Background: 
Le Conte’s thrashers are a state and federal species of concern due to habitat destruction of an already disjunct range.  The distribution of this thrasher extends from southern Nevada and Utah through California and Arizona into northern Mexico in extremely arid and sparsely vegetated landscapes.  In Arizona, the Barry M. Goldwater Range contains the majority of habitat for Le Conte’s thrashers within its extensive creosote flats.  This cryptic species can be difficult to detect as it typically forages elusively on the ground beneath shrubs and trees unless enticed to vocalize (e.g., by other territorial males or by surveyors implementing broadcast calls) when they usually select a higher perch to respond.

Location:
The study area is located in southwestern Arizona on the Barry M. Goldwater Range in the San Cristobal Valley near Dateland and south of Interstate 8.

Approach:
We implemented broadcast surveys at points spaced 400 meters, along transects projecting out from a randomly generated plot.   Thirty plots were randomly generated that then consisted of 20 survey stations for a total of 600 points where this species was surveyed.  Broadcast surveys were employed to maximize detectability.

Vegetation measurements will ultimately be collected within a 15-meter diameter circular plot centered at each confirmed nest location and each perch (with a GPS) from which Le Conte’s thrashers are first detected vocalizing during each survey.  Parameters to be collected within each plot include: type of perch used, perch height, and crown diameter.  Additionally, along six 15 meter transects radiating from plot center we will employ the point-intercept method to determine percent ground cover in five categories (bare ground, litter, dead woody debris, live vegetation or rock).  Vertical height indices for plant species will be determined with a Robel pole at the point-intercepts along each transect.  The average height and mean crown diameters will be calculated for all tree species within the plot.  Additionally, we will take four photos at each cardinal direction shooting from the plot boundary to the center of the plot (i.e. the nest site or vocalizing perch).

Benefits:
This research will provide baseline information on Le Conte’s thrasher territories and will be especially useful for BMGR managers when implementing training maneuvers. 

For more information contact:
Scott Blackman, Arizona Game and Fish Department
5000 W. Carefree Highway Phoenix, AZ 85086-5000
Phone: (520) 742-1911  Email: sblackman@azgfd.gov

Michael Ingraldi, Arizona Game and Fish Department
5000 W. Carefree Highway Phoenix, AZ 85086-5000
Phone: (928) 532-5625 Email: mingraldi@frontiernet.net