A Survey for the Evening Bat, Nycticeius humeralis, in Wisconsin By: Matt Willey, advisor Dr. Jeff Huebschman

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1 A Survey for the Evening Bat, Nycticeius humeralis, in Wisconsin By: Matt, advisor Dr. Jeff Huebschman Wisconsin is adjacent to the northern geographic limit of the evening bat (Nycticeius humeralis), where it remains undocumented. Its absence in Wisconsin may be due to a lack of sufficient sampling. In summer 2007 we surveyed bats using mist nets located in suitable habitat in southwestern Wisconsin in an attempt to document N. humeralis. In eleven nights of netting we captured 102 little brown bats (Myotis lucifugus), 6 northern long-eared bats (Myotis septentrionalis), 40 big brown bats (Eptesicus fuscus), 15 eastern red bats (Lasiurus borealis), 1 hoary bat (Lasiurus cinereus), 15 eastern pipistrelle bats (Pipistrellus subflavus) and 3 silver-haired bats (Lasionycteris noctivagans), the last species being a new record in Grant County. Considering the sampling effort evidenced by documentation of one new species if N. humeralis is present in the state, we feel it exists in low numbers. This study was part of the Wisconsin Bat Conservation and Management Plan. Introduction The evening bat is a medium sized bat that averages between 5 and 8 grams in weight (Hoffmeister 1989). It roosts in trees and sometimes buildings, and can be found foraging in forests and other wooded areas (Menzel 2001). Its diet consists mainly of insects (Hoffmeister 1989). The evening bat has a large geographic range that extends from the gulf coast to the great lakes (Hoffmeister 1989). It is rare in its northern range and its northernmost record is in central Michigan (Bowles 1975). The evening bat has been documented in northern Illinois and eastern Iowa, but it has never been documented in Wisconsin (Hoffmeister 1989). Wisconsin exhibits suitable habitat for the evening bat and is in close proximity to where the evening bat has been found previously (Hoffmeister 1989). So why has the evening bat not been found in Wisconsin? This was the main question of our research this past summer. Is the evening bat present in Wisconsin, or is it undetected due to a lack of sampling? The objective of my study was to conduct a survey of bats in southern, and particularly southwestern, Wisconsin, with a focus on selecting survey sites that exhibit suitable evening bat habitat. But why is it The Big M, Vol IV,

2 important to conduct surveys? Surveys are important because geographic distributions can change. Humans can alter and destroy the habitats of many species of plants and animals. Humans also introduce non-native species into the environment that can negatively affect native species, and finally climate is always changing and species may move with the climate (Schmitz 2003). Methods The best way to conduct a survey of bats is to get them in hand. To do this we used fine mesh nets called mist nets. These nets were either 18 or 30 feet long. When using mist nets it is important to pick a good location. Bats are able to maneuver through the forests with ease. This is because they are able to echolocate and they are able to detect our nets. To remedy this we set our nets in a corridor such as a stream or road. Bats use these corridors while foraging, as they are the path of least resistance. We then set our nets below an obstruction in the corridor as it will force the bats up or down into our nets. During our survey we visited six different sites. Before visiting the sites, we used the DNR program Webview to select sites that exhibited suitable evening bat habitat. After selecting a few sites we visited them to assess the habitat. If we found a suitable site, we contacted the landowners and gained permission to net on their property. Six sited were visited during our survey for a total of 11 nights. We would arrive at the site at around 7:00PM. After we arrived we would set up our net. Once the nets are up we record notes including location, temperature, % humidity, and key features of the stream or corridor. As a bat flies into our net, we would walk to the net and gently remove the bat. Once the bat was in hand we would transfer it into a paper cup with a lid and save the bat for processing at the end of the evening. We kept our nets open until about 11:00PM when The Big M, Vol IV,

3 bat activity started to decrease. The nets were taken down and all gear was brought back to the vehicles where we would then process the bats. Each bat was weighed, sexed, and identified to species. We would then measure forearm length, and any key morphological notes were taken down. Reproductive condition was also recorded Jun 924 pm Myotis lucifugus M NR Adult released 30', 18' Jun 924 pm Myotis lucifugus M NR Adult released 30', 18' Jun 926 pm Myotis lucifugus M NR Adult released 30', 18' Jun 954 pm Myotis lucifugus M NR Adult released 30', 18' Jun 955 pm Myotis lucifugus M NR Adult 38 8 released 30', 18' Jun 1032 pm Myotis lucifugus F lact - milk Adult released 30', 18' Jun 1115 pm Myotis lucifugus M NR Adult released 30', 18' Jun 1115 pm Myotis lucifugus F Preg Adult released 30', 18' Figure 1: Sample of data recorded from one site on June 14, 2007 Results In eleven nights of netting we captured 182 total bats. We caught all seven species known to inhabit Wisconsin including the species Lasionycteris noctivagans which is the first time it has been recorded in Grant County. Refer to figure 2 for total species count. We did not capture the evening bat during our survey. The Big M, Vol IV,

4 Total Species Count Total Numbe Eptesicus fuscu Lasionycteris noctivag 15 3 Lasiurus boreali Lasiurus cinereu 6 1 Myotis lucifugu Myotis septentriona Pipistrellus subflav 15 Bat Species Figure 2: Total species counts for summer of 2008 Discussion Although we did not find the evening bat, it is possible that it exists within the state in low numbers. The evening bat is rare in its northern range, and it is not found with much frequency in the states bordering Wisconsin. If the evening bat does exist within the state it would be in low number. However, because our survey did document all bat species known to regularly inhabit Wisconsin, it is equally likely that the evening bat currently remains absent from Wisconsin. The results of our survey also show that the habitat at our study sites was suitable for all bat species that inhabit Wisconsin and would be suitable for the evening bat. The Big M, Vol IV,

5 Citations Bowles, John B Distributions and Biogeography of Mammals of Iowa. Texas Tech Press, Lubbock, TX. Pg Hoffmeister, Donald.F Mammals of Illinois. The University of Illinois Press. Chicago, IL. Pg Long, C.A The occurrence, status and important of bats in Wisconsin with a key to the species. Transactions of the Wisconsin Academy of Sciences, Arts and Letter. Vol. 64 Pg Menzel, Michael A., Carter, Timothy C., Ford, Mark W., Chapman, Brian R Tree-roost Characteristics of Sub adult and Female Adult Evening Bats (Nycticeius humeralis) in the Upper Coastal Plain of South Carolina. The American Midland Naturalist. Vol Issue 1. Pg Schmitz, Oswald J., Post, Eric., Burns, Catherine E., Johnston, Kevin M Ecosystem Responses to Global Climate Change: Moving Beyond Color Mapping. Bioscience. Vol. 53, Issue 12. Pg Watkins, Larry C. Mammalian Species. The American Society of Mammologists. Vol. 23 Pg. 1-4 The Big M, Vol IV,