Biological control is a pillar of integrated pest management. It may seem a bit daunting the principle is simple. All things in nature have predators including insects. Biological control is simply building a conducive environment for the predators of undesired pests. One animal not often thought of in this capacity is bats. Insectivores by nature, these underutilized creatures have a big impact to your open spaces. Their steady diet of moths (Lepidoptera), beetles (Coleoptera) and flies (Diptera, which includes mosquitoes) reduce insect pressure to your gardens and landscaping.
I know what you are thinking. How effective can they possibly be? Pregnant females consume up to two thirds of their body weight through the summer months while rearing pups. Bats are small but keep in mind that these are not solitary animals. In south Texas, a single large colony consumes enough insects to save cotton farmers an estimated $741,000 per year in insecticides. That is just to illustrate the point as you won’t be able to attract huge colony. There is no reason to believe a smaller colony will not provide similar services in your gardens.
Habitat
Now that your interest is piqued, how can you attract bats to your property? Installing a bat house is the easiest way. They are typically a two foot by one foot structure holding single or multiple chambers in which bats roost. It provides shelter from predation and weather while providing a place to rear pups. Though commercially available they may be built at home with minimal cost. Place the bat house in a location with morning sun at least 12 feet off the ground. Ensure there is enough airflow around the house to keep them cool, but that the structure is watertight. Mount houses on poles next to buildings and you’ll have better success attracting residents. With everything in place, it is time to discover who will most likely be your new neighbor.
photo: Joshua Criss
The Bats of North Florida
Florida is home to 13 species of bats statewide. Of these, 11 may be found in the Panhandle but only 3 are common enough to be routinely seen. The Brazilian free-tailed bat (Tadarida brasiliensis) is the most common. Medium sized with brown fur, they have a long tail, wrinkled cheeks, and roost in man-made structures.
Photo: IFAS
Second most common are Evening bats (Nycticeius humeralis). These dark brown to yellow bats have short ears with a broad hairless muzzle. They are tolerant of other bat species often roosting in tandem with them.
Photo: IFAS
Finally, the panhandle is home to Southeastern Myotis (Myotis austroriparius). Easily the smallest of these bats, they are dull gray to brown with a lighter belly and long hairs between their toes. This species is the bat most likely to eat mosquitoes.
Photo: Jeff Gore, FWC
Finally, the panhandle is home to Southeastern Myotis (Myotis austroriparius). Easily the smallest of these bats, they are dull gray to brown with a lighter belly and long hairs between their toes. This species is the bat most likely to eat mosquitoes.
A Word of Caution
No article on wildlife would be complete without a word of caution. Bats are wild animals and should be treated as such. Never touch a bat on the ground as it most likely is not healthy. Bats do not generally cause issues but have been known to be disease vectors. Call a professional to collect the animal and never bring it into your home.
Bats can be a wonderful tool in controlling pests on your property. Creating habitat can help reduce pesticide need and cost to the homeowner. For more information on bats, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
Bats give birth upside down–and a nursing female bat can eat up to 4,000 insects per night! Photo credit: Carrie Stevenson, UF IFAS Extension
I have a soft spot for bats. I know, I know, they give people the creeps and can show up in unwanted places (like attics and sheds). But collectively, the bats in our communities eat millions of mosquitoes and agricultural pests every night. Without them, we’d be overrun with insects, disease, and damaged crops.
This mother bat and two of her babies are nearly the same size. Female bats nurse and care for their newborns until they can fly on their own. Photo credit: Carrie Stevenson, UF IFAS Extension
As a mom, I also have the utmost respect for bat mothers. When a member of this acrobatic species gives birth, it’s done while hanging upside down by her feet. When the baby is born, mom catches it in her wings and the newborn crawls up to her abdomen. Bat babies are not tiny, either—at birth, they are typically up to a third of an adult bat’s weight. Can you imagine giving birth to a 40-50+ pound baby, while hanging from your feet? Thankfully, most births are single pups, but occasionally multiples are born. Through our local wildlife sanctuary, I once met an exhausted bat mother of triplets. She and her new brood were found together on the ground—mom was unable to carry all three with her as she flew.
Summer is maternity season for female bats, typically giving birth in May or June. Being fellow mammals, bats must stay near their newborns to nurse. It takes about three weeks for juvenile bats to learn to fly. During that time, they either cling to their mother, nursing on the road, or stay behind in a maternity colony as she feeds at night. For that reason, during the period from April 16-August 14, it is illegal to “exclude” or prevent bats from returning to their roost—even if it’s your attic. Blocking a bat’s re-entry during this time frame could result in helpless newborn bats getting trapped in a building.
Hundreds of thousands of bats emerge from the Congress Avenue bridge in downtown Austin, TX on a summer night. Photo credit: Visit Austin
So, if you have seen evidence of bats flying in and out of your attic—or another building that should not house them—you will need to wait until August 15 or later. Excluding bats from a building entails waiting for the bats to fly out at night and putting up some sort of barrier to prevent their return. This can be done using several different methods explained in this video or by using a reputable wildlife professional. The Florida Fish & Wildlife Conservation Commission has regulatory oversight for bat-related issues, and they will work with homeowners to arrange a positive outcome for both the homeowner and the animals involved.
The bat houses on UF’s campus house are home to approximately a half million bats. Photo credit: Carrie Stevenson, UF IFAS Extension
On just about any spring or summer night at dusk, you can look up and see bats darting around, chasing and catching insects. If you are a total bat nerd like me, there are also several places around the southeast with large bat houses for public viewing. In Gainesville, the University of Florida bat houses are home to over 450,000 bats that leave the houses every night. An even larger colony in Austin, Texas (750,000-1.5 million bats) flies out at sunset every night to forage from their dwelling under a downtown bridge. Both are fascinating experiences, and worth a visit!
If you’re interested in building a bat house for your own backyard, reach out (ctsteven@ufl.edu); I have examples at the office and several sets of plans for building bat houses and installing them correctly. The publication, “Effective Bat Houses for Florida” goes through the best way to figure out where to place a house and includes a set of plans.
Bats bring a beneficial component to your property and community. This flying mammal is an exceptional nocturnal feeder of many insect pests and they are important pollinators of many food plants. However, several challenges face this night flyer, like reduced roosting locations, reduced foraging sights, and over use of pesticides.
Photo courtesy: Stephen Greer
There are ways to attract bats to your backyard, farm, and community. Placement of bat boxes with ample water sources nearby is a good start. Water sources are another area of importance to attract bats. Have you sat by a swimming pool and witnessed a bat swoop down and skim across the water? It is likely they are either consuming a little water after feeding on a large number of harmful insects or are wetting their modified arms (wings) to help remove dust and dirt to reduce drag on their wings. Bats are the only mammal that are capable of true flight, the modified wings with skin spanning between specific bone structures allows them to accomplish this amazing action.
We often refer to bats as blind, but they can see shadows if out during daylight hours. This poor sight is not helpful enough for survival, this is where their echolocation abilities come into play. Humans studied bats to better understand how they make the sounds that bounce of an object and back to their sensing system that includes exceptional hearing. They locate and consume insects this way. If this sounds familiar, sonar systems were developed by studying this process.
Bats are the major harvester of night-flying insects, many that carry diseases that impact humans and other animals. Insect prey for bats include cockroaches, mosquitos, moths, beetles, gnats and others. A Big Brown Bat can catch and consume 3,000 to 7,000 mosquitos a night. Multiple this by a large bat population the amount of harmful insects harvested can go into the thousands of tons in a year. This is a positive impact for our forest and agriculture lands against major pests.
Florida is home to 13 different species of bats. They are always on the hunt for warm, dry, dark areas that are either natural or manmade narrow crevices. Out of all of these species, 4 bats are the primary inhabitants of bat houses. The Evening Bat and Brazilian free-tailed Bat are the most common in the panhandle of Florida. The Big Brown Bat and Southeastern Bat can at times occupy houses.
Photo courtesy: Matt Lollar
You can often locate bats boxes at your garden and agriculture centers or order online. Another option is to build your own boxes. Just remember the best way to erect a bat box is on a tall post. It is recommended to set the boxes around 10 feet off the ground. Placing boxes on trees creates a setting for potential predators to approach and feed on bats. Snakes have been known to enter and feed on young bats that are not fully developed and at best are poor fliers.
As a reminder, never touch a bat or any other wild animals. Bats that are healthy are not found on the ground, so assume the bat is not health and may be carrying a disease. On a final note, enjoy sitting on the back porch and watching the acrobatics of these amazing mammals in the evening sky.
For the 13th year we celebrate National Pollinator Week June 22-28 to bring awareness to the importance of our pollinators and the challenges they face. This is an opportunity to learn about ways to protect pollinators in our own landscapes. Every one of us can make a difference.
When we hear the word ‘pollinator’ most of us immediately think of honeybees. They are very important but there are so many other creatures that are important pollinators:
Native bees – Florida alone has over 300 species of bees
Hummingbirds – their long beaks can reach into long, tubular blooms
Bats – they pollinate over 500 plants including banana, mango, and agave (used to make tequila)
Beetles – considered to be a messy and minor pollinator; they pollinate the native paw paw
Butterflies – a minor pollinator as most have long legs that keep them perched above the pollen
Flies – pollinators of a variety of native plants
According to the USDA, 75% of flowering plants and about 35% of food crops around the globe rely on these animals for pollination. Without pollination, these plants would not reproduce or provide us food.
So, what can the average person do to make a difference?
Avoid using any insecticide unless it is absolutely necessary. Predators like assassin bugs, dragonflies and birds help to keep pests in check. Our songbirds rely on protein-rich insects (especially caterpillars) to feed their growing babies.
Don’t treat areas where pollinators are visiting the flowers, whether in the lawn or the landscape beds.
If you need to apply an insecticide to the lawn, mow first to remove the blooms from any weeds. Always follow the label instructions carefully.
Avoid using a systemic insecticide on plants that bloom and attract pollinators. The insecticide can remain in plants for a long time.
Landscape activities have already begun in our Panhandle counties with cleanup, mulching, raking, and pruning. Our mild temperatures and days with sunshine spur us to jump into our landscape preparations for the spring growing season.
This year before you send all your debris to the compost pile or patch up thinning turf areas, consider that some landscape imperfections may actually be good for local wildlife.
We all know how important it is to plant nectar attracting plants for bees but there are other easy practices that can help promote more native bees in local landscapes. There are some solitary native bee pollinators that will raise young in hollow stems of plants. Instead of cutting all your old perennial or small fruit stems back to the ground, let some stay as a home to a native pollinating bee. This does not have to detract from the look of the landscape but can be on plants in the background of a border garden or even hidden within the regrowth of a multi stemmed plants. Plants that are especially attractive to native bees have a pithy or hollow stems such as blackberry, elderberry, and winged sumac.
The hollow stems of upright blackberries can be home to solitary bees. Photo by Beth Bolles, UF IFAS Extension Escambia County
Another favorite site for solitary bees is in the ground. These ground nesting solitary bees should not be compared to yellow jacket wasps. Solitary bees are not aggressive. Mining or digger bees need some bare soil surfaces in order to excavate small tunnels for raising a few young. Maybe you have an area that does not need a complete cover of turf but is fine with a mixture of turf and ‘wildflowers’. A few open spaces, especially in late winter and early spring will be very attractive to solitary bees.
Beneficial solitary bee mounds in the ground of a winter centipedegrass lawn area. Photo by Beth Bolles, UF IFAS Extension Escambia County
One of our fastest disappearing homes for wildlife are natural cavities. In residential sites, we often prune or remove limbs or trees that are declining or have died. If the plant or tree is not a hazard, why not leave it to be a home for cavity nesting birds and mammals. If the dying tree is large, have a professional remove hazard pieces but leave a trunk about 10-15 feet tall for the animals to make a home. You may then get to enjoy the sites and/or sounds of woodpeckers, bluebirds, owls, flying squirrels, and chickadees.
One of the incredible benefits of living in Florida is exposure to the biodiversity of our wildlife population. From ordinary squirrels and mockingbirds to the more exotic panthers and migratory tropical birds, it is rare one can step outside the house without seeing or hearing wildlife of some variety. One of the practices we “preach” here at Extension is to provide habitat for wildlife in our yards and gardens. While cities and neighborhoods are human-centric, we share these spaces with thousands of wild animals, birds, fish, and insects and should always consider them in our actions.
Attracting birds and butterflies are popular pastimes, and Extension faculty can provide a tremendous amount of information on their preferences and food sources. However, a few unsung critters deserve homes and space as well. Just yesterday, I took a call from a gentleman who was excited to discover a small colony of bats roosting in a tree on his property. He was looking for ways to encourage them to stay, because he realized the countless benefits they provide in free insect control. Many people are nervous around bats of because of their unpredictable, irregular night flight pattern and association with scary stories. However, an average Florida bat can eat 1,000 insects a night, keeping pest populations down, reducing mosquito-borne disease, and saving millions of dollars in crop damage.
In our demonstration garden today, I was delighted to walk up on a black racer sunning itself in the grass. These common garden snakes provide valuable pest control of rats and mice, and are not aggressive or venomous. The fear of snakes often comes from the surprise of finding one unexpectedly, so always be alert and observant when outdoors. Respect for these creatures and a basic working knowledge of common venomous and nonvenomous species can go a long way towards calming one’s nerves. An excellent resource for snake identification in north Florida is this online guide. Like many snakes, this particular snake had been in tall grass, so it is always wise to be cautious in those areas.
This black racer sunning in the grass must have gotten the message about utilizing habitat provided for wildlife! Photo credit: Carrie Stevenson, UF IFAS Extension
To attract wildlife, learn about their life cycle and food sources, and provide shelter, water, and food for the species you are interested in attracting. Keep in mind that inviting wildlife may also draw their predators, but know that this is part of the larger cycle. Always keep safety in mind, and if necessary keep tall vegetation and deep water to a minimum in play areas frequented by young children. The benefits of providing food and shelter for wildlife are countless for human observers and wildlife alike.
