EFFECTS OF PRESCRIBED FIRE ON SONGBIRD USE OF RESTORED PRAIRIE AND OLD FIELD HABITATS

Jeffrey Port, Bethel University, Department of Biology

Periodic fire has long been recognized as a key component of the North American grassland ecosystem. The importance of fire in suppressing woody growth is well documented and its use to control invasive species is a commonly practiced management tool. During the summers of 2003-2005, data was gathered to document the impacts of a controlled burn on insect, small mammal and bird populations utilizing a 21 acre prairie restored with 3 distinct field types. Plots consisted of either a high diversity seed mix (60 + species of grasses and forbs), a low diversity seed mix (3-4 species), or not planted at all (abandoned farm field). The entire site was burned in April 2004 and data on small mammal and bird populations immediately post-burn was collected during the summer of 2004. Data collected during 2003 and 2005 comprise non-burn years and provided the opportunity to monitor the insect, avian and small mammal populations one year pre- and post-burn and directly observe and document the affects of a managed burn on these taxa. Data from adult songbird censuses and nest searches suggest the most frequently encountered resident species (Clay-colored sparrow (Spizella pallida), Song Sparrow (Melospiza melodia), and Sedge Wrens (Cistothorus platensis)) left the study area nearly completely as a result of the burn. Within the heaviest utilized areas, adult census numbers for all species using the high diversity plots dropped significantly between 2003 (n = 6 census dates; mean = 10.03 individuals) and 2004 (n = 6 census dates; mean = 3.54) and increased again in 2005 (n = 7 census dates; mean = 9.75). The number of nest attempts within the entire study site were also similar between 2003 (n=24) and 2005 (n=33) with significantly fewer attempts in 2004 (n=2).