Thursday, August 8, 2013

Bats Are In the News | Commentary by Evelyne Vandersande

evelynevandersande_mugBats are getting bad press lately because seven (to date in 2013) have been found in the Santa Clarita Valley that tested positive for rabies.


Rabies is around, independent of the bats, and we have more bats that you can imagine. But it’s a good reminder for you to have your pets vaccinated for rabies. (It is the law.) If you have found any dead animal on your property, call Animal Care and Control at 661-257-3191, and they will pick up the body safely and free of charge.


If you see a bat on the ground, it is a dead bat – or a bat that will soon be killed by a predator. Bats cannot take off like a bird; they need a little bit of air under their wings to be able to fly. They can crawl onto a bush, and that would be enough height for them to manage to fly, but their feet are weak and they cannot walk very well.


Mexican free-tailed bat

Mexican free-tailed bat, like those in the SCV.


There is so much to learn about bats, I am not sure where to start. But right away, I will give you a good place to go observe them. It is Carlsbad in New Mexico. Perhaps you want to take a summer trip there? Hundreds of bats gather there, and they have two programs to observe them: a bat flight breakfast and an evening program. Call the park at 575-785-3012, or Google-search “Carlsbad Caverns.”


The most common bat in our valley is the Mexican free-tailed bat.


Many people do not believe we have bats in Santa Clarita and say they have never seen them. Most of the time, they think they are seeing a bird in the evening, but you need to observe a bit more carefully and you will see that no bird has a flight pattern so crazy, erratic, full of energy – or it would have to be a very drunk bird! Bats use this zigzag flying pattern when they hunt because they are catching insects in the air.


When they migrate, they fly in a straight line; otherwise the trip would extremely long. During migration, they have been observed flying 25 to 47 mph, but they also have been clocked flying 60 mph using tail winds. Mexican free-tailed bats can also fly at very high altitude, over 10,000 feet, higher than any other bats. They have long and narrow wings that are well adapted for flight. Even their short fur and their ear orientation makes them more aerodynamic.


In our valley, bats take up residence under the bridges over the Santa Clara River; they like the Spanish-style roofs to roost under; cavities in trees; and the many little holes under roofs.


evebat080713cThey seem to like the oak, eucalyptus and pine trees in my neighborhood. I guess many of those large trees probably have little cavities where they can roost. They do not roost in caves in Placerita Canyon, but they do so in the Vasquez Rocks Natural Area.


Bats are insectivores, and they hunt their prey using echolocation. They eat moths, beetles, dragonflies, flies, true bugs, wasps and flying ants.  They catch the insects in flight in large numbers, so they are beneficial to the environment. One bat can eat 200 to 600 insects in a single night.


They are efficient pollinators, and while we do not have sugar cane plantations in Santa Clarita, I could not resist telling you that the bat was chosen as the logo for Bacardi rum, in recognition of their role as pollinators and consumers of the insects that were damaging the crops.


It is a good choice, as the Cuban and Spanish cultures recognize the bat as a symbol of good health, good fortune and family unity.


Mexican free-tailed bats are also known as the “guano bats” for the enormous amounts of droppings they produce. If they are in large concentrations like at Carlsbad Caverns, it is good business to collect this natural fertilizer. From 1903 to 1923, at least 100,000 tons were removed from there and sold to the fruit growers.


Even with our mild climate, Mexican free-tailed bats migrate to Mexico in the fall, returning here around May. They are active the whole year around and do not hibernate.


evebat080713aThey mate just before they fly back north, and by summer, they separate into bachelor colonies and nursery colonies. Gestation lasts for 90 days, and each female has one pup in June. Mom gives birth while clinging to the roost with both thumbs and both feet.


That gave me pause to think when I read that … For about one hour after birth, the baby remains attached to the mom by the umbilical cord while Mom licks the baby, sniffs it all over, and they learn each other’s smell and sound. After that, Mom and pup will always be able to find each other, even in a large cave where many pups are gathered. They recognize each other mostly by smell, and when Mom comes back to feed the pup, she always touches the top of its head with her muzzle, smelling it and exchanging vocalizations for one or two minutes each time.


The pup learns to stay attached to the side of the roost with his feet, hands and teeth. The mother feeds the pup with her milk, giving about a quarter of her body weight in one day. The milk is rich and the pup grows fast. They learn to fly when they are 4 to 5 weeks old, and they are weaned at five to six weeks.


Even if Mexican free-tailed bats can be found all over the country in large numbers, they are still a threatened species. They have to face the problems of finding a roost where they can have their young, and many of those sites are disappearing: old empty buildings, mine shafts, etc.


Their predators are many: red-tailed hawks, American kestrels, great horned owls, barn owls, opossums, striped skunks, raccoons and snakes, if they fall to the ground. Their population is declining. Because they eat so many insects, one huge problem is the wide-spread use of insecticides, which results in reduced reproductive success and death for the bats.


To me, bats are a great part of warm summer evenings. I first saw them as a child on vacation at my grandma’s in the country, where I was allowed to run outside in the dark. It always was an exciting and slightly scary sight as they would swoop so close to my head. Later on, in summertime at the last Placerita Canyon Nature Center party in June, when we could see them in the parking lot, saying goodbye to our friends for the summer, and now when I see them in my back yard – it’s a warm summer evening’s excitement to savor before the first cool hint of fall touches the air.


Keep looking. They are around. Now you’ll know them when you see them.


 


Evelyne Vandersande has been a docent at the Placerita Canyon Nature Center for 27 years. She lives in Newhall.


 


 



Bats Are In the News | Commentary by Evelyne Vandersande