Dr. Harper is an avian ecologist with diverse research interests. He is collaborating with Dr. Jeff Frick, an organic chemist at Illinois Wesleyan University (IWU) and a number of IWU students on research projects quantifying and determining patterns of organochlorine (OC) pesticide (e.g., DDT) levels in birds and other wildlife.

One collaborative project with Dr. Brian Peer, an IWU alum at Western Illinois University, involves screening dickcissel (a small, grassland nesting, sparrow-like bird) eggs for levels of OC compounds. Dr. Peer noticed that some dickcissel eggs tend to break easily and OC compounds have been documented as causing eggshell thinning in several species of raptorial birds.

Another collaborative project is with U.S. and Canadian Wildlife officials in determining OC levels in lethally controlled wolves taken from Alaska, Wyoming, Idaho, Montana, Alberta and the Northwest Territories. No recent studies have been conducted on pesticides in wolves from these areas. A previous study conducted at IWU documented that wolves and tree bark from Minnesota contained OCs at levels as high as 5 part per million.