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Assessment of Trends in Breeding Bird Communities in Four Midwestern National Park Service Units. Bird Sampling Method – Point Transect Time interval (0 – 3 min., 3 – 5 min., > 5 min.) Record species Record distance Record detection type Record sex / age Record flock size
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Assessment of Trends in Breeding Bird Communities in Four Midwestern National Park Service Units
Bird Sampling Method – Point Transect • Time interval (0 – 3 min., 3 – 5 min., > 5 min.) • Record species • Record distance • Record detection type • Record sex / age • Record flock size • Record if the bird was a flyover
Bird Data Analysis • Identify species with > 60 observations • Calculate Densities using DISTANCE software • Calculate Richness, Evenness, Diversity • Graph metrics for parks with > two years of data • Compared metrics on breeding males with all individuals
Agate Fossil Beds National Monument n = 243 plots sampled n = 60 bird species Individuals / plotPlots occupied Red-wing-blackbird Western meadowlark Western meadowlark Red-winged blackbird Grasshopper sparrow Grasshopper sparrow Lark sparrow Lark sparrow Lark bunting Mourning dove 7 PIF Species of Continental Importance Common Species
Common Species Herbert Hoover National Historic Site n = 18 plots sampled n = 21 bird species Individuals / plotPlots occupied Red-winged blackbird Red-winged blackbird Common yellowthroat Common yellowthroat Dickcissel Dickcissel American goldfinch American goldfinch Common grackle American robin 3 PIF Species of Continental Importance
Population Trends All individuals 2005 2006 Richness 4.11 (1.45) 4.33 (1.73) Evenness 0.92 (0.12) 0.86 (0.16) Diversity 1.23 (0.40) 1.24 (0.49) Males Richness 3.78 (1.56) 4.22 (1.86) Evenness 0.82 (0.32) 0.93 (0.08) Diversity 1.13 (0.53) 1.26 (0.48)
Hopewell Cultural National Historical Park n = 54 plots sampled n = 54 bird species Individuals / plotPlots occupied Red-winged blackbird Red-winged blackbird Dickcissel Eastern meadowlark Grasshopper sparrow Field sparrow Tree swallow Grasshopper sparrow Field sparrow AMRO, NOCA, YBCH 11 PIF Species of Continental Importance Common Species
Population Trends All individuals 2005 2006 Richness 4.96 (1.60) 4.52 (1.70) Evenness 0.84 (0.13) 0.85 (0.22) Diversity 1.31 (0.35) 1.29 (0.49) Males Richness 2.37 (2.04) 4.15 (1.66) Evenness 0.50 (0.46) 0.86 (0.26) Diversity 0.67 (0.65) 1.24 (0.51)
Common Species Tallgrass Prairie National Preserve n = 729 plots sampled n = 94 bird species Individuals / plotPlots occupied Western meadowlark Western meadowlark Grasshopper sparrow Grasshopper sparrow Dickcissel Upland sandpiper Brown-headed cowbird Brown-headed cowbird Upland sandpiper Dickcissel 14 PIF Species of Continental Importance
Conclusions • Distance sampling and analysis is of limited value to us when monitoring trends in breeding bird communities. • Distance sampling and analysis real value is in monitoring trends in the numbers and density of targeted species population. • Also, based on Student T-test, males and all individuals combined produced similar results when measuring trends. • However, all individuals combined have a slightly better measure of variance around their means than males alone making them the better choice for monitoring population trends.