Appearance
The tricolored bat has unique tricolored fur, with dark roots, a pale midsection, and brown tips giving them a yellowish or buffy brown appearance (Reid 2006). The tricolored bat is Florida’s smallest bat, with a wingspan of approximately 9 inches, a body length of around 1 3/4 inches, and a weight of just 0.2 ounces (6 grams). Tricolored bats are unique in that they have dark wings contrasting with pink forearms (Florida Bat Conservancy 2005).
Behavior
Merlin Tuttle photo used with permission
Tricolored bats are generalist insectivores, which means they are able to eat many different kinds of insects. However, primary prey items include small beetles, mosquitoes, and moths (Weinkauf et al. 2018). Tricolored bats come out at sunset and eat while flying a slow erratic pattern (Reid 2006). Like most bats, tricolored bats use echolocation to find their prey. By frequently emitting high-pitched calls and listening to the echo, they can home in on an insect’s exact location as they fly by (Simmons et al. 1996).
Tricolored bats mate in the fall and give birth in the spring after hibernation. Females often form small maternity colonies where they give birth to two offspring (Wimsatt 1945). Males usually roost singly throughout the year. Tricolored bats do not appear to travel very far for food. Field observations indicate that tricolored bats remain within 0.3 miles (0.5km) of their roost. They search for flying insects by flying in circles anywhere between 40 and 200 feet wide (12-60m) about 3-6 feet (1-2m) above the tree top level (Caire et al. 1984). Most tricolored bats are residents of the same area all year long. However, some bats make large regional migrations from north to south, and in Florida some bats even move from south to north in the Fall to reach hibernation sites (Fraser et al. 2012, Smith et al. 2022).
Habitat
Tricolored bats search for food near or directly over water, in fields, and along forest edges (Cable and Willcox 2024). Little is known about habitat requirements in Florida, but they are common in Pine Rocklands in the Greater Everglades during the warm-wet season (Braun de Torrez et al. 2017). In Florida, the tricolored bat hibernates during the winter, beginning in mid-November until the bat awakens sometime in March (Smith, in review). Tricolored bats roost in caves, culverts, bridges, trees, and other structures (Smith et al. 2021, Smith et al, in review, Newman et al. 2021). Florida tricolored bats use both shallow and deep caves, but they are more abundant in longer, cooler caves (Smith et al. 2021). In summer, tricolored bats roost in Spanish moss and dead tree leaves. Tricolored bats prefer deciduous and mixed forests in areas with trees of various heights (Cable and Willcox 2024).
Threats
The tricolored bat is proposed for listing as federally endangered and is considered a Species of Greatest Conservation Need in Florida. In Florida, tricolored bats have declined by 70% since 2014 but the exact cause for this decline is unknown (Smith et al. 2023). Tricolored bats are threatened by several factors including white-nose syndrome, habitat loss and fragmentations, and climate change.
Disease: The greatest threat tricolored bats face is the disease called white-nose syndrome (WNS). WNS is caused by the fungus Pseudogymnoascus destructans, and has spread across North America (U.S. Fish and Wildlife Service [USFWS] 2020). White-nose syndrome causes widespread death in some cave bat populations by disrupting hibernation cycles, causing individuals to wake more frequently and use up fat reserves (Frick et al. 2010, 2015; Lorch et al. 2011; Warnecke et al. 2012). WNS has caused 90-100% declines in winter colonies at affected sites. Fortunately, WNS has not been detected in Florida yet, but it does occur in the neighboring states of Alabama and Georgia.
Habitat Loss: Deforestation is a major threat to tricolored bats everywhere, as it results in the loss of feeding and roosting habitat (Erickson and West 1996). Climate change is also predicted to have a negative impact on this species. As temperatures increase, tricolored bats may have to move further north in search of better hibernation conditions (Humphries et al. 2002, USFWS 2007). Longer distance movements are energetically costly and dangerous. Increased storm intensity associated with climate change may also result in roost loss or knocking the bats and the clumps of dead leaves within which they roost to the ground.
Other threats: Another emerging threat towards tricolored bats outside of Florida is wind turbines. Arnett and Baerwald (2013) estimated that roughly 45,000-94,000 tricolored bats were killed by wind turbines in the United States and Canada between 2000-2011. With wind energy becoming more popular, this threat may increase.
Conservation and Management
The tricolored bat is a Species of Greatest Conservation Need in the state of Florida. A proposal to list the species as endangered under the federal Endangered Species Act is currently under review.
These bats are monitored with the other bat species in Florida as part of the Long-term Bat Monitoring Program, which seeks to keep track of bat populations throughout the state. The program achieves this by placing ultrasonic detectors across the state that pick up and record calls of nearby bats. In addition, FWC performs yearly surveys of caves to check for the fungus that causes white-nose syndrome.
It is illegal to remove bats from structures or to otherwise handle them directly in the state of Florida. If you have bats in your house or other structure, please see our Living With Bats page to learn how to properly evict them.
How You Can Help
We are always glad to have volunteer help with our bat conservation work, particularly with the Long-term Bat Monitoring Program in which volunteers help place and monitor our acoustic detectors. If you are interested in volunteering with this program or in helping in other ways, please visit our Bat Force website to learn more.
References
Arnett, E. B., and E. F. Baerwald. 2013. Impacts of wind energy development on bats: implications for conservation. Pages 435-456 in R. A. Adams and S. C. Pedersen (editors). Bat evolution, ecology, and conservation. Springer Science+Business Media, New York.Arroyo-Cabrales, J., Miller, B., Reid, F., Cuarón, A.D. & de Grammont, P.C. 2008. Pipistrellus subflavus. The IUCN Red List of Threatened Species 2008:e.T17366A7011135.
Braun de Torrez, E.C., Ober, H.K., McCleery, R.A., 2017. Critically imperiled forest fragment supports bat diversity and activity within a subtropical grassland. Journal of Mammalogy, xx(x):1–10.
Cable, A.B. and E.V. Willcox. 2024. Summer habitat for the female tricolored bat (Perimyotis subflavus) in Tennessee, United States. Journal of Mammalogy, gyae002, https://doi.org/10.1093/jmammal/gyae002
Caire, William, Smith, Jaynie F., McGuire, Sheri, Royce, Michael A., 1984. Early Foraging Behavior of Insectivorous Bats in Western Oklahoma. Journal of Mammalogy 65(2): 319-324.
Committee on the Status of Species at Risk in Ontario (COSSARO), 2015. Ontario Species at Risk Evaluation Report for Tri-colored Bat (Perimyotis subflavus).
Davis, Wayne H., Mumford, Russell E., 1962. Ecological Notes on the Bat Pipistrellus subflavus. The American Midland Naturalist 68(2): 394-398.
Davis, Wayne H., 1964. Winter Awakening Patterns in the Bats Myotis lucifugus and Pipistrellus subflavus. Journal of Mammalogy 45(4): 645-647.
Duchamp, J.E., Sparks, D.W.,Whitaker, J.O., 2004. Foraging habitat selection by bats at an urban-rural interface: comparison between a successful and a less successful species. Canadian Journal of Zoology 82, 1157–1164.
Erickson, J.L., West, S.D., 1996. Managed forest in the Western Cascades: the effects of seral stage on bat habitat use patterns. In: Barclay, R.M.R., Brigham, R.M. (Eds.), Bats and Forests Symposium. British Columbia Ministry of Forests, Victoria, 215–227.
Evelyn, M.J., Stiles, D.A., Young, R.A., 2003. Conservation of bats in suburban landscape: roost selection by Myotis yumanensis in a residential area in California. Biological Conservation 115, 463–473.
Feldhamer, George A., Carter, Timothy C., Whitaker, John O, Jr., 2009. Prey Consumed by Eight Species of Insectivorous Bats from Southern Illinois. The American Midland Naturalist 162 (1):43-51
Florida Bat Conservancy, 2005. Tricolored bat (Eastern pipistrelle). Merritt Island, FL.
Fraser EE, McGuire LP, Eger JL, Longstaffe FJ, Fenton MB (2012) Evidence of Latitudinal Migration in Tri-colored Bats, Perimyotis subflavus. PLoS ONE 7(2): e31419.
Grindal, S., 1996. Habitat use by bats in fragmented forests. In: Barclay, R.M.R., Brigham, R.M. (Eds.), Bats and Forests Symposium. British Columbia Ministry of Forests, Victoria, 260–272.
Humphries, M. M. and D. W. Thomas, and J. R. Speakman. 2002. Climate-mediated energetic constraints on the distribution of hibernating mammals. Nature 418:313-316
Lacki, M.J, Amelon, S.K., Baker, M.D., 2007. Foraging ecology of bats in forests. In: Lacki, M.J., Hayes, J.P., Kurta, A. (Eds.), Bats in Forests. The John Hopkins University Press, Baltimore.
Menzel, M.A., Krishon, D.M., Carter, T.C., Laerm, J., 1999. Notes on tree roost characteristics of the northern yellow bat (Lasiurus intermedius), the Seminole bat (L. Seminolus), the evening bat (Nycticeius humeralis), and the eastern pipistrelle (Pipistrellus subflavus). Florida Scientist 62 (3/4): 185-193.
Newman, B.A., S.C. Loeb, and D.S. Jachowski. 2021. Winter roosting ecology of tricolored bats (Perimyotis subflavus) in trees and bridges. Journal of Mammalogy 102:1331-1341.
Patriquin, K.J., Barclay, R.M.R., 2003. Foraging by bats in cleared, thinned and unharvested boreal forest. Journal of Applied Ecology 40, 646–657.
Reid, F.A. 2006. Mammals of North America. Houghton Mifflin, Boston.
Russ, J.M., Montgomery, W.I., 2002. Habitat associations of bats in Northern Ireland: implications for conservation. Biological Conservation 108, 49–58.
Smith, L.M., T.J. Doonan, A.L. Sylvia, and J.A. Gore. 2021 Characteristics of Caves used by wintering bats in a subtropical environment. Journal of Fish and Wildlife Management 12:1-12.
Smith, L.M., J.A. Gore, T.J. Doonan, and C.J. Campbell. 2022. Tricolored bats at a southern range edge exhibit partial migration northward. Movement Ecology 10:1-13.
Smith, L.M., A. Sylvia, T.J. Doonan, and J.A. Gore 2023. Decline of Tricolored Bats (Perimyotis subflavus) in Florida caves in winter. Southeastern Naturalist 22:135-153.
Sparks, D.W., Ritzi, C.M., Duchamp, J.E., Whitaker, J.O., 2005. Foraging habitat of the Indiana bat (Myotis sodalis) at an urban-rural interface. Journal of Mammalogy 86, 713–718.
U.S. Fish and Wildlife Service, 2018. Tricolored bat (Perimyotis subflavus). Environmental Conservation Online System
Vanderwolf, K.J., D. Malloch, and D.F. McAlpine, 2015. Fungi associated with over-wintering tricolored bats, Perimyotis subflavus, in a white-nose syndrome region of eastern Canada. Journal of Cave and Karst Studies, 77(3): 145-151.
Vincent, Elizabeth A., Whitaker Jr., John O., 2007. Hibernation of the eastern pipistrelle, Perimyotis subflavus, in an abandoned mine in Vermillion County, Indiana, with some information on Myotis lucifugus. Proceedings of the Indiana Academy of Science 116(1):58-65.
Weikauf, C.A., C.E. Comer, W.C. Conway, and C. Farrell.2018. Dietary composition of four common chiropteran species in a bottomland hardwood forest. Acta Chiropterologica 20:195-205.
Weller, T.J., P.M. Cryan, and T.J. O’Shea. 2009. Broadening the focus of bat conservation and research in the USA for the 21st century. Endangered Species Research 8:129-145.
Wimsatt, William A., 1945. Notes on Breeding Behavior, Pregnancy, and Parturition in Some Vespertilionid Bats of the Eastern United States. Journal of Mammalogy 26 (1): 23-33.