Eastern Illinois University The Keep Masters Theses Student Theses & Publications 1997 Roost Site Selection of the Red Bat (Lasiurus borealis) Kenneth J. Mager Eastern Illinois University This research is a product of the graduate program in Zoology at Eastern Illinois University. Find out more about the program. Recommended Citation Mager, Kenneth J., "Roost Site Selection of the Red Bat (Lasiurus borealis)" (1997). Masters Theses. 1846. https://thekeep.eiu.edu/theses/1846 This is brought to you for free and open access by the Student Theses & Publications at The Keep. It has been accepted for inclusion in Masters Theses by an authorized administrator of The Keep. 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PLEASE SIGN ONE OF THE FOLLOWING STATEMENTS: Booth Library of Eastern Illinois University has my permission to lend my thesis to a reputable college or university for the purpose of copying it for inclusion in that institution's library or research holdings. ,,.,..--- / / c - '--~ -- 6 - 7// Date · I respectfully request Booth Library of Eastern Illinois University not allow my thesis to be reproduced because: uthor Date Roost site selection of the red bat (Lasiurus borealis) (TITLE) BY Kenneth J. Mager THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science IN THE GRADUATE SCHOOL, EASTERN ILLINOIS UNIVERSITY CHARLESTON. ILLl~OIS 1997 YEAR I HEREBY RECOMMEND THIS THESIS BE ACCEPTED AS FULFILLING THIS PART OF THE GRADUATE DEGREE CITED ABOVE DATE Roost site selection of the red bat (Lasiurus borealis) Kenneth J. Mager Masters Thesis Eastern Illinois University Charleston, IL ll To my Mother, Father, and Sister, I've got it covered! Always, Ill ABSTRACT I monitored the roosting activity and evaluated roost site selection of red bats (Lasiurus borea/is) at study sites in Coles County during the summer of 1996. Red bats were mist-netted and radio transmitters were affixed to 12 individuals. A total of 105 transmitter-days were recorded with 75 roost locations identified. The roost types consisted of eight different species of trees, prairie grass, and residential structures but the vast majority of roosts (92%) were in Jarge, deciduous trees. The height of the roosts ranged from 0.5 to 21.4 m, but 54.7% were between 5-10 m. Movement between consecutive roosts ranged from 0 to 733 m with 80% being less than 200 m. Reduced understory vegetation beneath roosts allowed for a less obstructed flight path. Red bats showed fidelity to their home ranges, but not to individual roost sites. Urban forests in central Illinois provide the essential habitat components for successful coloniz.ation by bat species and may constitute important habitat for this species. IV ACKNOWLEDGMENTS I would like to thank Glenn Lyons of Fox Ridge State Park, Rick Goebel of Hidden Springs State Forest, and Angela Smith of the Douglas-Hart Nature Center for their help in implementing this study. I am grateful for the assistance from Susan Latta and Stephanie Kavanaugh and to everyone else who spent long hours helping me in the field each night. I would like to thank the Biological Sciences Graduate Program and the Council for Faculty Research for funding of this project. I would also like to thank the faculty of the Zoology Department for their encouragement and support. I am especially indebted to Dr. Thomas Nelson, my advisor, for his encouragement and patience in this project. I am also grateful to his ftunily for their kindness and patience while using their house as a study area. I would also like to thank my committee members, Dr. Robert Fischer and Dr. Eric Bollinger for their guidance, advice, and constructive input on this manuscript. Finally, I would like to thank Alan Pilch, Ann Marie Hogan, Catherine Woodworth, Dan Lloyd, Dave Gregory, and Andy Miller for their friendship, support, and encouragement during this project. v TABLE OF CONTENTS Title page ...................................................................................................................... .i Dedication..................................................................................................................... ii Abstract ........................................................................................................................ iii Acknowledgnients........................................................................................................ .iv Table of contents........................................................................................................... v Introduction. .................................................................................................................. 1 Methods ........................................................................................................................ 4 Resuhs and Discussion. .................................................................................................. 9 Conclusion and Management lmplications.................................................................... 15 Literature cited............................................................................................................ 16 Tables.......................................................................................................................... 20 Figures......................................................................................................................... 25 fNTRODUCTION Bats are an integral part of many ecological communities, and can be economically important because they consume certain insect pests. Populations of many bat species are declining worldwide, apparently due to loss of critical habitat, pesticides, and harassment (Hill and Smith 1984). Unlike most small mammals, bats have difficulty recovering from population declines because they exhibit low reproductive rates and delayed sexual maturity (Barbour and Davis 1969). Among those species which may be declining in Illinois are the four tree roosting species: red bats (Lasiurus borealis), hoary bats (Lasiurus cinereus), silver-haired bats (Lasionycteris noctivagans), and Indiana bats (Myotis soda/is). The latter is federally endangered (Hoffineister 1989). It is difficult to monitor population status of tree-roosting bat species because they are solitary, widely dispersed, and difficult to observe. However, it is reasonable to assume that habitat changes such as loss of forest due to urbanization and agriculture, forest fragmentation, and removal of mature trees, cavity trees, and snags (Kurta and Teramino 1992) may have caused declines in these species in the Midwest. The potential impact of these activities on red bats is difficult to discern because relatively little is known about roost site selection by this species. To properly conserve red bats, a more detailed understanding of their habitat requirements is needed. Tree-roosting bats typically roost in foliage, tree cavities or under loose bark. Red bats have been observed roosting in trees and shrubs (Hall and Kelson 1959). Daytime roosts generally include forest edge habitats adjacent to streams, open fields or urban areas. However, it has also been reported that red bats occasionally roost on or near the ground (Hall and Kelson 1959). Early studies suggested that tree-roosting bats select 2 roosts that provide deep shade, are visible from below, lack branches from which predators might detect and attack them, are 1-3 m above the ground and are located over ground cover that reduces reflected light (Constantine 1958, 1966). Further, roosts may be selected because they provide thermal cover by reducing a bat's exposure to light and wind or because they are located close to preferred foraging areas. Selection of a suitable roost is vital for the survival of a migratory species since it is essential for bats to locate roosts in unfamiliar territory. Constantine (1966) suggests that an attracting odor remains with the roost after its use, or perhaps foraging bats observe roost use by another bat and consider it acceptable for future use. This hypothesis is supported by Downes' (1964) observations of five different red bats selecting one sunflower as the preferred roost site over the other flowers in the row. Therefore, it might be expected that these cues are used to reduce the time and energy required to locate roosts. The ability of a red bat to switch and locate a new suitable roost gives the bat access to a wider range of habitats. This in turn will reduce its dependence on a particular area. Bats with alternative roosts are more likely to survive possible destruction of their roosts (ie. environmental or human factors) compared to those species which rely on a single roost (Barclay et al. 1988). Research has shown that red bats preferred forest edge habitat to dense, mature deciduous forests for roosting (Constantine 1966, Kunz 1973). Furlonger et al. (1987) found red bats more often in terrestrial edge habitats than similar edges associated with water. The reduced amount of canopy cover and understory which is provided by