A presentation on the citizen science program FrogWatch with information on all Minnesota frog and toad species.

1. Frog and Toad
Data Collection

2. Monitoring Protocol: Upon Arrival
1. Enter volunteer and site information on
the FrogWatch USA Datasheet

3. 2. Record weather (abiotic) information
required on the FrogWatch USA Datasheet
Monitoring Protocol: Upon Arrival

4. Beaufort Wind Scale
Code Definition Speed (mph)
0 – Calm Smoke rises vertically < 1
1 – Light Air Smoke drifts; slight
movement of air
1–3
2 – Light Breeze Leaves rustle; wind felt on
face
4–7
3 – Gentle Breeze Leaves and twigs in
constant motion
8–12
4 – Moderate Breeze Moves small branches,
dust, loose paper
13–17
5 – Fresh Breeze Small trees begin swaying 18–24

5. Reporting Calls and
Intensities Heard
Record any comments under “Additional Notes:”

6. Monitoring Protocol
1. Be quiet for at least 2 minutes before initiating the
monitoring session so frogs and toads acclimate to your
presence.
2. Cup hands around your ears and listen quietly for
precisely 3 minutes. Use a watch to time this duration
accurately.
3. Listen to, identify, and remember all breeding calls
occurring in the session.
If the monitoring session is interrupted by noise,
restart it, including the 2 minute acclimation period.

7. Monitoring Protocol:
Data Submission
• Volunteers share first four datasheets with
chapter coordinators for review
• Submit all datasheets as soon as possible after each
monitoring visit to:
frogwatch@aza.org
or
FrogWatch USA
Association of Zoos and Aquariums
8403 Colesville Road, Suite 710
Silver Spring, MD 20910

8. Frog and Toad
Call Identification

9. Types of Vocalizations
• Advertisement (breeding) call – dominant sound heard
during breeding season.
• Aggressive (agonistic) call – a grunt, growl, or trill
sounded by a male when defending a calling site.
• Release call – a chirp-like sound accompanied by body
vibrations.
• Rain call – Weak version of the advertisement call,
typically following rain events outside the breeding
season.
• Alarm call - a loud squeak emitted as a frog attempts to
escape a predator.

10. Factors Influencing Call Frequency
• Time of year – have a surge in activity
that will decrease as the season
progresses.
• Time of day – peaks after sunset and
tapers off around midnight
• Precipitation – activity tends to increase
following rain events.

11. Factors Influencing Call Quality
• Temperature – the lower (colder) the
temperature, the slower the call.
• Size of individual calling – the larger the
individual, the lower the call.
• Acoustic interference – evidence
suggests that frogs may call higher and
less frequently.

12. • There are 14 species of frogs and toads in
Minnesota
• 3 toads species
• 5 tree frog species
• 6 true frog species
Minnesota Frog Species

13. • Green bars indicate calling and breeding activity in Minnesota.
• Yellow bars indicates species that are very rare in Minnesota.
• Gray area represents FrogWatch seasons
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.
Spring Peeper
Wood Frog
Western Chorus Frog
Boreal Chorus Frog
Bullfrog
Northern Cricket Frog
American Toad
Green Frog
Great Plains Toad
Cope's Gray Treefrog
Northern Leopard Frog
Pickerel Frog
Canadian Toad
Gray Treefrog
Mink Frog
Blanchard's Cricket

14. Size: 2- 4 inches
Skin coloration is typically
brown or reddish. One or two
warts are present in each of
the large dark blotches on
their back. The white chest
usually has dark speckles.
The parotoid gland is typically
separated from the cranial
ridge.
American Toad
(Anaxyrus americanus)
Formerly Bufo americanus
© Jim Harding, MSU

15. American Toad
© USGS
Habitat: Mowed grassy yards
to forested mountains.
Wherever there is abundant
moisture and insects.
Reproduce in virtually any
shallow and fish-free water
body.
Range: Widespread
throughout eastern
North America.

16. American Toad
Voice: A pleasant musical
trill lasting 5 to 30 seconds.
Call sounds like a
simultaneous whistle and
hum.
April– June
© Jim Harding, MSU

17. Green Frog
(Lithobates (Rana) clamitans)
© Rachel Gauza
Size: 2 - 4 inches
Well-developed dorsolateral folds
behind eye helps distinguish from
similar-looking species.
Coloration is similar to the bullfrog but
may be more brown than green.
Breeding males often have yellow-
tinged throat.

18. Green Frog
Range: Widespread
throughout eastern
North America.
Habitat: Lives close to
shallow water, springs,
streams, swamps, brooks,
and edges of ponds and
lakes. May be found
among rotting debris of
fallen trees. © USGS

19. Green Frog
Call: like the twang of a
loose banjo string, usually
given as a single note.
Burst of sound that when
given in rapid succession,
will get progressively quieter.
April - September © Jim Harding, MSU

20. Size: 1 3/8-3 ¼ inches
Dark, masklike patch. Skin coloration is
typically brown, but can range from
reddish-brown to almost black.
The only North American frog found
north of the Arctic Circle.
Habitat: Moist woodlands in eastern
areas; open grasslands in western;
tundra in the far north. Obligate
seasonal pool breeder.
Wood Frog
Lithobates sylvaticus
© National Park
Service

21. Wood Frog
Range: Widespread
throughout northern part
of North America
© USGS

22. Wood Frog
Voice: Series of short raspy
quacks
Listen carefully! Call is
somewhat muted and does
not project or carry very far.
Calling begins as soon as ice
starts melting from the edges of
ponds.
© Jim Harding, MSU

23. Size: 1 ¼ - 2 inches
Gray to creamy white. This frog
can change colors, so it can be
anything from a mottled grayish
green or solid green to a gray or
creamy white color. The inner
thighs on the hind legs of all gray
tree frogs are yellow.
Habitat: Shallow wetlands near
forests during breeding season.
Forests and wooded areas during
the summer.
Gray Treefrog
(Hyla versicolor)

24. Gray Treefrog
Range: Eastern
United States
through Minnesota
and eastern Texas.

25. Gray Treefrog
Voice: A musical, birdlike
trill. The call is similar to
the Cope's gray treefrog,
but slower. They may call
while perched in tree
branches.
May

26. Cope’s Gray Treefrog
(Hyla chrysoscelis)
Size: 1 ¼ - 2 3/8 inches
It looks identical to the gray
treefrog (H. versicolor) but
differs by call and
chromosome count.
Identified by yellow or orange
inner legs and the light
squarish spots beneath the
eyes.
© Dick Bartlett

27. Cope’s Gray Treefrog
Range:
Minnesota South to
Texas and across to
Florida.
Habitat: Trees and
shrubs in or near
ponds or other
wetlands
© USGS

28. Cope’s Gray Treefrog
Call: A hearty, raspy
resonating trill, usually heard
in spring and early summer.
Faster trill that is less
musical than that of the
identical-looking gray
treefrog (Hyla versicolor)
Late March - July
Peaking May - early June © Dick Bartlett

29. Spring Peeper
(Pseudacris crucifer)
Size: ¾ -1 ½ inches
Tan with a dark X on its
back.
Identified by dark “X”
marking on the back that
may appear complete or
broken.
© Paul Crump, Houston Zoo

30. Spring Peeper
© USGS
Range: Common
around the Mississippi
River and east to the
Atlantic Ocean, but
lacking in south-central
Florida.
Habitat: Wooded areas
in or near temporarily
flooded ponds and
swamps.

31. Spring Peeper
Call: High-pitched ascending whistle,
sometimes with a short trill, given once
per second, in a multiple-frog chorus:
peep, peep, peep.
Agonistic call is a sharp prrreep, often
confused with other chorus frog species.
Males call from shrubs and trees near
water or tucked low in emergent
vegetation.
Calling may begin in December and
continues into March/early April © Jim Harding, MSU

32. Size: ¾ - 1 ½ inches
Minnesota’s smallest frog.
Three dark stripes running from
the head down the back. Color
ranges from tan, to grays and
reds.
Habitat: Wetlands and fields near
trees, cities, Breed in shallow
temporary wetlands and ditches
Western Chorus Frog
(Pseudacris triseriata)

33. Western Chorus Frog
Voice: The call of the western
chorus frog is a rising creeee that
sounds like a fingernail being
dragged across a comb.
The western chorus frog sounds
very similar to the boreal chorus
frog but the pulse rate is longer
and slower for the western chorus
frog.
March - April

34. Size: 1 - 1 ½ inches
Very similar in appearance to the
western chorus frogs but legs are
shorter. Brown, olive, tan, or
green with a prominent black
stripe on each side from the
nostril through the eye and down
the sides. Dark stripes down the
back
Habitat: Shallow and temporary
pools, moist meadows and forests
near wetlands
Boreal Chorus Frog
(Pseudacris maculata)

35. Boreal Chorus Frog
Voice: The call of the
boreal chorus frog sounds
like a fingernail being
dragged across a comb.
March - April

36. Chorus Frogs
Range: Across
eastern and central
North America from
Easter Texas
Through Northern
Canada.

37. Size: 2-3 inches
The mink frog is blotchy green
and brown with a pale underside
and a conspicuous tympanum
(eardrum). Males may have a
bright yellow throat.
Habitat: Mink frogs prefer lakes
and rivers with water lilies. Which
they use to hide from predators
and will hope along the top.
Mink Frog
(Rana septentrionalis)

38. Mink Frog
Range: Across
the Northeast part
of the United
States from
Minnesota to
Maine and into
Canada.

39. Mink Frog
Voice: A rapid cut, cut, cut
resembling a hammer
striking wood. When mink
frogs call in chorus it sounds
like horses' hooves on a
cobblestone road.
May- July

40. Size: 2-3.5 inches
Once the most widespread frog in
North America.
Leopard frogs receive their name
from the leopard like spots on
their body.
Habitat: Wet meadows, open
fields, and forest edges near
wetlands. Will breed in marshes,
wetlands, and fishless ponds.
Northern Leopard Frog
(Rana pipiens)
© MN DNR

41. Northern Leopard Frog
Range: Northern
Midwest from the
Dakotas through
Ohio. A separate
population ranges in
the northern New
England states.

42. Northern Leopard Frog
Voice: A long, deep
snore lasting several
seconds and ending with
a chuckling (chuck-
chuck-chuck)
Late April- May
© USFWS
Minnesota State
Amphibian

43. FREQUENTLY USED
REFERENCES
• Consult local resources (e.g., State Dept. of Natural Resources, State Wildlife Agency, State Atlas, etc.)
• FrogWatch USA Species by State Lists: http://www.aza.org/states-and-territories
• National Amphibian Atlas: http://www.pwrc.usgs.gov/naa
• USGS Frog Call Look Up and Quiz: http://www.pwrc.usgs.gov/frogquiz
• Cornell Lab of Ornithology, Macaulay Library (of Natural Sound): http://macaulaylibrary.org/
• Western Soundscape Archive: http://westernsoundscape.org
• eNature: http://www.enature.com
• AmphibiaWeb: http://amphibiaweb.org
• International Union for the Conservation of Nature Red List - Amphibians: http://www.iucnredlist.org/initiatives/amphibians
• NatureServe Explorer: http://www.natureserve.org/explorer
• USGS Checklist of Amphibian Species and Identification Guide: http://www.nwrc.usgs.gov/sc_armi/frogs_and_toads/index.html
• The Frogs and Toads of North America. Lang Elliott, Carl Gernhardt, and Carlos Davidson. Houghton Mifflin Company, 2009.

44. Frogs and Toads of the Cabin
Regions

45. Size: 2- 3 ½ inches
Skin coloration is gray, brown, or
greenish. It has large blotches
which have a strongly contrasting
white border. The blotches
contain several small warts. The
chest is white with no speckles.
Habitat: Damp areas in
grasslands and open fields.
Great Plains Toad
(Bufo cognatus)

46. Great Plains Toad
Range: The Great
Plains region

47. Great Plains Toad
Voice: Great plains toads
produce a loud, metallic
trill that can last more than
20 seconds.
Spring- Summer
Breeding activity is
triggered by warm, heavy
rains

48. Size: 2- 3 ½ inches
The Canadian toad is brown to
green with darker brown, reddish,
or black spots. Its underside is
light with dark flecks, especially
on the throat.
Habitat: Shallow wetlands,
streams, and roadside ditches. In
summer months found near
prairie wetlands.
Canadian Toad
(Bufo hemiophrys)

49. Canadian Toad
Range: Northwestern
Minnesota through
eastern North Dakota up
through eastern Alberta
and southwestern
Manitoba

50. Canadian Toad
Voice: A clear trill very
similar to the American
Toad, but lower in pitch
and shorter, lasting
approximately five
seconds.
May- June

51. Size: 1¾ - 3 inches
The pickerel frog has a pale
brown background with brown
spots in rows on back. Its
underside is light-colored with
yellow where the legs and body
connect.
Habitat: Slow-moving waters and
other damp areas preferably with
low, dense vegetation; streams,
swamps, and meadows
Pickerel Frog
(Lithobates (Rana) palustris)
© Jim Harding, MSU

52. Pickerel Frog
Range: Throughout the
East Coast, except in
the very Southeast
© USGS

53. Pickerel Frog
Voice: Steady, low, snore-
like croak. Raspy in quality
and may last up to 2
seconds. Similar to the
leopard frog without the
chuckle at the end.
May call in a rolling snore
while under water.
April-May
© USFWS

54. Size: 3 – 8 inches.
The largest frog in North America.
Green skin coloration with yellow
throat in males and white in females.
Habitat: Ponds, lakes, slow-moving
streams with vegetation. (Must be
large enough to avoid crowding).
© Jim Harding, MSU
American Bullfrog
Lithobates catesbianus
(formerly Rana catesibana)

55. © USGS
American Bullfrog
Range: Widespread
throughout the United States.
Native to eastern US;
introduced in the west.

56. American Bullfrog
Call: Deep-pitched “jug
o'rum” resembling the
bellow of a bull.
Call can be heard for more
than a quarter mile.
March - September
© Jim Harding, MSU

57. Size: 5/8 - 1 ½ inches
Among the most agile leapers
and can jump surprisingly long
distances (5 - 6 feet) for its
small size.
Have greatly reduced toe
pads, webbed toes, and long
legs.
Skin appears warty and
coloration is highly variable.
Northern Cricket Frog
(Acris crepitans crepitans)
© Jim Harding, MSU

58. Northern Cricket Frog
Range: Southern New York
to Florida panhandle; west
to Texas.
Habitat: Sunny ponds of
shallow water with good
growth of vegetation in the
water or on the shore; slow-
moving streams with sunny
banks.
© USGS

59. Northern Cricket Frog
Call: Sharp, measured clicking,
repeated in rapid succession.
Call reminiscent of two glass marbles
being tapped together or the shaking
of a spray paint can.
March- August
© Jim Harding, MSU

60. Size: .6- 1 ½ inches
They have warty skin that is tan, brown,
gray or olive. With a broad light stripe
down the back. A dark triangular mark is
usually visible between the eyes on top
of the head.
Habitat: Open edges of permanent
ponds, lakes, bogs, seeps and slow-
moving streams and rivers. They prefer
open or partially vegetated mud flats,
muddy or sandy shorelines, and mats of
emergent aquatic vegetation in shallow
water. Cannot tolerate any pollutants.
Blanchard’s Cricket Frog
(Acris crepitans blanchardi)

61. Blanchard’s Cricket Frog
Range: Eastern
United States. Small
populations in
Hennepin and
Winona Counties.
Documented in
Chisago County in
1967.

62. Blanchard’s Cricket Frog
Voice: Metallic clicking
call, similar to the sound
made when two pebbles
are tapped together.
May- July
Very Rare!
Classified as Endangered in
Minnesota