Blake, John G.Hanowski, JoAnn MNiemi, Gerald J2014-04-022017-04-142014-04-022017-04-141988https://hdl.handle.net/11299/187181ANNUAL REPORT: 1987; SUBCONTRACT NUMBER: EO6549-84-011This investigation was designed to isolate effects of electromagnetic fields produced by ELF antenna systems on bird species breeding in or migrating through Wisconsin and Michigan. Specifically, we seek to determine if bird species richness and abundance differ between areas that are close to the antenna and those that are far enough away to be unaffected by the antenna. We are pursuing this question at both the community and species level. Characteristics examined include total species richness and abundance, abundances of common bird species, and abundances of birds within selected guilds (based on habitat, diet, migration strategy, and nesting behavior). This report summarizes 1987 research activities for studies to identify potential effects of ELF electromagnetic fields on bird species and communities in Wisconsin and Michigan. Our monitoring program included bird censuses over a five month period from May to September. In addition, we completed a detailed habitat assessment of all control and treatment segments in Wisconsin that was initiated in 1986. These data will allow us to pair control and treatment segments on the basis of habitat, thereby enabling us to assess effects of the ELF antenna, even though there are no pre-impact data available from Wisconsin. The Michigan transmitter operated intermittently at low levels during 1987. We are therefore considering 1987 a transitional year in terms of EM exposures. Principal components (PCA) and Bray-Curtis analyses of vegetation on Wisconsin segments revealed differences between treatment and control segments. Qualitative assessments of habitat types in Michigan also revealed differences between segment types. The most X important difference in relation to birds relates to distribution of coniferous and deciduous habitats. Treatment segments support more coniferous and lowland habitats than do control areas in both states. Logging affected the vegetation on four treatment segments in Michigan and four treatment and one control segment in Wisconsin. In Michigan, clear-cutting along several treatment segments resulted in a significant difference between treatment and control segments in the amount of early successional habitat, with more now present on treatment sites. Logging was less severe in Wisconsin but did result in significant changes in some habitat variables for the affected segments. We omitted all segments affected by logging in our between year comparisons of bird communities. Five segments sampled for vegetation in Wisconsin in 1986 were resampled in 1987. Between year differences were noted for seven variables, especially ground cover, canopy cover, and overall height of the vegetation. Measurement of these variables involves some qualitative estimations and between year differences may be due to sampling effects. These variables were not included in PCA. Bird abundance and species diversity were highest in June and July in Michigan and in May and June in Wisconsin. Observations reached a low in September in Michigan but increased from August to September in Wisconsin. Differences between treatment and control segments in total number of individuals and species were not consistent across seasons in either state. Species richness was higher on control than on treatment segments in Michigan in May; no other differences in community level parameters were significant in either state. Considerable annual variation in numbers of individuals and species was noted, particularly in Michigan, where significant year effects occurred in four of five sample periods. Annual differences were not, however, consistent among seasons in Michigan. Particularly abundant species (all seasons included) included the Nashville Warbler, Ovenbird, White-throated Sparrow, Red-eyed Vireo, Black-capped Chickadee, Golden-crowned Kinglet, and Red-breasted Nuthatch. The most abundant species present on treatment and control segments varied among seasons and between states. Among "abundant" species (>1 individual observed/ 500 m segment), seven comparisons (over all seasons) revealed a significant difference between treatment and control segments in Michigan; five indicated a greater abundance on treatment segments. Three comparisons indicated a higher abundance on treatment segments in Wisconsin and two on controls. Twelve comparisons in Michigan and eight in Wisconsin showed significant annual variation in abundance. Twenty-one comparisons of common species (based on prominence values) between treatment and control segments in Michigan and 14 in Wisconsin were significant. Values were higher on control segments in Michigan in all but two cases; 9 of 14 were more abundant on control segments in Wisconsin. Few species were consistently and significantly more abundant on either treatment or control segments among seasons within a year or within seasons between years. Differences between treatment and control segments, particularly in Michigan where the antenna was operated periodically, are most likely due to habitat differences. Species were classified into guilds on the basis of migratory strategy, nest site preference, diet and foraging location, and preferred breeding habitat. Abundances of different guild types on treatment and control segments were compared for June 1985, 1986, and 1987, the primary breeding season. Few significant differences were found between treatment and control segments and most were not consistent among years. Differences were most consistent for habitat categories, suggesting that habitat differences between treatment and control segments may be responsible for many of the observed differences in bird distribution patterns. We repeated tests for differences in abilities of observers to detect birds, for differences in spring arrival times of several different groups of birds, and for potential edge effects on distribution patterns of birds. Few significant differences emerged.enELF communications systemBird speciesElectromagnetic fieldsWisconsinMichiganNatural Resources Research InstituteUniversity of Minnesota DuluthTechnical Report