Spooky Science

The Winged Pool Guy

Installing a bat house is a great way to naturally reduce lawn and garden pests.

As Arizonans cope with the housing downturn, an unlikely ally is pitching in. Rampant foreclosures and abandoned homes with backyard pools have become a nuisance, but bats are coming to the rescue!

The fast-flying mammals that may give you the heebie-jeebies spend every night eating up mosquitoes that can bite and make you sick.

Mosquitoes Move in Next Door

Unmaintained pools can be a real problem and a serious health risk. While some water evaporates into the hot desert air, the remaining water becomes a stagnant breeding ground for mosquitoes.

At the height of the housing downturn, there were 14,000 complaints in the Phoenix-metro area about pools with stagnant water, also known as “green pools.”

Maricopa County Environmental Services staff worked around the clock trying to combat the problematic pools. Increased anxiety over mosquitoes carrying West Nile Virus has added urgency to the problem.

This year alone, more than 20 cases of West Nile Virus have been reported in Maricopa County.

Nature to the Rescue

Bats are mosquito eating machines. In one hour, they can eat up to 1,200 of the pesky bugs.

“Over the past four years we have been able to address a good number of abandoned pools in the area,” says David Guerrieri, supervisor with the Maricopa County Environmental Services department. “But any help we can get from nature is certainly appreciated.”

Arizona’s diverse population of bats—28 of the United State’s 40 species live here—play a key role in keeping insect populations in check. But despite the bug buffet surrounding abandoned pools, bats are experiencing dramatic declines.

Addressing Vanishing Bats

Bats are essential human allies. But, they are in trouble in Arizona and around the world as disease and development stifle their populations. In fact, scientists say this is one of the worst wildlife declines this century.

“Many of the Conservancy’s projects in Arizona help bats” says Rob Marshall, director of science for the Conservancy in Arizona. “Just like birds, animals and people, bats rely on stable habitats to live in and reliable water sources to drink.”

Bats can be spotted at dusk on Conservancy preserves, in forests and throughout the state.

A New Way to Celebrate Halloween

As we celebrate Halloween this year, consider the bat as more than the holiday’s iconic symbol. They’re an invaluable natural resource, playing a role in keeping you from itchy, annoying mosquito bites that can make you sick.

You can take it a step further and protect your family from mosquitoes by building a bat house in your backyard. Installing a bat house is a great way to naturally reduce lawn and garden pests.

To improve your success at attracting bats to your bat house remember to keep the following in mind:

  • Temperature is a critical factor in roost selection. In the hottest areas of Arizona, bat houses should be on north- or east-facing structures where they will receive morning sun, but be shaded from direct sun in the afternoon.
  • Mount bat houses on the side of a building or on a pole at least 12 feet above ground (higher is better). Houses mounted on trees are usually not successful.
  • Remember bats like a clear swoop zone to exit and enter their roost, so avoid placing the house in an area with obstacles, such as tree branches.
  • Do not mount the bat house close to bright lights.
  • In Arizona, bat houses should be painted a light color to reflect heat.



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