.png)
NATURES’ NUANCES
Early May has finally showered us with measurable rain which is definitely needed for all our aquifers, plants and wildlife. However, within rain-filled barrels, trays and grasses lie pesky chiggers and mosquitoes breeding furiously from March through November in Central Texas.
One of nature's premier consumers of mosquitoes is the Order of the “Flying Hand,” or Chiroptera.
Beginning at dusk, four greatly elongated fingers spread wing membranes and take flight - usually to the nearest water source, where they dip their jaws for a drink. Then the hunt is on. These insectivores catch meals in their mouths or scoop them into their wings or interfemoral membrane (lying between the legs). This small unassuming, nocturnal creature is the only mammal capable of true flight - the bat.
This extraordinary creature is able to consume 1,000 mosquito- sized insects in one hour, including up to 15 different species of mosquitoes, 9 of which carry the dangerous West Nile virus.
Birds flap their wings up and down while bats “swim” through the air. Some bat species are very agile, similar to a Chimney Swift, with wing beats about 20 per second. They are able to feed as they fly and often turn somersaults as they take food from their wing membranes - unless the meal is supersized, when dining while “hanging out” is preferred. Legend has said that bats fly into a human’s hair seeking insects swarming above their heads. The well-furred bats may fly rather close, but are actually aiming for the insect swarm, not the head of hair.
Although bats' vision is rather poor, they are uniquely able to zero in on minute insects due to echolocation. Bats emit a series of continuous supersonic sounds through their nose or slightly opened mouth. The muscles in their ears contract and relax, blocking emitted sounds and receiving the echoes. This sound bounces off objects and is received by a bats’ specially designed ears, enabling them to determine the size, location, density, and movement of the target object.
There are at least 7 unique species of bats that exist in Texas. These include: Big Brown Bat, Brazilian free-tailed Bat (commonly known here as the Mexican free-tailed bat), Cave Myotis, Eastern Pipistrelle (smallest bat in the East), Evening Bat, Ghost-faced Bat, Hoary Bat (largest bat in the East) and the Red Bat. Most bats hibernate in winter, while others migrate to warmer climates up to 1,000 miles away. The Cave Myotis migrates between summer and winter quarters within a shorter range, selectively choosing caves, mines or buildings in the summer and only caves in the winter. One Cave Myotis was recorded hibernating at West Cave Preserve from November 2014 to February 2015, occupying small crevices in the ceiling.
Free-tailed bats have naked tails extending well beyond the edge of the interfemoral membrane, with half of the tail free, thus the given name. Their thumb and toe claws have double talons, unlike other species. The Brazilian Free-tailed Bat is actually the smallest free-tailed bat but the most common in the Southwest. With at least 100 million in the entire U.S., that makes it the most numerous mammal in the country.
This species lives in huge colonies in caves such as Bracken Cave Preserve, which has an estimated summer population of 15 to 20 million free-tails - the world’s largest bat colony. It is truly amazing to watch these bats simulating a tornado at sunset. They emerge with a great roar, forming dark clouds of bats streaming continuously for hours in order to consume vast quantities of migratory moth pests, small insects, ants, beetles and leafhoppers.
Bats save U.S. farmers around $23 billion annually by protecting crops from pests. One bat eats up to 1/3 of its own weight; 250,000 bats can eat 1/2 ton of insect pests. If you extend the math, bats from the Bracken Cave colony alone can consume 15,000 tons/night.
Another key purpose of bats is their ability to pollinate plants and disperse seeds throughout their range. Generally, people think of pollinators as butterflies, insects or birds. But because of their mastiff type faces (large for their body size) they are actually very efficient in collecting and distributing pollen.
A byproduct of bats, scat or guano, provides a beneficial natural use. During the Civil War the guano or bat droppings were used as a source for sodium nitrate for gunpowder and mined as a fertilizer through the 1940s. The guano remains an effective fertilizer for crops and a great addition to compost for yards when accessible.
Unfortunately, similar to other wildlife, bats numbers are declining rapidly. This is due to habitat loss such as fewer forests and caves for roosting or raising young and also fearful humans killing them when they take refuge in buildings. Whitenose syndrome, a deadly fungal disease, has also resulted in massive losses of bats since it was first identified in 2006.
So what can we as individuals do to help maintain or increase populations of bats? One option could be to provide artificial roosts in safe surroundings. Brazilian Free-tail bats are actually the most frequent bat house users, so this could be a key resource to assisting the survival of bats. One local boy scout from Troop #280, Benjamin Seshan, chose to complete his Eagle Project by building 2 bat houses in Dripping Springs Ranch Park (DSRP), especially since bats have been sighted within the main facility attempting to roost. Bat houses also have been built by one of the leading authorities, who founded Merlin Tuttle Bat Conservation (www.merlintuttle. org/ i- want- tohelp/) at West Cave Preserve.
Currently, there is a Master Naturalist Project which is deploying bat acoustic monitors throughout Hays County to help study their numbers. And a relatively new Citizen Scientist project will begin this summer to assist in observing and counting the bat numbers at Ranch Park. This will be held the first Friday of each month at the bat houses recently installed. Stay tuned for details on the DSRP - Nature Programs website.
