- December 14, 2016
As the day draws to a close and the sun settles on the horizon, the bees and butterflies retire their pollination services and the bug-eating birds bed down for the night. In a small, dark, and secluded place a small mammal begins to stir, encouraged by the oncoming darkness and spurred by its voracious appetite. Across the landscape, fluttering from caves, cracks, and crevices emerges the night shift. From dusk till dawn, hundreds of species of bats around the world pick up where the light-lovers left off to perform their own work of pollination and pest control. You can enlist this effective ecological service-provider to patrol your property keeping insect populations in-check while also promoting the overall health of these furry flyers.
There are just shy of 50 species of bats in North America aloneopen_in_new. Depending on the environment in which they live bats will either eat insects, fruit, or nectar. In the Southwest, and down into Central America, nectivorous bats are important pollinators for over 300 plant species including banana, guava, and mango as well as other well-known plants like the agave and giant saguaro cactiopen_in_new. Flowers that attract pollinating bats are usually large, white or very pale, fragrant, contain copious nectar, and, of course, are open at night when bats are active.
Most bats in North America are insectivorous, each feeding on thousands of flying bugs every nightopen_in_new. Natural insect control, along with plant pollination, is an important ecological service that could cost billions of dollars to replicate with conventional methodsopen_in_new. Protecting and providing habitat for bats will help ensure that this valuable service is preserved. From providing food and shelter to reducing pesticide use, there are a number of ways you can help create safe habitat for bats, either on your property or in a green space nearby. In return, you may receive a good amount of free pest control at no charge.
One way to easily provide beneficial habitat for bats is to create safe and secure shelter in the form of bat houses. Bat houses mimic places in the natural environment that offer a safe place from predators, and, if installed correctly, provide the perfect temperature and humidity for bats. Many species of bats will even use bat houses to establish maternity colonies, where sometimes hundreds of females raise young together.
Bat houses, whether built or bought, generally have between one to five chambers built into them. Larger maternity houses can contain ten or more. The more chambers in your bat house the more bats can occupy it. While it isn’t necessary to worry too much about the number of roosting chambers, a basic rule-of-thumb is that more is better. Single-chambered houses will need to be mounted on the wall of wooden or masonry buildings to buffer temperature fluctuations. Houses with at least three chambers maintain steadier temperatures and can house larger nursery colonies.
Your geographic location will determine when bats are most active and are most likely to use the bat house you’ve provided. Across the country various species of bats will enter and emerge from hibernation at different times of the year depending on climate and availability of food and other resources. After emerging from their winter hibernation, bats will look for bat houses and other places to roost during warmer months. Female bats roost in maternity colonies in the spring and begin to disband in the late summer or early fall, eventually abandoning the roosting site until the following year.
A typical bat house can be made at home using a variety of materials and following some general guidelines. Taller and wider is better and a good design will be at least 2 feet tall, around 12-14 inches wide, and will include a slanted roof to keep wet weather out. Larger houses should also include small vents in the exterior to help moderate temperatures and provide fresh air. The interior chambers should be at least 20 inches tall and as wide as the house with only about ¾ to 1-inch spacing between the chambers. Panels separating the chambers will need to be scored, or roughed-up, to provide traction and grip. Bats will also need a rough textured landing pad underneath the chambers to land on before they climb up inside. This can be a piece of cedar bark, plastic mesh, or scored wood like the chambers.
A Rocketbox is another very effective design you can build at home for attracting and safely housing bats. A Rocketbox includes several tall chambers nested inside each other that fit on a high pole. Its unique design provides a continuous 360 degree chamber which allows bats the freedom to find optimum temperatures. This style also allows for a sand or gravel filled central chamber that will absorb heat during the day and moderate the bat house temperatures on cool nights.
Bat houses can be mounted on wooden posts, steel poles, pivot poles, or on the sides of buildings. It is not recommended to mount bat houses on trees as the canopy may shade the house keeping it cooler than bats like. The tree’s branches can reduce the clearance to the entrance and may increase the risk of predation to roosting bat pups by making them easier to access. Typically, bat houses are mounted at least 15 feet above the ground –the higher the house the greater the chance of attracting bats. The height of the bat house is just one factor that can help bats discover the new roost. Be patient, it may take bats a couple seasons to find a new house. Try putting up several, in various locations, to see where bats prefer.
The temperature of your bat house affects whether or not bats will take up residency. The placement of your bat house will play a major role determining the internal temperature. Bat houses in colder climates should be mounted in an area that gets 6-8 hours of direct sunlight (facing either East or South) throughout the day. Those in warmer climates may be better off facing north or west to avoid becoming too hot. Single chambered bat houses should be mounted against a wall to avoid excessive heat loss. You might even consider putting up more than one bat house in different locations with slightly different temperatures, such as on different sides of your house, so that bats can move between them when temperatures fluctuate.
Since the color you paint the roost affects the amount of light and heat it absorbs, you can influence the box’s internal temperature with the color you paint it. Color recommendations for bat houses are based on average daily high temperatures in July. Bat houses in northern and high-altitude climates (in blue above) with average temps below 85F degrees should be painted with black or dark paint. From the South through the Midwest and the high deserts of the West (in green above), with around 85F-95F degree average highs, the bat houses should be dark to medium shades of color. In areas with high temps ranging from 95F- 100F degrees (shown in yellow), use medium to light shades of color and with average highs of 100F degrees plus, such as in the Southwest (shown in white), bat houses should only be painted white.
Even with the right color, a bat house can still get too hot in the summer when maternity roosts become crowded. Young bat pups and their mothers, when too hot, become weak and can fall out. Being weak and exhausted, they are not likely to survive. A simple pup catcher attached to the bottom of a bat house can help prevent this. Use a strip of plastic mesh to create a four-inch pocket at the end of a 24-inch length. Be sure the width is the same as the bat house and attach the top edge to the bottom of the landing pad. Secure the pocket end to the post and make sure it will stay open. If a bat falls out of the house this will give them a safe place to land and a way to climb back into the bat house.
Bats need more than shelter to feel at home. Placing your bat house near a pond, stream, or lake will provide water and will attract bugs for food. Planting native flowers, trees, and shrubs will also help by providing the habitat that creates many of the bugs that bats eat. Plus, native plants often require fewer pesticides and fertilizers to grow, making the food that bats eat much safer and healthieropen_in_new.
It’s never been a better time to help bats. Besides habitat loss, another factor affecting bats is white-nose syndrome, a devastating disease that has already killed millions of bats in the Northeast, and is moving westwardsopen_in_new. In 2016 it was found in Washington state. White-nose syndrome is a fungal disease that affects bats when they are hibernating, causing them to burn up energy resources so that they are unable to make it through the winter. Providing bats with habitat and shelter in the form of bat houses helps keep bats healthy during the warmer months of the year and provides roosting and nursery locations where bats can start to recover from white-nose syndromeopen_in_new.
Add a Bat House to your Map
First, find the Bat House object to place it on your map. It is located in the Tool Shed under Third. Scroll to the right using the arrows on the toolbar that pops up to find the Bat House. Click it once to select it then click on the map where’d you’d like to place it and drag it open to the size you’d like. You can always change its size and position using the lock/unlock from editing box.
Double click on the Bat House to add important data and show off your conservation efforts. You can give your Bat House a name or title in Basic Information. Then click Characteristics to tell us about it. Don’t forget, you can also make comments about the Bat House and upload pictures of it. We want to see your Bat House in action!