Boreal Toad Monitoring

PI: Brad Lambert

CNHP formed a partnership with the Colorado Division of Wildlife (CDOW) in 1999 to monitor known breeding sites and to survey locations throughout Colorado for new populations of the state endangered boreal toad (Bufo boreas). The data collected have been used by the Boreal Toad Recovery Team to assess the status of the boreal toad in Colorado, and by the U.S. Fish and Wildlife Service to assess the status for potential federal listing as an endangered species. CNHP has continued this work yearly with a contract in place to extend this project through 2012.

In 2008, CNHP monitored 26 known breeding sites in Chaffee, Eagle, and Summit Counties. Monitoring consists of making repeated visits to breeding sites to collect baseline information on high counts and breeding success. In addition, 91 sites throughout Colorado were surveyed for boreal toads. Two new breeding sites were documented, both in Chaffee County.

CNHP also continued a mark-recapture study in the Cottonwood Creek drainage in Chaffee County. The study was set up in 1999 to look at demographic variables in a large metapopulation of boreal toads. Over 1,500 adult toads have been tagged between 1999 and 2008. CNHP is currently analyzing these mark-recapture data to increase understanding of estimated population size, survival, site fidelity, and movement between breeding sites. The data set is also being used for distribution modeling exercises to help guide future survey efforts.


Muths, E., R.D. Scherer, and B.A. Lambert. 2010. Unbiased survival estimates and evidence for skipped breeding opportunities in females. Methods in Ecology and Evolution 1:123-130.

Pilliod, D.S., E. Muths, R.D. Scherer, P.E. Bartlet, P.S. Corn, B.R. Hossack, B.A. Lambert, R. McCaffery, and C. Gaughan. 2010. Effects of amphibian chytrid fungus on individual survival probability in wild boreal toads. Conservation Biology 24(5):1259-1267.

Scherer, R.D., E. Muths, and B.A. Lambert. 2008. Effects of weather on survival in populations of boreal toads in Colorado. Journal of Herpetology 42(3):508-517.

Muths, E., R.D. Scherer, P.S. Corn, and B.A. Lambert. 2006. Estimation of temporary emigration in male toads. Ecology 87(4):1048-1056.