Marsh Bird Surveys

Marsh bird surveys are part of the Monitoring and Research Measures of the Habitat Conservation Plan of the LCR MSCP.  Marsh birds are seldom seen so surveys are conducted in which calls of the marsh birds are played to elicit responses. This method is used nationwide to monitor marsh bird populations.  The species that the LCR MSCP survey for are Yuma clapper rail, California black rail, least bittern, and Virginia rail (Rallus limicola).

Surveys are conducted during March, April and May, part of the breeding season, and start a half hour before dawn and continue for 3 or 4 hours, which is when the birds usually stop calling.  A survey consists of 5 minutes of quietly listening for the marsh birds calling, then playing several calls of each species during 1 minute intervals and listening for their responses.  Each time a bird calls, the species and type of call are identified, the time period is marked down as is the distance and direction from the surveyor.  Because marsh birds do not respond to the played calls every time, the surveys only tell us the minimum number of birds of a given species that are present in the survey area at the time of the survey.  Three surveys are conducted to get a more accurate number of marsh birds present.  Surveys that span years can show population trends and status.

Identifying marsh plants and their composition at sites where we find marsh birds helps with the creation of marshes.  Marsh bird surveys are conducted both before and after the creation of marshes to monitor the LCR MSCP’s progress on creating marsh bird habitat.

For additional information on this project, please refer to Work Task D1: Marsh Bird Surveys (PDF). Find Technical Reports for this Work Task here.

Updated October 14, 2011