Three species of frog have been observed at the
Reserve; two of these are native, while the third has been introduced
to California. Additionally, foothill yellow-legged frogs (Rana
boylii) are known to occur near Quail Ridge, but the lack of
suitable habitat (permanent streams) makes it unlikely that this
species will be found on the Reserve.
Western toad, Bufo boreas (Bufonidae
Family) – Western toads occasionally are seen around the south
end of the Reserve, usually at night or under cover objects. These
medium-sized (5-13 cm SVL) brown and tan frogs with bumpy skin are
not likely to be confused with the other frogs of the Reserve. Although
adult toads have been observed in the drying mud of Decker Pond
in May, they have not yet been observed to breed on the Reserve,
despite careful monitoring of the ponds since 2000.
treefrog, Hyla regilla (Hylidae Family) –
The most abundant frog of the Reserve. Males can be heard calling
any month of the year, although large breeding aggregations begin
in late December or early January, and continue through May. These
small frogs (2-5 cm SVL) are readily recognized by the toepads and
the dark stripe behind the eye. The dorsal coloration and pattern
is highly variable, ranging from bright green to a tan or gray coloration,
and can change within a few minutes. Males have multiple types of
calls that they use to attract females and communicate with other
males. The most common advertisement call is a loud ‘kreeck-eckk’.
They breed at all four ponds on the Reserve, but they do not appear
to breed in the ephemeral streams. Tadpoles metamorphose into little
froglets between May and July, and they usually reach maturity in
one (males) or one to two (females) years. Some adults will live
to breed for several years. Despite their small size, these frogs
are very mobile, and can be found far from the breeding ponds. The
Quail Ridge Reserve is currently the site of an ongoing study on
demography, movement, and local adaptation in Pacific treefrogs.
For more information see Mike Benard's
Rana catesbeiana (Ranidae Family) – Bullfrogs are
nonative and breed in the reservoir surrounding the Reserve. They
can be recognized from their large size (9-20 cm SVL), large tympanum
(eardrum), strongly webbed feet, smooth, olive to green dorsal color,
and often a mottled brown and white belly. Every year a few subadult
bullfrogs move into Decker Pond. In 2004, an adult male was able
to make it into Fordyce Pond – a mile away from the reservoir.
Diet analysis has found bullfrogs will eat nearly any animal small
enough to swallow, from a host of insects, to other frogs, to snakes,
small mammals, and birds. They are an important threat to red-legged
frogs (Rana aurora) in the foothills of the Sierra Nevada.
Bullfrogs are potentially so damaging that they should be eliminated
Photo Credits: Title, Treefrog, Toad,
and other Treefrog (Mike Benard), Bullfrog (Alan Resetar). For more
pictures see: http://elib.cs.berkeley.edu/photos/fauna/