Kansas wildlife researchers find low eye-worm infection rates in quail and pheasants, urge habitat focus

Jeff Prendergast, a staff presenter, told the Kansas Wildlife and Parks Commission that samples collected from hunter-harvested birds indicate relatively low infection rates of Oxyspirura (commonly called “eye worms”) across Kansas. The department collected and lab-processed hundreds of bobwhite and pheasant heads in 2018 and found 4.2% positive among 283 bobwhites and 12.5% positive among 213 pheasants, with most infected birds carrying only a single parasite, Prendergast said.

Prendergast said the eye worm lifecycle involves eggs passed in feces, insect intermediate hosts and then ingestion by birds; the species detected is an avian specialist and “humans aren’t at risk,” he told commissioners. He said the researchers found an even geographic distribution of low-intensity infections, and only one bobwhite had a very high intensity (28 worms).

Interest in treating eye-worm infections increased after a Texas research team obtained U.S. Food and Drug Administration approval for a medicated feed that uses fenbendazole. Prendergast said the manufacturer recommends placing medicated feed in dedicated feeders, with a 21-day treatment period and about one feeder per 200 acres, and two treatment periods per year (spring and fall). But he cautioned that there is no strong evidence that treating eye worms increases individual fitness or produces population-level gains for wild game bird populations.

Prendergast urged caution about non-target exposure and behavioral effects. “If you think you can put feed out and come up with the answer, people tend to be more likely to do that than the work it takes to create and maintain habitat over the long term,” he said. He noted research from other regions that shows concentrating birds at feeders can raise predation risk and that medicated feed may break down quickly in the environment, creating potential exposure of rodents or other animals.

Commissioners and staff asked for the slides and lab details; Prendergast said he would provide them for the public briefing and minutes. Department staff recommended continuing monitoring and prioritizing ‘‘Habitat First’’ investments — habitat work and landscape-scale conservation that produce multi-year benefits — rather than relying on feeder-based treatments as a primary management tool.

Prendergast and commissioners said the department will keep the sample baseline and revisit the question as further research and monitoring data become available. The commission did not take a vote on a policy change; the presentation was informational.

The department said slides and the briefing will be posted with the meeting minutes.