Northern Leopard Frog Recovery Program Year 6 (2004)
The northern leopard frog (Rana pipiens) was once a common amphibian found throughout
central and southern Alberta. During the late 1970s, the leopard frog experienced a dramatic
decline in distribution and numbers over much of its historic range in Alberta. Today, the
leopard frog is designated as Threatened under Alberta’s Wildlife Act and is currently extirpated
from the upper Red Deer River and the North Saskatchewan River drainage (Wagner 1997,
Kendell 2002b, Alberta Sustainable Resource Development 2003).
The leopard frog has demonstrated little ability to naturally disperse back into historic parts of its
range. As a result, in 1998, the Alberta Fish and Wildlife Division began to explore the
feasibility of reintroducing leopard frogs into formerly occupied habitats in the upper Red Deer
River and North Saskatchewan River drainage basins. With the information gathered, the Alberta
Conservation Association initiated a pilot reintroduction project in 1999 at the Raven Brood
Trout Station near Caroline, Alberta. The project involves the captive rearing of leopard frogs
from egg stage of development to metamorphosed frog, in two man-made outdoor ponds at the
The primary objective of the project is to re-establish leopard frogs in the upper Red Deer River
and North Saskatchewan River drainage. Through the efforts of the northern leopard frog
reintroduction program, over 13,000 leopard frogs have been captive-reared at the Raven Brood
Trout Station and released into habitats within the historical range of the species. Of these
13,000 leopard frogs, approximately 9,000 frogs have been released into the upper headwaters of
the Red Deer River near Caroline, since the projects inception in 1999. Over a three-year period
beginning in 2001, 2845 frogs have been released at a site along the North Saskatchewan River
near Rocky Mountain House and over a two-year period beginning in 2002, 1310 frogs have
been released at a Ducks Unlimited property, near Red Deer.
All captive reared leopard frogs were marked with a Visual Implant Elastomer (VIE) tag,
providing an externally visible internal identification mark. This tagging system allowed
researchers to better assess the survival success at each release site and to monitor the dispersal
of released frogs.
Confirmed frog observations each year between 2001 and 2004, as well as evidence of breeding
activity in 2002, show some evidence of the preliminary success of the project at the Caroline
release site. With the exception of two unconfirmed leopard frog observations in 2002 at the
North Saskatchewan River release site, no other observations have been documented from that
site or the Ducks Unlimited property despite monitoring efforts.