Justification: Monitoring of bird diversity and phenology can be done using a variety of methods, each with its own set of biases (see Bart & Earnst 2002, Thompson 2002). In addition to recording birds as part of the vertebrate monitoring component, using motion sensor cameras: we decided not to use point counts for three reasons. First, students, community members and interested researchers would require extensive training to learn the calls of the full diversity of birds. Second, extensive effort and training would be required to standardize data collection among observers in an effort to limit observer bias (lack of consistency among surveyors). Third, point counts are biased towards birds that are breeding (and therefore singing) but often miss the non-breeding bird residents and the migrants.

Monitoring Protocol: Bird surveys will be conducted along a census trail which should run through all different habitat types. Different portions of the census trail will be broken into transects based on different habitat types and be clearly demarcated. The surveyor will identify observation points in each transect. The time at each observation point will be recorded as will all bird species observed. This approach should provide a good record of the bird species present annually in each California Sage Scrub (CSS) fragment and habitat preferences of different bird species, but will not provide a record of the relative abundances of the different species.

Data from each participating institution should be uploaded to eBird, a public repository of bird records.

[Link to Bernard Field Station Data 2001 to Present coming soon!]

References

  • Bart, J., & S. Earnst 2002. Double sampling to estimate density and population trends in birds. The Auk 119: 35-45.
  • Thompson, W.L. 2002. Towards reliable bird surveys: accounting for individuals present but not detected. The Auk 119: 18-25.