There is an anecdotal view that bluebirds exist only in the purest environments, and that they are more susceptible to pesticide bioaccumulation than other wildlife. Swallows that feed on insects disturbed by mowers should be better indicators of bioaccumulation. Remove early-season nests after the residents fledge to encourage a second nest in the same nest box. In southern Wisconsin, the first brood of bluebird young will fledge around the end of April. The adult pair, with the assistance of the first brood, will often nest again and raise a second brood.
Younger adults nest later in the year and raise one brood.
Wrens and tree swallows compete for nest sites at this time, and these more aggressive species may evict bluebirds. As a turfgrass diagnostician at the College's O. J. Noer Turfgrass Research and Education Facility, Gaard regularly visits golf courses to discuss management strategies with the superintendents. The O.J. Noer facility, which adjoins University Ridge, joined the Audubon Cooperative Sanctuary Program for Businesses in 1995. The program provides information and guidance to golf-course managers and property owners to help them preserve and enhance wildlife habitat.