Maryland, prefers sandy soil of floodplains, river bottoms, lake edges, beaches roadsides, also in open meadows, suburban gardens, farmland, brushy areas, wood edges. Emerge from hibernation only after American toad finishes breeding; breeds in ponds, lake edges, stream backwaters, marshes, dune pools, beaches. Female lays 8,000 eggs; tadpoles hatch in 1 week, transform 1-2 months later. Begins hibernating early autumn, before American toad; overwinters deep in sandy soil.
Green Tree Frog
Hyla cinera
Adults bright or yellowish green back; prominent light side stripes; tiny golden spots. Parts of Maryland piedmont, tidal areas of coastal plain; prefers floating and emergent vegetation along swampy edges of ponds, lakes, marshes, streams. In daytime, rests motionless on cattail plants; at night, sometimes attracted to insects near lights. Female lays 400 eggs amid floating vegetation. Tadpoles transform after 2 months.
Green Frog
Rana clamitans
Adults green, yellow-green, olive, brown, or mixed; ridges from eyes down back; large tympanum (ear drum) behind eye; tadpoles up to 3.5″, olive green w/small black spots; eggs tiny, black in filmy floating egg mass 12″ diam. Statewide and abundant in Maryland in ponds, streams, brooks, marshes, bogs, lake margins, springs, open wooded terrain. Seldom more than a few yards from water. Hibernates in muddy bottom of stream or pond. At breeding, males defend territory 20-30 feet wide. Female lays 3,000-5,000 eggs; early-hatching tadpoles transform late summer; late hatchers over-winter as tadpoles.
Rana catesbeiana
Adults large; olive green, brown, or yellowish; smooth w/out ridges; tadpoles up to 5″, olive; eggs in huge, semi-floating mass up to 2 ft. diam, looking like mat of tiny bubbles . Common in Maryland in larger bodies of water, including lakes, reservoirs, stream & river shallows, backwaters, marshes, floodplain swamps, bogs; fewer in ponds on golf courses & farms, quarry ponds & ornamental ponds. Requires permanent water with submerged & emergent water plants; juveniles sometimes found in temporary ponds or small streams while moving between habitats in wet weather. Wary and solitary. Largest native frog in N. America, grows to 6-8 inches long. Mostly eats insects, spiders, crayfish, & snails, but also ducklings, small turtles, fish, snakes, newts, small frogs, mice. Aggressively defends territory 6-20 feet wide; female lays 6,000-7,000 (sometimes 20,000) eggs; hatch in 3-4 days; males seek new mate after breeding; tadpoles can reach 5-6 inches, hibernate first winter, transform in 12-14 mos.
Gray Treefrog
Hyla versicolor
Adults warty, gray, tinged w/green or brown, dark blotches; brightens or darkens to match surroundings; tadpoles light yellow, matures to olive green with red tail; eggs gray above, single or in globular clusters, on underwater plants. Occurs throughout Maryland coastal plain into upper piedmont. Rarely seen outside breeding season. Begins calling after night temp. reaches 50. Males stake out perches 30″ apart on branches of trees near ponds; females arrive throughout breeding season, eggs scattered groups of 10-40 on surface of shallow ditches, puddles, ponds; hatch in 4-5 days, transform in 45-64 days.

Based on 1998 list compiled by Metropolitan Washington Council of Governments.
Natural history notes adapted from Lang Elliott, The Calls of Frogs and Toads (2004); Bernard Martof, et al, Amphibians and Reptiles of the Carolinas and Virginia (1980), Charles Fergus, Wildlife of Virginia and Maryland and Washington, DC (2003); Thomaas Tyning, Stokes Guide to Amphibians and Reptiles (1990)