Monitoring protocol for otter and bobcat in Iowa


Principal Investigator:

Robert W. Klaver

Student Investigator:

Bridget Nixon (Ph.D.)




January 2016 to May 2020

Funding Source(s):

Iowa Department of Natural Resources

Drake University

Goals and Objectives:

  • Comparing conventional population indices to integrated population modeling (IPM) to determine if IPM provides superior inferences that warrant its use as an otter and bobcat management tool.
  • Performing IPM to provide estimates on otter and bobcat survival, age structure, recruitment, harvest, and population trends in Iowa.
  • Using GIS to develop a river otter habitat suitability map for Iowa based on the number of otters trapped per HUC 12 watersheds as a function of land cover and landscape metrics comparable to the suitability map developed for the bobcats. Validating the habitat suitability map created in item 3.
  • Evaluating the value of current data sources and simulating potential gains by including additional ancillary data for use in managing Iowan furbearers.
  • Publishing a final report and outlining recommendations to the Iowa DNR for future furbearer monitoring.



Pilot surveys of latrine sites were conducted during summer 2016. While latrines were located during these surveys, the consensus of Iowa State and DNR participants was that it was unlikely that the time investment necessary for successful surveys was feasible for inclusion as ancillary data. Related literature was reviewed and compiled, with new publications and additions being added as needed. 663 additional otter teeth were submitted to Matson’s Lab to be aged, bringing samples from each year up to 20 – 25% of that year’s total harvest. The teeth were recovered from previously pulled samples or pulled from jaws which had been frozen. Initial modeling has been started on otter habitat suitability with the aim of presenting a habitat suitability map at the annual Coop meeting. Compiling of bobcat teeth was started from 2007 – 2012.


Future Plans:

Bobcat teeth: Additional bobcat teeth needed to reach 20 – 25% of each year’s harvest will be taken from frozen jaws or previously pulled samples and sent for aging. Previously aged teeth from 2007 – 2015 will be combines with CITES data on gender and collection date and location.

Otter habitat suitability: Landscape and land cover metrics relating to otter presence will be modeled and a map created to evaluate suitability across Iowa. The map will be validated using additional years of otter capture data.

Ancillary data: Options for ancillary data to include in the IPM will be evaluated and appropriate data will be added to an age-at-harvest model.

01/01/2016 to 05/31/2020