Tricolored Blackbird 2017 Statewide Survey Protocol

A statewide survey of all known colony locations is conducted every three years in order to estimate the size of the Tricolored Blackbird population in California and to provide a basis for documenting the statewide population trend. This information is critical to guide conservation efforts and could not be accomplished without the help of a large number of concerned citizens like you. This protocol is provided to standardize the methods used by all participants in the statewide survey.

The goal of the survey is to obtain a count of Tricolored Blackbirds in the state by utilizing a large number of experienced individuals who attempt to visit all historical breeding colony sites and search for new breeding sites. The number of birds is estimated both at breeding colonies and at any aggregations of nonbreeding birds that may be seen.

This comprehensive survey is confined to a 3 day interval early in the breeding season to maximize the number of birds at known, fixed locations so as to maximize the number of birds that may be reliably found and counted and to reduce the possibility of double-counting birds that move between locations. By standardizing our field methods we obtain the most accurate estimate of the statewide population.

TRBL 2017 Statewide Survey Protocol.pdf194.04 KB