Pleistocene and ecological effects on continental-scale genetic differential in the bobcat (Lynx rufus), 2012
Bobcats are one of the most common and broadly distributed species in North America, thriving in a wide range of environments. From 1994 to 2011, 1,700 individuals were sampled for genetic diversity across the entire USA. Ecoregion accounted for the largest portion of genetic variation, followed closely by summer precipitation. Longitude, especially along the Great Plains in the central U.S. showed a pattern of isolation by distance, but not latitude. Distinct patterns to species were observed in eastern, central, and western areas. The Great Lakes region and New England has a signature of reduced genetic diversity, as does the Oregon-Washington bobcat population.

Habitat Modeling Used to Predict Relative Abundance of Bobcats in Iowa, 2011

Bow hunter observation between the years 2004 through 2009 of bobcats were combined with remotely-sensed data to build models describing habitat and relative abundance in the agricultural landscape of Iowa. Coyotes were reported every year in every county, but no bobcats were observed in 34 counties during these years. Those counties may have had forest patches along streams and rivers, but there was no transitional grassland to surrounding row cop agriculture. The research demonstrates that maintaining a diverse landscape of grassland and forested perennial habitat in the corn belt could not only enable the continued recolonization of bobcats in the region, but likely will also benefit other wide-ranging wildlife species.

Fall and Winter Food Habits of Bobcats (Lynx rufus) in Iowa, 2007

The stomach contents of 100 bobcat carcasses (half male and half female) collected in southern Iowa between 2002 and 2006 were examined to determine their food habits. Sixty percent of stomachs contained cottontail rabbits, 20 percent contained mice and voles, and 15 percent contained fox squirrels. The study was not conclusive of frequency of predation by bobcats on nesting birds, due to the time of year the bobcats were collected.

Space Use and Habitat Selection by Bobcats in the Fragmented Landscape of South-Central Iowa, 2007
With enrollment into the Conservation Reserve Program developing about the same time bobcat sightings grew, there was interest in learning the space use of bobcats and the importance of habitat type to bobcat expansion in Iowa. Bobcats were radio-collared from March 2003 to March 27 2006 to track their locations. Females' home range was about one-third of males during the April through Sept. rearing season. Forest ranked as the most important habitat for males and females, with grassland and CRP ranking second and third. Row crop land was not used.

Habitat section and demography of bobcats (Lynx rufus) in Iowa, 2006

Master's thesis of Stephanie Ann Koehler, who assisted in the research above. Conclusions from findings suggest that in more fragmented landscapes, bobcats use more area, and used less in landscapes with less fragmentation. The development of CRP does not appear to be important to the growth of the bobcat population in Iowa. Landscape characteristics appear to be influenced most by availability of preferred prey, quality of escape cover (from predators such as coyotes) and lack of human disturbance. A threshold of density of bobcats is likely to occur based on available forest and grassland habitat connections, and the population is likely to decrease as landscapes become more fragmented by agriculture.

Spring Spotlight Survey

The Spring Spotlight Survey is an annual survey conducted by the Iowa DNR to monitor the population trends of deer, raccoon, and other select furbearers. Between mid-March and mid-April, DNR staff drive two rural routes across each county at night and document the number of individuals of each species and their locations observed by spotlight. This survey was initiated in 1978 along select forested habitats to monitor raccoon and deer populations and redesigned in 2006 to allow for statewide coverage of other habitats and species.

The primary objectives for this survey are to:

  • develop a long-term database for monitoring the population trends of deer, raccoon, and other select furbearer species; and
  • develop estimates of deer density across the state.

Spotlight surveys have been used by biologists nationwide since the mid-1900s and are effective for monitoring population trends, determining the distribution of species, identifying habitat use, and predicting disease outbreaks.

Spring Spotlight Survey Results, 2017