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Bats | |
Bats belong to the order Chiroptera, which means "handwing" They are the only mammal that can truly fly. Florida has 13 resident bat species. Contrary to popular belief, bats are not blind. Their vision is adapted for low light levels. However, bats can maneuver in complete darkness using echolocation. Echolocation is the use of sound waves to detect objects. Bats emit high pitched sounds and listen for them to echo back. The length of time it takes the echo to return tells the bat how far away it is from an object. This allows the bat to fly in the dark and hunt for food. Bats’ feet are uniquely adapted for grasping structures so that they can rest while hanging upside down. Bats undergo a state of torpor in the daytime; their heart rate and body temperature decrease so that they can conserve energy. Because of this, bats are reluctant to fly in the daytime even when disturbed. If they are forced to fly, they must first raise their body temperature and heart rate. Florida’s native bats are insectivorous, meaning they eat insects including beetles, mosquitoes, moths, and other agriculture and garden pests. In fact, bats are the most important controller of night flying insects because a single bat can eat up to 3,000 insects a night! Some bats, like the Brazilian free-tailed bat, the evening bat, and the big brown bat are colonial meaning they gather together in a colony to roost during the day. Colonial bat habitats include cracks, crevices, hollows of trees, caves, and manmade structures including buildings, bridges, tile roofs, and bat houses. Other species in Florida are solitary and live in dead fronds of palm trees, Spanish moss, and tree foliage. In Florida, bats mostly mate in the fall and winter. The female does not usually ovulate until the spring when the insect population increases, but she can retain sperm for months before ovulation occurs. Most female bats only have one pup per year. For their size, bats are the slowest reproducing mammals. Pregnant females of some species will gather together in nursery colonies. Bats do not build nests. They normally give birth from mid-April through July, and their young begin to fly within 3 to 6 weeks. Juveniles are then weaned from their mothers and by mid-August the young are able to forage and fly on their own. Bats will not reach reproductive maturity until they are about one year old. This is considerably longer than most small mammals. Bat populations are declining in many areas. The loss of roosting sites (such as trees and caves) can cause bats to roost in areas where they are more likely to become a nuisance for people. The use of pesticides to control insects can take away the food that bats eat, and sometimes poison the bats themselves. These unique mammals have been sensationalized in the news and horror movies, creating a great deal of anxiety among Americans. Fear of rabid bats has caused mass destruction of bat populations for decades even though they seldom pose public health problems. Ironically, this fear has caused more people to come in contact with bats while attempting to eradicate them! Rabies, a virus usually transmitted from a bite, affects a very small portion of the bat population in Florida. Histoplasmosis is a respiratory illness caused by a fungus. This fungus is found in soil that is enriched with bat or bird feces. This fungus is sometimes found on chicken farms or in caves. According to the Florida Bat Conservancy, "this illness has been associated with bats in Florida in only a few cases, all of which involved visits to bat caves" Attics and roofs are normally dry areas that do not provide the proper conditions for this fungus to survive. For more information about bats and rabies or histoplasmosis, including what to do if a person makes contact with a bat, contact the Centers for Disease Control and Prevention (CDC). Bats, like many other wildlife species, have lost a great deal of natural habitat to development. Some species have been able to adapt to habitat loss by moving into man-made structures. Female bats of some species will roost in large colonies when they have their pups. The potential of exterminating large numbers of bats at once means that bat populations are particularly vulnerable to extirpation. When bats take up residence in a structure where they are not wanted, there is only one safe, legal, and effective technique for getting rid of them. The process is known as "exclusion”. Excluding bats from their roost sites involves the use of a one-way device which allows them to exit the structure, but prevents them from returning. Exclusion devices should be used for four consecutive days before the opening is sealed. However, when outdoor temperatures begin to drop, so does insect activity. Therefore, when colder weather comes to Florida, there is little food available and bats may become inactive. Some bats might not exit the structure in which they roost during cold weather. In order to keep bats from being trapped inside of a structure, bat exclusion devices may not be used if the National Weather Service forecasts four consecutive days of the minimum temperature below 50 degrees Fahrenheit. Following exclusion, the structure needs to be rendered inaccessible to prevent recolonization by sealing all entrance points. These small mammals can enter a building through the tiniest of openings. Bat-proofing can be as easy as performing a few simple, energy-efficient home improvements such as applying caulking, and weather stripping. Bats are a very important natural resource for Florida because each bat can eat up to 3000 insects, including mosquitoes and agriculture pests, per night. Bat guano (feces) has been used for centuries as a nutrient rich fertilizer and is still highly prized by gardeners. It is illegal to kill bats in Florida in accordance with Florida Administrative Code number 68A-4.001 General Prohibitions and 68A-9.010 Taking Nuisance Wildlife. The use of pesticides or poisons for the purpose of harming, killing, or deterring bats is prohibited in the state of Florida, with the exception of one registered repellent: naphthalene (also known as moth balls). In order to avoid illegal take of bats, a structure inhabited by bats should not be sealed without first conducting an exclusion. Repellents are not exclusionary devices and should only be used in conjunction with an exclusion device if the structure is going to be sealed. Due to the possibility of killing flightless pups by separating them from their mothers, exclusion is prohibited between April 16 and August 14. Exclusion is also prohibited if the National Weather Service forecasts four consecutive days of minimum temperatures below 50 degrees Fahrenheit.
What is White Nose Syndrome in Bats? White Nose Syndrome (WNS) is named for a white fungus that has been found covering the muzzles of hibernating bats in the northeastern part of the United States. Thousands of bats with WNS have died. However, researchers are uncertain whether the fungus is causing the bats to die, or the fungus is secondary to some other primary cause of death, such as a virus or environmental contaminant. Bats known to be affected by WNS include the eastern pipistrelle, northern long-eared bat, small-footed bat, little brown bat, and the Indiana bat, which is protected by the Endangered Species Act. Why does this issue matter for Floridians? No cases of WNS have been found in Florida, but WNS is apparently spreading and biologists are still not certain whether bats or people, or both bats and people are transmitting WNS to new sites. Bats affected with WNS have been found in caves in New York, Vermont, Massachusetts, and Connecticut. In Florida, we have three species of bats that often roost in caves and there is an active community of "cavers" - people who regularly explore caves. Cavers that travel to the northeastern United States and explore caves there should disinfect their equipment as described in the information at the link below. This will help ensure that WNS is not transmitted to bats that roost in Florida caves. Anyone in Florida who finds bats that appear sick, or are acting in an unusual manner, should report that information by calling FWC's Wildlife Alert phone number. Bats affected by WNS do not always have the white fungus, instead they may only appear emaciated or severely dehydrated. Other signs of WNS include bats flying outside or near cave openings during the day, and dead or dying bats on the ground. Human health implications of WNS are not known, but there is no indication that people have been affected by WNS or exposure sick bats. Regardless, the public should never handle sick, injured, or dead bats. For additional information on WNS and methods to appropriately disinfect caving equipment, go to this link: http://www.fws.gov/northeast/white_nose.html More information:FWC Bat Links Bats and Human Health The Centers For Disease Control and Prevention (CDC) Bat Conservation Organizations The Florida Bat Conservancy For additional technical assistance you may contact the FWC Regional office nearest you. | |
Our mission: Managing fish and wildlife resources for their long-term well-being and the benefit of people.
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