to WNS. WNS die-offs would severely restrict the ability of bats to consume night-flying insects, especially certain moths and beetles that are agricultural or forest pests. Bats eat a large variety of insects, including a few mosquitoes, some of which are public health pests, but there is little information on how much they control mosquitoes. A preliminary study in Missouri in 2010 looked at the role of gray bats in mosquito suppression.
Recent scientific papers estimated that bats contribute $961 million value each year to Missouri agriculture through insect control. Bats also contribute to forestry, but by an unknown amount. Some of our bats have been declining for decades, but each species has a somewhat different diet of insects. Our gray bats, though still endangered, have increased at some important bat caves because of improved protection by the Department and our partners. We estimate that Missouri’s nearly 800,00 gray bats consume 540 tons of insects per year, equal to about 223 billion “bugs.” Bats also have great scientific, educational, and aesthetic value to the public. To learn more, see www.batcon.org.
Bat Monitoring Methods…
The Department has monitored cave bat populations for more than 30 years, traditionally by visually counting several species of hibernating bats and estimating summer gray bat colonies by measuring their guano deposits. In the past decade we added new digital photography and infrared videography methods to our tools. From 2008 - 2011 we visited 15 gray bat caves, including 14 maternity caves and one major hibernaculum (winter hibernating location), taking more than 50 thermal-infrared videos and five guano (bat droppings) estimates. The average summer colony was about 42,000 bats, and there were more than 311,000 at the largest hibernating colony. Gray bats have abandoned many caves because of human disturbance and other factors, but their Missouri total is now generally stable or increasing. We know that there are mass migrations of grays in late summer from the Lake of the Ozarks area to Boone County and other counties. We are extending the thermal-infrared method to count bats in fall mating swarms or emerging from hibernation in the spring.
If You Should Find a Bat…
Please do not handle bats if you see them. WNS is not related to rabies, but if you find a bat on the ground it has a chance of being sick from something, such as rabies, which can be transmitted to you via a bite. There is a small but real risk that a downed bat could be rabid, and rabies is fatal to humans and mammals. Dead bats do not transmit rabies, but it is difficult to tell when a bat is actually dead, so please do not pick them up barehanded.
The public can help by reporting to the Department dead or dying bats on the ground or near caves in winter or spring, but we do not ask the public to go into caves or mines looking for bats. That can be very disturbing to the bats, especially when they are sick, hibernating or rearing young in summer. WNS is more likely to be found in late winter or early spring, and the bat would likely have a white, fuzzy fungal growth on the face, ears and wings, but not always.
We receive many calls in summer about bats in attics and houses, but those are not WNS related. All MDC offices have a reporting form for public reports of suspect bats, especially near caves. We are prepared to take those reports and send someone out to investigate certain cases, and possibly sample the bat if it is alive or freshly dead, but we cannot use old carcasses. We are ready to accept good close-up photos of WNS-suspect bats.
Calls about cave bats should go to Dr. Bill Elliott, 573-522-4115, ext 3194, Bill.Elliott@mdc.mo.gov and/or Shelly Colatskie, ext 3641, Shelly.Colatskie@mdc.mo.gov in the Resource Science Division, MDC Headquarters, PO BOX 180, Jefferson City, 65102. Calls about Indiana bats, forest and urban bats go to Resource Scientist Tony Elliott, Kirksville, 660-785-2424 ext 257, Anthony.Elliott@mdc.mo.gov.