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FINAL REPORT
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ANALYSIS SPECIES ASSESSMENT:
Red-legged Frog (Rana aurora aurora)
RELICENSE STUDY T-4
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FERC PROJECT NO. 2150
Prepared by:
19997 Hwy 9
Mount Vernon, WA 98274
Phone: (360) 422-6510
Prepared for:
Puget Sound Energy
Baker River Project Relicense
Wildlife and Terrestrial Resources Working Group
February 21, 2003
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Unpublished Work © 2003, Puget Sound Energy, Inc.
Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
Baker River Terrestrial Working Group Analysis Species
Red-legged Frog (Rana aurora aurora)
Drafted by Danielle Flath, Sarie Nichol and Frank Lapsansky
Habitat Type: Wetland/Riparian Species
Species Biology and Population Status:
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The red-legged frog (Rana aurora) is a medium to large sized frog found west of the
coastal mountain ranges of western North America from Southern British Columbia
to the northern Baja Peninsula of California (Green and Campbell 1984).
The northern subspecies, R. aurora aurora occurs from southwestern British
Columbia, through Washington and Oregon and into northern California, where it
intergrades with the California subspecies (R. aurora draytonii) in Mendocino
County, California (Nussbaum et al. 1983, Hayes and Miyamoto 1984).
Adult females typically measure approximately 100 mm (3.9 inches) snout-to-vent
length, while males are considerably smaller, measuring around 70 mm (2.8 inches)
snout-to-vent length (Nussbaum et al. 1983).
Eggs are in a soft grapefruit to cantaloupe- sized mass and may be laid close together
but not on top of each other (Corkran and Thomas 1996). The egg mass is generally
15 to 25 cm (0.6 to 1.0 inches) in diameter, and contains 500 to 1,100 eggs
(Nussbaum et al. 1983).
A unique identifying characteristic of the red-legged frog is coloration of the hind leg
underside. It is translucent red in adults and pale pink in juveniles (Corkran and
Thomas 1996).
R. aurora can be found in elevations ranging from sea level to 920 meters (3,000 ft)
(Corkran and Thomas 1996).
R. aurora is a forest dwelling frog that frequents small ponds, quiet pools along
streams, springs, lakes, reservoirs and swamps in sheltered, damp forests (Nussbaum
et al. 1983, Green and Campbell 1984).
R. aurora is dependant on water for breeding while adults are semi-aquatic to
terrestrial (Gomez and Anthony 1996; Kiesecker and Blaustein 1998).
In the state of Washington, R. aurora has been documented in the three following
Physiographic Provinces: Olympic Peninsula and Southwestern Washington, the
Puget Trough, and Western Slopes and Crests Washington Cascades (Corkran and
Thomas 1996).
There are conflicting reports of territoriality among red-legged frogs. While some
authors have never observed territorial behavior in R. aurora others have observed
male exclusion from breeding (Calef 1973, Nussbaum et al. 1983).
R. aurora is typically found sitting on the banks of ponds etc., during the day,
however, when predators approach it jumps into water and may remain there for long
Unpublished Works © 2003, Puget Sound Energy, Inc.
Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
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periods of time (Gregory 1979, Licht 1986). Red-legged frogs are also encountered
along forest trails near damp valley bottoms (Green and Campbell 1984).
Predation is the main cause of mortality of R. aurora in all stages of development.
Predators of adult and larvae R. aurora include; garter snakes, northwestern
salamanders, bullfrogs, roughskin newts, cutthroat trout, great blue herons, belted
kingfishers, red-tailed hawks, marsh hawks, hooded mergansers, great horned owls,
raccoons, red foxes, striped skunks, minks, and feral housecats. Predators of larvae
R. aurora include; giant water bugs, backswimmers, Dytiscid beetles, water
scorpions, and odonate nymphs (Licht 1974).
A study of R. aurora survivorship in British Columbia estimated 5% of eggs laid
reached metamorphosis. After one season 2.5% of individuals survived and survival
from eggs to sexual maturity was less than 1%. Rate of survival in adults was
significantly higher at 69% (Licht 1974).
Although no long-term population studies of R. aurora have been conducted,
observations suggest that numbers are dwindling in areas outside of old-growth
habitat (Blaustein et al. 1995).
R. aurora aurora is neither a state-listed nor a state-candidate for listing, and it is not
a species of concern by priority habitat type in Washington State (WDFW 1997).
Nesting/Reproductive Behavior:
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R. aurora breeds during winter (January to March) in western valleys and coastal
areas of Oregon and Washington. Movement to breeding sites is temperature
dependent, and males are first to arrive at breeding waters. In Corvallis, Oregon,
frogs migrate to breeding areas when air temperatures reach 10° C (50° F) (typically
in January). R. aurora has the lowest known temperature tolerance of any North
American ranid embryo (Licht 1969, 1971, Nussbaum et al. 1983).
Egg masses are often deposited at night near the water surface, attached to the stems
of submerged vegetation (Nussbaum et al. 1983, Belden and Blaustein 2002). Time
of egg-laying is temperature dependent, generally occurring in February and early
March in northwestern Washington, at water temperatures of at least 6° C (43° F)
(Nussbaum et al. 1983).
Hatching time is dependent on temperature; embryos develop faster in warmer water.
In northwestern Washington, embryos reach the gill circulation stage (stage 20 of 21
in embryo development) in about 35 days (Licht 1971).
In the Puget lowlands, red-legged frogs oviposit in early March, and larvae begin
metamorphosis in late July (Adams 1999). Time of metamorphosis and size at
metamorphosis is dependent on environmental conditions and varies throughout its
range (i.e. R. aurora was 28.7 mm [1.1 inches], 20-25 mm [0.8-1.0 inches], and 22
mm [0.9 inches] at metamorphosis in Washington (Brown 1975), Oregon (Storm
1960), and British Columbia (Calef 1973), respectively). Compared with other
ranids, time to metamorphosis is long (Brown 1975).
R. aurora reach sexual maturity in their second year after metamorphosis when
females measure about 60 mm (2.4 inches) snout-to-vent length and males reach 50
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
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mm (2.0 inches) snout-to-vent length. Limited evidence suggests that males and
females breed every year (Nussbaum et al. 1983).
Some males are polygynous within a single season (Nussbaum et al. 1983).
Habitat Requirements:
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The red-legged frog is the most forest-associated anuran in Washington (Corkran and
Thomas 1996).
R. aurora breeds in relatively still waters shaded by overhanging vegetation (Corkran
and Thomas 1996); small, shallow, temporary ponds, large lakes (i.e. Marion Lake in
British Columbia which is a 13 ha [32 ac] permanent lake), in potholes, in the
overflows of rivers and lakes, and in the slow-moving portions of rivers (Nussbaum et
al. 1983). Emergent vegetation that is linear in structure (i.e. willow branches,
cattails, weed branches, grasses) is characteristic of these habitats (Blaustein et al.
1995).
Within Washington State, R. auroras are most abundant in seasonally flooded areas
attached to permanent wetlands and seasonally flooded areas that hold water through
late July (Adams 1999).
Shallow water and emergent vegetation are essential for growth and development as
these parameters result in warmer temperatures and increased algal productivity
(Kiesecker et al. 2001).
Adults appear to favor riparian areas located in mature stands rather than upslope
habitat or younger stands of trees (Aubry and Hall 1991, Gomez and Anthony 1996).
R. aurora is most common at sites with a shallow slope and southerly aspect (Adams
1999).
A study conducted by Aubry and Hall (1991) in southwestern Washington, found R.
aurora to be negatively associated with elevation, slope, talus, and rocky outcrops
and positively associated with all deciduous and broadleaved evergreen trees. R.
aurora was also highly associated with woody debris but not necessarily with stand
age, which may indicate the importance of woody debris for providing hiding cover.
Amphibian richness is associated with hydrology, vegetative diversity and the
presence of exotic fishes. In many areas of the Pacific Northwest human activities
have altered hydrology and are transforming many temporary wetlands that
historically dried up during summer into wetlands with permanent standing water
year-round. Changes in habitat structure and composition associated with altering
hydrology affect ecosystem productivity, native predator communities, and native
species’ vulnerability to exotic predators and competing species. Although the redlegged frog is most abundant in seasonally flooded areas associated with permanent
standing water, and in temporary wetlands where standing water remains well into the
summer, the loss of shallow emergent marsh may be detrimental. These changes may
also be detrimental for many other aquatic and semi-aquatic species specialized to
temporary wetland environments (Adams 1999).
It is not uncommon for red-legged frogs to move distances greater than 1 km between
riparian breeding sites and upland forests during the post-breeding season. In the
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
south Umpqua basin of southwestern Oregon, a PIT-tagged adult female was found
2.4 km (1.5 mi) from its breeding pond almost 5 months after its initial capture (note:
the author states that this may still not represent the maximum distance traveled
during an active season). PIT-tagged adult males were also recaptured at distances
ranging from 1.1-1.3 km (0.7-0.8 mi) from their breeding pond (Hayes et al. 2001).
Food Resources and Foraging Behavior:
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R. aurora are diurnal foragers, however, they may feed at night during warm weather
(Licht 1986).
R. aurora feed predominantly on land; along river margins and amongst the
surrounding vegetation (Licht 1986).
Both adult and juvenile R. aurora are quite secretive and as a result their feeding
behavior has rarely been documented in the field. Newly transformed red-legged
frogs are relatively conspicuous and are often observed along river banks following
metamorphosis. On warm dry summer days, young R. aurora feed at the water
margin, catching small insects along the banks, in the vegetation and occasionally
swimming a few centimeters into the water to prey on insects on the water surface or
on aquatic plants. During early morning, when moisture collects on vegetation, small
R. aurora can be found feeding in the undergrowth. During or after a rain, R. aurora
will often move further from their water source. R. aurora is often found along the
margins of rainpools catching small prey in and out of the water (Licht 1986).
Prey size increases with age and size of the frog, and includes a wide variety of
insects, arachnids and mollusks (Blaustein et al. 1995).
Red-legged frogs eat beetles, caterpillars, isopods, and other small invertebrates
(Nussbaum et al. 1983).
A red-legged frog was found with a live Columbia Torrent Salamander in its mouth in
September of 2000 in the Stillman Basin, Lewis County, in southwestern
Washington. This marks the first documented case of R. aurora taking vertebrate
prey (Rabinowe et al. 2002).
Responses to Habitat Alteration and Effects of Human Activity:
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Conversion of large, complex wetland areas and temporary ponds to permanent ponds
causes several problems for the R. aurora:
o Permanent ponds lack extensive emergent vegetation essential to R. aurora
survival (Kiesecker et al. 2001).
o Conversion of complex wetlands to permanent ponds has been implicated in
the spread and success of predatory exotics such as bullfrogs and several fish
species all of which require permanent water for over-wintering (Adams 2000;
Kiesecker et al. 2001).
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
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o Permanent ponds increase clumping of the emergent vegetation that is present
resulting in competition for food resources (Kiesecker et al. 2001).
o Shallow water areas are typically of higher temperature and of higher algal
growth, both of which are beneficial to R. aurora development (Kiesecker et
al. 2001).
The following species have been recorded as having significant impact on R. aurora
populations:
o Bull frog; although the occurrence of red-legged frogs in the Puget lowlands is
more closely associated with habitat structure and the presence of exotic fish
than bullfrogs (Adams 1999; Cook and Jennings 2001; Kiesecker and
Blaustein 1998; Keisecker et al. 2001)
o Small mouth bass (Adams 1999; Kiesecker and Blaustein 1998).
o Native newts (Gomez and Anthony 1996)
While sub-lethal, current levels of UV-B light are effecting development of R. aurora
as stratospheric ozone depletion has lead to increased ambient UVB (Belden and
Blaustein 2002).
Acidification of lakes and ponds decreases amounts of dissolved organic carbons in
the water resulting in increased water column penetration by UV-B (Belden and
Blaustein 2002).
Under laboratory conditions, R. aurora tadpoles exposed to relatively high
concentrations of the herbicide Diuron (>7.6 mg/L for 14 days) experienced delayed
hindlimb bud and forelimb development. Although field studies are needed to
determine the effects of Diuron on amphibians following field applications, delays in
R. aurora development could reduce annual survivorship, should their tadpole habitat
dry up before the completion of metamorphosis. Furthermore, delays in larval
development may put R. aurora out of synchronization with available food sources
(Schuytema and Nebeker 1998).
Studies Conducted in the Baker River Watershed:
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The National Park Service’s, Natural Resource Preservation Program conducted an
amphibian inventory of the North Cascades National Park Service Complex from
1989-2002. All surveys were conducted outside of the Baker River Project area
(Holmes and Glesne 1999).
o During the 1993-1994 survey seasons, pitfall traps, installed in Park Slough
near Newhalem, captured red-legged frogs.
o In 1996 red-legged frogs were observed during lake/pond surveys of the Big
Beaver Watershed.
o In 1998 a total of 19 streams and 72 lakes and ponds were sampled in the
Thunder and Bridge Creek watersheds. The closest survey site (identified as
LS-17) to the PSE project area was located approximately 1 km (0.6 mi) from
Baker Lake on the north side of Bacon Peak, in the Noisy creek watershed.
Sampling of lake/pond habitats for amphibians was done using two methods:
shoreline search (visual encounter), and funnel trapping with collapsible nylon
Unpublished Works © 2003, Puget Sound Energy, Inc.
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
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mesh minnow traps. Streams were sampled in a one meter wide belt transect;
ten belt transects one meter wide were sampled in each 100 m (328 ft) stream
reach. Each one meter wide belt transect was visually inspected. A kick net
was then was placed in the stream and all substrate upstream within one meter
of the net was picked up and examined. A pond (BD-02-01) near State Route
20 was the only site that Red-legged frogs were found in 1998 (Holmes and
Glesne 1999).
The Washington Department of Fish and Wildlife, Priority Habitat and Species
database contains 4 records of red-legged frogs in the Baker River drainage from
1900 to 1992. The date, observer, and State Plan XY location of each observation is
available. The database also includes the life-history stage of each observed R. aurora
(i.e., adult, juvenile, or egg mass). Survey methods are not included. This data is
available
from
WDFW
GIS
programmer
Lori
Guggenmos
www.wa.gov/wdfw/hab/phspage.htm.
Hamer Environmental conducted amphibian surveys in 2001-2002 in the reservoir
fluctuation zones of the Baker River Project area. Sample areas were located using
orthoquads and habitat cover maps. Visual encounter surveys, dip-netting, stream
surveys, and funnel trapping were all used to locate amphibians in their various stages
of development. A total of 28 red-legged frogs (8 adult/juveniles, 3 tadpoles, and 17
egg masses) were encountered during the three survey seasons (summer/fall 2001,
spring 2002). The unpublished report contains more detailed information on the
survey methods used, total numbers of red-legged frogs captured during each survey
season, and a habitat description of each observed individual (Martin and Kruger
2002).
Hamer Environmental conducted Oregon spotted frog surveys in the summer of 2001.
Don Gay, a wildlife biologist at Mt. Baker Snoqualmie National Forest, and field
biologists from Hamer Environmental identified all lakes and ponds within the Baker
River watershed. Survey sites were then selected from the recently compiled list of
lakes and ponds, based on their potential as optimal habitat for the Oregon spotted
frog. All the sites surveyed were less than 2,000 ft (610 m) in elevation. A total of 22
sites were sampled within the Baker River watershed. Surveys were conducted on
warm sunny days, between 15 June and 15 September 2001. Two visits were
conducted with 21 days between visits. Survey methods consisted of visual
encounter, dip-netting and funnel trapping. Oregon Spotted frogs were not observed
during either survey period, however, a total of 10 red-legged frogs (7 adult /
juvenile, and 3 tadpoles) were encountered during the 2 survey visits (Kruger 2002).
Mount Baker Snoqualmie National Forest has GIS covers available for the red-legged
frog. This data is available from Puget Sound Energy, Tony Fuchs,
[email protected].
Unpublished Works © 2003, Puget Sound Energy, Inc.
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
Literature Cited:
Adams, M. J. 1999. Correlated Factors in Amphibian Decline: Exotic Species and
Habitat Change in Western Washington. Journal of Wildlife Management 63(4):11621171.
Adams, M.J. 2000. Pond permanence and the effects of exotic vertebrates on Anurans.
Ecological Applications 10(2):559-568.
Aubry, K.B., and P.A. Hall. 1991. Terrestrial amphibian communities in the southern
Washington Cascade Range. Pages 327-338 in L.F. Ruggiero, K.B. Aubry, A.B. Carey,
and M.H. Huff, technical coordinators. Wildlife and vegetation of unmanaged Douglasfir forests. U.S. Forest Service General Technical Report PNW-GTR-285.
Belden, L.K., and A.R.Blaustein. 2002. Exposure of red-legged frog embryos to
ambient UV-B radiation in the field negatively affects larval growth and development.
Oecologia 130:551-554.
Blaustein, A.R., J.J. Beatty, D.H. Olson, and R.M. Storm. 1995. Red-legged frog (Rana
aurora). Pages 44-48 in The Biology of Amphibians and Reptiles in Old-Growth Forests
in the Pacific Northwest. General Technical Report PNW-GTR-337. U.S. Forest Service,
Pacific Northwest Research Station.
Brown, H.A. 1975. Reproduction and development of the red-legged frog, Rana aurora
in northwestern Washington. Northwest Science 49(4): 241-250.
Calef, G.W. 1973. Spatial distribution and “effective” breeding population of red-legged
frogs (Rana aurora) in Marion Lake, British Columbia. Canadian Field-Naturalist
87:279-284.
Cook, D., and M.R. Jennings. 2001. Rana aurora draytonii; Predation. Herpetological
Review 32(2):182-183.
Corkran, C.C., and C. Thomas. 1996. Amphibians of Oregon, Washington and British
Columbia. Lone Pine Publishing. Redmond, Washington.
Gomez, D.M., and R.G. Anthony. 1996. Amphibian and reptile abundance in riparian
and upslope areas of five forest types in western Oregon. Northwest Science 70( 2):109117.
Green, D.M., and R.W. Campbell. 1984. Red-legged frog. Pages 77-79 in The
Amphibians of British Columbia. British Columbia Provincial Museum; Handbook No.
45.
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
Gregory, P.T. 1979. Predator avoidance, behavior of the red-legged frog (Rana aurora).
Herpetologica 35(2):175-184.
Hayes, M.P., and M.M. Miyamoto. 1984. Biochemical, behavioral and body size
differences between Rana aurora and R. a. draytonii. Copeia 1984(4):1018-1022.
__________., C.A. Pearl, and C.J. Rombough. 2001. Rana aurora aurora; movement.
Herpetological Review 32(1):35-36.
Holmes, R.E., and R.S. Glesne. 1999. NOCA NRPP Amphibian inventory North
Cascades National Park Service Complex. North Cascades National Park Service
Complex, 2105 State Route 20, Sedro-Woolley, WA 98284-9314. 84pp.
Kiesecher, J.M., and A.R. Blaustein. 1998. Effects of introduced bullfrogs and
smallmouth bass on microhabitat use, growth and survival of native red-legged frogs
(Rana aurora). Conservation Biology 12(4):776-787.
_____________., A.R. Blaustein, and C.L. Miller. 2001. Potential mechanisms
underlying the displacement of native red-legged frogs. Ecology 82(7):1964-1970.
Kruger, L. 2002. Oregon spotted frog inventory of the Baker River Project. Relicense
Study No. T11. Unpublished Work. Puget Sound Energy, Inc. Tony Fuchs
Licht, L.E. 1969. Comparative breeding behavior of the red-legged frog (Rana aurora
aurora) and the western spotted frog (Rana pretiosa pretiosa) in southwestern British
Columbia. Canadian Journal of Zoology 47:1287-1299.
_________. 1971. Breeding habits and embryonic thermal requirements of the frogs,
Rana aurora aurora and Rana pretiosa pretiosa, in the Pacific Northwest. Ecology
52(1):116-124.
_________. 1974. Survival of embryos tadpoles, and adults of the frogs, Rana aurora
aurora and Rana pretiosa pretiosa sympatric in southwestern British Columbia.
Canadian Journal of Zoology 52:613-627.
_________. 1986. Food and feeding behavior of sympatric red-legged frogs, Rana
aurora, and spotted frogs, Rana pretiosa, in southwestern British Columbia. Canadian
Field-Naturalist 100:22-31.
Martin, R., and Kruger, L. 2002. Amphibian surveys in the reservoir fluctuation zones of
the Baker Lake Project area T17. Unpublished Work © Puget Sound Energy, Inc. Tony
Fuchs.
Nussbaum, R.A., E.D. Brodie, Jr., and R.M. Storm. 1983. Red-legged frog Rana aurora
Baird and Girard. Pages 157-161 in Amphibians and Reptiles of the Pacific Northwest.
University Press of Idaho.
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
Rabinowe, J.H., J.T. Serra, M.P. Hayes, and T. Quinn. 2002. Rana aurora aurora
(northern red-legged frog); diet. Herpetological Review 33(2):128.
Schuytema, G.S., and A.V. Nebeker. 1998. Comparative toxicity of Diuron on survival
and growth of Pacific treefrog, bullfrog, red-legged frog, and African clawed frog
embryos and tadpoles. Archives of Environmental Contamination and Toxicology
34:370-376.
Storm, R.M. 1960. Notes on the breeding biology of the red-legged frog (Rana aurora
aurora). Herpetologica 16:251-258.
Washington Department of Fish and Wildlife. 1997. Washington gap analysis.
Washington Cooperative Fish and Wildlife Research Unit, University of Washington,
Seattle, WA, USA. Available online at ftp://198.187.3.50/pub/gapdata/herps/gifs/raau.gif.
January 2003.
Literature Review:
Aubry, K.B. 2000. Amphibians in managed, second-growth Douglas-fir forests. Journal
of Wildlife Management 64(4):1041-1052.
Blaustein, A.R., and R.K. O’Hara. 1986. An investigation of kin recognition in redlegged frog (Rana aurora) tadpoles. Journal of Zoology, London 209:347-353.
____________., P.D. Hoffman, J.M. Kiesecker, and J.B. Hays. 1996. DNA repair
activity and resistance to solar UV-B radiation in eggs of the red-legged frog.
Conservation Biology 10(5):1398-1402.
Chivers, D.P., J.M. Kiesecker, E.L. Wildy, L.K. Belden, L.B. Kats, and A.R. Blaustein.
1999. Avoidance response of post-metamorphic Anurans to cues of injured conspecifics
and predators. Journal of Herpetology 33(3):472-476.
Davidson, C., B.H. Shaffer, and M.R. Jennings. 2001. Declines of the California redlegged frog: climate, UV-B, habitat and pesticides hypotheses. Ecological Applications
11(2):464-479.
Dumas, P.C. 1966. Studies of the Rana species complex in the Pacific Northwest. Copeia
1:60-74.
Fellers, G.M., A.E. Launer, G. Rathbun, S. Bobzien, J. Alvarez, D. Sterner, R.B.
Seymour, and M. Westphal. 2001. Overwintering tadpoles in the California red-legged
frog (Rana aurora draytonii). Herpetological Review 32(3):156-157.
Unpublished Works © 2003, Puget Sound Energy, Inc.
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
Kiesecker, J.M., and A.R. Blaustein. 1997. Population differences in responses of redlegged frogs (Rana aurora) to introduced bullfrogs. Ecology 78(6):1752-1760.
__________., D.P. Chivers, A. Marco, C. Quilchanos, M.T. Anderson, and A.R.
Blaustein. 1999. Identification of disturbance signal in larval red-legged frogs, Rana
aurora. Animal Behaviour 57:1295-1300.
Lawler, S. P., D. Dritz, T. Strange, and M. Holyoak. 1999. Effects of introduced
mosquitofish and bullfrogs on the threatened California red-legged frog. Conservation
Biology 13(3):613-622.
Rathbun, G.B., N.J. Scott, Jr., and T.G. Murphey. 1997. Rana aurora draytonii
(California red-legged frog); Behavior. Herpetological Review 28(2):85-86.
___________. 1998. Rana aurora draytonii; egg predation. Herpetological Review
29(3):165.
___________., and J. Schneider. 2001. Translocation of California red-legged frogs
(Rana aurora draytonii). Wildlife Society Bulletin 29(4):1300-1303.
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Baker River Project Terrestrial Working Group Analysis Species: Final Report 2/21/03
Figure 1. Core and peripheral habitat zones for the red-legged frog in Washington State
(Washington Gap Analysis Project 1997).
Unpublished Works © 2003, Puget Sound Energy, Inc.
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