2019 Breeding Bird Survey Study at the Eagle Valley Nature Preserve, Grant County, Wisconsin

Casper, Gary; McKay, Kelly; Mossman, Michael; Rutherford, Ryne

We conducted research comparing breeding bird point counts to acoustic survey methodology in hardwood forest habitat. Acoustic monitoring is a cost effective and rigorous technique especially suited to obtaining large sample sizes, and to monitoring remote locations that are difficult to visit repeatedly. Objectives were to a) compare species lists for each site by each method; b) compare differences in species detection rates by method; c) calculate the number of surveys necessary for achieving 95% confidence in detection for species by each method; and d) make recommendations for a long-term monitoring program for breeding birds to better inform habitat management. Our study quantified detection rates for 5 and 10 minute duration early morning point counts and acoustic surveys, identified a suite of forest associated Focal Species with high detection rates most suitable for monitoring, and quantified effort needed for detecting rarer species at statistically significant rates. We recommend a long term monitoring program utilizing acoustics for annual occupancy monitoring, supplemented with periodic point count/atlassing surveys that collect evidence of reproduction. We identify survey effort levels returning detection rates high enough to avoid the need for modeling occupancy trends for each species, which allows for using annual data directly at 95% confidence levels, thereby avoiding uncertainty of avian use of managed habitats. Follow up research is recommended to further explore how time-of-day affects detection rates, and to quantify acoustic detection rates for night calling and crepuscular species.Land management actions are driven by complex social and physical factors and desires. In this study weprovide the means to establish a rigorous monitoring program at relatively low cost for forest associated breeding birds, which can provide easily interpreted data for direct habitat management feedback loops. Birds are relatively easy to conserve and recover given their high mobility and prompt utilization of new habitats, i.e., “if you build it they will come”. This paradigm however is not true for many other species groups of importance at the Eagle Valley Nature Preserve, in particular rare plants and reptiles(and possibly insects), where preservation and enhancement of existing populations, and repatriation of extirpated species, often require direct targeted management actions and may have priority over more