Unsung heroes in the fight against Lyme Disease

My first up-close encounter with a possum was one evening years ago when I went into the feed room to get feed for our horses. I was used to seeing these hairy, grayish animals flattened on the road, their lives abruptly and unceremoniously ended while out on a nightly prowl, but I was not expecting to see this 18-inch-long freeloader wedged under the feed bin. A closer look prompted a couple of low hisses from the hapless creature, but it didn’t move—it was probably as surprised to see me as I was to see it! I had unknowingly put out the welcome mat for this visitor when I forgot to close the feed room door that morning. I got my feed and left the door open, hoping it would take its leave the same way.

Photo: Google images

The oft-maligned opossum is actually a fascinating creature that suffers from an image problem. Frequently perceived as a dim-witted, rat-like scavenger whose most impressive trick is mimicking roadkill, this creature has one spectacular virtue that just might transform the aversion of some for this odd, waddling mammal into at least tolerance.

Turns out possums are the unsung heroes in the fight against Lyme Disease. Large numbers of the ticks that carry the Lyme disease bacteria are found on mice, shrews, squirrels, and chipmunks, but not so with the opossum. Researchers at the Cary Institute of Ecosystem Studies in Millbrook, NY found out why. Several opossums were placed in cages and covered with ticks. The researchers waited for the biting ticks to jump off and counted how many escaped the mammal’s voracious appetite. The opossums ended up grooming off and eating over 95 percent of the ticks that landed on them. Experts estimate that a single possum can eat as many as 5,000 ticks in one season!

Typically, possums go about their business so quietly that you won’t even know they’re around. What should you do if you do happen to encounter a opossum? Absolutely nothing! Possums seldom stay in one place for more than a few nights, so fears of them “moving in” are unfounded. Just watch from a distance and enjoy one of nature’s most unusual and beneficial wildlife species.

In our midst

Despite their fear of humans, some birds choose to rear their young right outside our door

For the past several years, Eastern phoebes have chosen to nest on our porch. This spring, they built their mud, moss, and grass nest on a ledge above the door. Thinking it was not a good place because of all the foot traffic, I removed the nest, only to have it reappear a few days later, so I let it stay. Mama phoebe would find out soon enough what it’s like when three barking dogs come charging out the door to defend us against any real or imagined four-legged invader that might happen to venture into the yard.

Despite all the coming and going, mama sat on her eggs, flying off when the door opened, and returning a few minutes later. I grew more confident that she wasn’t going to bail on the eggs, and soon five sets of eyes could be seen peering over the rim of the nest.

Once the nestlings were big enough to watch the activity below, they seemed mildly entertained, taking it all in as if completely normal. Unfazed by the noise and commotion, even the time a fox ventured into the yard, setting the dogs into complete pandemonium, the phoebes grew and thrived. A few days later, they left the nest to start their new life.

Three days before leaving the nest

While the vast majority of passerines prefer to secrete themselves away from people during the nesting season, others seem to seek out a nesting site close to human activity. Every spring, phoebes, wrens, bluebirds, and other birds that normally shy away from people choose to raise their offspring literally at our doorstep, begging the question: If birds have a basic distrust of humans, why, then, do they take the risk of raising their family where we could easily cause them harm?

My answer came while reading a passage by author and professor emeritus of biology at the University of Vermont Bernd Heinrich in The Nesting Season. Heinrich wrote, “There are almost no Eastern phoebes in the wild nesting on cliffs as they did before human settlement. Phoebes have learned to take advantage of human protectors, and those birds that build their nests in human structures are spectacularly successful.”

What Heinrich was getting at was that some birds sense that their offspring will be safer if located close to human activity, areas their natural predators tend to avoid. Somehow they are able to temporarily overcome their fear of humans, and use their hosts as a sort of insurance policy against the predation of their nests.

What I was witnessing was simply an adaptation of wild critters to help them survive. While the activity going on around the phoebes was no doubt an annoyance, it seemed a simple trade-off: put up with the pesky humans (and their dogs) for a short time in return for a greater chance of survival for their offspring.

For the rest of the year, the phoebes will live out their lives in the woods and fields around us. We will see them winging their way across the meadows and hear their calls, but rarely will they venture as close as they did during the nesting season. But it’s a pretty sure bet that these same birds or their offspring will be our house guests next spring, once again seeking the protection of humans.

The underappreciated bat

Few animals in history have been so maligned as bats. For centuries, these flying mammals have been portrayed as blood-sucking, rabies-infested vermin, giving a bum rap to creatures that really do a lot of good. However, in the last couple of decades, thanks to the efforts of conservation groups and federal and state wildlife agencies, bats are being seen in a different light for the valuable role they play in the ecosystem.

As the primary predators of night-flying insects, bats are critical to reducing insect pest populations, including those pesky mosquitoes that take some of the fun out of being outdoors in the summer, and brought us such mosquito-borne diseases as West Nile and Zika virus, among others. Bats are part of a healthy ecosystem and integral to the balance of nature. Without bats, we would be overrun with insects and forced to use more pesticides, which can kill beneficial insects like bees, ladybugs, and dragonflies.

Every summer, a few little brown bats, probably males or unmated females, take up residence on our porch. We embrace these insect-eating machines that dine on mosquitoes, stink bugs, moths, beetles, and a host of other insect pests. In the fall, when the nights start getting colder and insects get hard to find, our furry visitors fly off to their winter hibernation site to wait for spring. 

Little brown bats roosting on our porch.

Because they have highly-specialized habitat requirements, bats do not adjust well to environmental changes. Adding to their vulnerability, they often live in very large colonies that can be wiped out in a single catastrophe. With many species suffering population declines due to loss of roosting habitat, loss of wetlands (which serve as insect-breeding grounds), pesticide poisoning, and disease, some are vulnerable to extinction. People can help bats by making their home landscape more bat-friendly. 

Welcoming bats will pay dividends in terms of organic pest control. These winged wonders play an important role in nature’s systems of checks and balances. In a healthy, diverse ecosystem, for every insect pest, there is a natural predator. One of these is the silent hunter of the night, the underappreciated bat.

HOW YOU CAN HELP BATS

As more and more land is gobbled up by development, bats are losing suitable habitat every day. People can help provide these useful creatures with places to live and feed by making a few adaptations to their landscape.

• Bats will live in man-made bat houses if they are placed on a south-facing structure away from natural predators. Bat houses and kits can be purchased online, or you can make your own with plans from Bat Conservation International (http://www.batcon.org/resources/getting-involved/bat-houses/build).
• Bats prefer habitat with a mix of open and wooded areas. Plant a variety of perennials, herbs, and night-blooming flowers like moonflower, datura, evening primrose, cleome, and nicotiana to lure nocturnal insects.
• Bats are drawn to aquatic areas, where insect populations tend to be greater. Adding a pond or wetland to your landscape will help to ensure lucrative foraging for bats.
• Avoid using pesticides that can harm non-target organisms such as bats and other wildlife.