Results of analyzed Mexican spotted owl pellets collected from the Jemez Mountains: 1997 Pellets and Pellets previously analyzed by Reichenbacher and duncan in 1992

DeRosier, Suzanne

Part I. 1997 Pellets This report is a continuation of work started in Methodology and results of analyzed pellets by Mexican spotted owls in the Jemez Mountains (1997) by S. M .. DeRosier. The methodology outlined in the 1997 report is being followed for this analysis, any changes are noted and explained. A total of 709 bags of regurgitated Mexican spotted owl pellets were analyzed. The pellets were collected in 1997 by Terry Johnson from the Jemez Mountains in New Mexico. Each bag contained one pellet sample. A pellet sample consisted of one of the following: A whole pellet, a pellet fragment, loose bones, or a combination of the three. Approximately 487. 5 pellets were analyzed with pellet size estimated to the nearest 0.25 pellet and loose bones recorded as 0.00 pellet. A pellet equivalent number was estimated to the nearest 0.25 pellet for those samples with loose bones. The pellet number equals the pellet equivalent number for those samples with no loose bones. A pellet equivalent total for all samples was 616.25 pellets. A total of 1,742 prey items have been identified. The contents of 1997 pellet report include (1) an updated description of the pellet remains form, (2) list of acronyms used in this study [this cumulative list was updated when new species were found this year, but species found in previous years were not deleted, there fore not all species listed were identified this study year], (3) the results of the study using a modified spreadsheet format developed by Reichenbacher and Duncan (1992), and ( 4) the database that is contained on a 3. 5 computer disk. Part II. Reichenbacher and Duncan (1992) Reanalyzed Prey Remains. Reichenbacher and Duncan analyzed 439 bags of pellets collected from Jemez Mountains Field Station from 1982 - 1990. The methods and results of that study are reported in Reichenbacher, F. W. and R. B. Duncan (1992). Diet of Mexican spotted owls on National Forest system lands in Arizona and New Mexico. The prey items from that analysis had been retained and stored in sorted bags with the exception of some prey removed for reference collections and some missing prey items. The bags contained skeletal remains and a label. All fur and debris had been removed. The Reichenbacher and Duncan analysis sorted the prey items by skeletal groups (i.e. skull, leg bones, misc. parts) and not by individual skeletal parts. This study reanalyzed the already dissected bags of pellets and recorded the results on data forms as described by in DeRosier 1997 and updated in this report. The results of this new analysis were recorded in the same database as the 1997 pellets. The results were not entered into a new spreadsheet.