Art Credit: Sahina Irvin
Appearance
As its name suggests, the northern yellow bat has fur that ranges in color from yellow to a grayish-brown color (Florida Bat Conservancy). Their long, thick fur covers their bodies and the front half of their uropatagium, which is the membrane that stretches between their legs (Ober et al. 2016). The color of their fur camouflages the bats in their preferred tree roosting habitats. Female yellow bats are typically larger than males. They have a wingspan of about 14-16 inches and weigh about ½ to 1 ounce, making them one of Florida’s larger bat species (Animal Diversity Web).
Behavior
Northern yellow bats are insectivorous, meaning they eat insects. They eat a variety of flying insects, including beetles, flies, flying ants and leafhoppers (Florida Bat Conservancy). In Florida specifically, they also eat mosquitoes and other flies (National Park Service). They tend to emerge each night at dusk, flying 3-4 meters (10-13 feet) over open, grassy areas in groups of 100 or more (Barbour and Davis 1969). They will also hunt in human-built open areas such as airports, pastures, and golf courses (Miller and Rodriguez 2016). Like most bats, the species uses echolocation to find its prey, frequently emitting high-pitched calls and listening to the echo to home in on an insect’s exact location (Simmons et al. 1996).
Northern yellow bats do not migrate and are active year-round, except during periods of exceptionally cold weather (National Park Service). The species mates in fall and sometimes early winter. In Florida, females usually give birth to 3 or 4 pups at the beginning of the summer (Marks and Marks 2006). The pups learn to fly 3-4 weeks after being born, when they begin joining their mother on feeding flights in the evening.
Males and females stay separated for most of the year and are usually solitary. However, in the spring and summer, females will form small maternity colonies. When the young are able to fly, the mothers and pups will feed together in large gatherings. Males rarely participate in these feedings (Animal Diversity Web).
Habitat
The northern yellow bat is found throughout Florida, except for the Keys. They live in wooded areas near permanent freshwater sources or in coastal habitats with Spanish moss and/or palm trees (National Park Service). The northern yellow bat prefers to roost in the hanging dead palm fronds, where the yellow-brown coloration of their fur provides excellent camouflage, or in clumps of Spanish moss draped around hardwood trees. A single palm tree or oak tree covered in Spanish moss may contain many bats. They rarely roost in human occupied structures.
Threats
The main threats to northern yellow bats involve destruction of their habitat and food sources. In populated areas, dead palm fronds and Spanish moss are often intentionally removed by people. Because these are the species’ primary roosting habitat, this can reduce their ability to live in large portions of their range. Additionally, heavy use of pesticides not only reduces their food sources, but also harms their roosting abilities, as these bats will avoid these areas.
Fortunately, the two main threats to many bat species, habitat loss to human development and white-nose syndrome, do not seem to impact northern yellow bats significantly. They have proven very adaptable to human development (Rodriguez et al. 2016) and due to their behavior and roosting preferences, they are not susceptible to the fungus that causes white nose syndrome.
Conservation and Management
The Northern Yellow Bat is one of Florida's Species of Greatest Conservation Needs. 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.
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
Animal Diversity Web. Lasiurus intermedius. Retrieved from https://animaldiversity.org/accounts/Lasiurus_intermedius/
Barbour, R.W. and Davis, W.H. 1969. Bats of America. The University of Kentucky Press, Lexington, Kentucky.
Florida Bat Conservancy. Northern yellow bat. (n.d.). Florida Bat Conservancy. Retrieved from https://www.floridabats.org/northern-yellow-bat.html
Harvey, M.J.; Altenbach, J.S.; Best, T.L. 1999. Bats of the United States. John Hopkins University Press, Baltimore, Maryland.
Miller, B. & Rodriguez, B. 2016. Lasiurus intermedius (errata version published in 2017). The IUCN Red List of Threatened Species 2016: https://www.iucnredlist.org/species/11352/115101697
Marks, C. S., & Marks, G. E. (2006). Bats of Florida. The University Press of Florida.
National Park Service. Updated 17 Oct, 2017. Northern yellow bat - Everglades National Park (U.S ... (n.d.). National Park Service. Retrieved from https://home.nps.gov/ever/learn/nature/northernyellowbat.htm
Ober, H. K., Main, M. B., & Allen, G. M. (2016, December 14). Bats of Florida. Retrieved from http://edis.ifas.ufl.edu/uw203
Rodríguez-Aguilar, G., Orozco-Lugo, C. L., Vleut, I., & Vazquez, L.-B. (2016). Influence of urbanization on the occurrence and activity of aerial insectivorous bats. Urban Ecosystems, 20(2), 477–488.
Simmons, J., M. Ferragamo, T. Haresign, J. Fritz. Aug 1996. Representation of Perceptual Dimensions of Insect Prey During Terminal Pursuit by Echolocating Bats. Biological Bulletin, 191:(1): 109-121.