Blue Ghost Fireflies

It's that season again--the season of Blue Ghost Fireflies. Here in the Southern Appalachians, we are lucky to live alongside one (or two) of nature's real wonders. Both Blue Ghost Fireflies and Synchronous Fireflies can be found here and nowhere else in the world. 

Blue Ghosts are tiny insects, about the size of a rice grain. They glow gently and constantly as they hover just about the forest floor. Many people have described how their glow is almost eerie, leaving the viewer wondering whether they are really seeing something natural or perhaps imagining it all.  But thousands of people come to see if for themselves, from mid May until mid June throughout the Southern Appalachians. 

Only the male Blue Ghosts can fly. The females are flightless and remain buried in the leaf litter of the forest floor until they are ready to mate with a male. Then they climb up onto a twig or bit of decaying leaf that sticks up from the forest floor and they glow, too, waiting for a male to find them. The Blue Ghosts are visible to us during this season because they are using their glows to "talk" with each other. We are able to oversee (overhear?) that communication. 

A couple of wonderful articles have come out recently about the Blue Ghosts because so many people have become interested in the phenomenon. Perhaps because they occur nowhere else on Earth, or maybe because of the sheer beauty of their display, the Blue Ghosts have become a sight not to be missed. Raleigh's News and Observer, Charlotte's Observer, and Asheville's Citizens-Times have all run articles recently. Brevard's own Digital Media Productions is putting together a video.

Chattering Chipmunks

I was just talking with the librarians at Brevard College and they asked me how all the cold weather was affecting animals that hibernate during winter months. Their questions reminded me that just after the recent period of very cold weather, I saw a chipmunk scurrying about. I was surprised to see the animal because Chipmunks hibernate in winter. Their normal hibernation pattern, however,  is to spend short periods of time awake and foraging for food. Here is more information from the National Wildlife Federation. 

Chipmunks are ground squirrels, and while they often climb trees, they build their nests underground. Each Chipmunk builds its own burrow system as an adult and occupies it for the rest of its life. Chipmunks occur up and down the Appalachians, but not in the coastal plains from North Carolina to Georgia, and are most common in forested locations. Their small, brown bodies are about six inches in length, with tails three inches long, which they hold nearly upright as they dash about. Along each side, they have a thin white “racing” stripe surrounded by black stripes above and below it.

The reason that I saw the chipmunk when I did was probably because it was out looking for more food, such as spilled sunflower seeds from my "bird" feeder. When food is plentiful, they cache the surplus underground in their tunnel system.  Acorns or other seeds that are not consumed, either because a Chipmunk stored an excess or because it did not survive the winter season, may sprout from these caches.

In the wintertime, Chipmunks are quiet, with no energy to waste on noise-making. But in spring, they make several calls to advertise their territory. One is a high-pitched, short "chip" that also functions as a warning call when the Chipmunk spots a predator. The other very common call is a repetitive "munk, munk, munk." Native Americans named the animal for its call. 

The very cold weather may have awakened the animal in its burrow and it ate more food to keep warm (or keep its teeth from chattering). Perhaps it was out gathering food to replace its cache, or it might have been collecting more dead leaves to increase the insulation in its burrow. I hope it found enough, because cold weather is returning for a few more days!

Thanks, Nancy and Marie, for asking about hibernation!

Halloween and Bats

While visiting the magnificent Biltmore House in Asheville, N.C., I had a close look at some of the gargoyles adorning the cornices. They look like bats! Gargoyles are almost always winged, with long ears, contorted faces, and fangs. Bats have prominent ears because their hearing is their most important sense. The weird faces, with fleshy outgrowths around the mouth and nose, help to focus echolocation sounds. Bat eyes are tiny and their faces seemed pinched because they don’t need the additional input afforded by good eyes placed far apart in an open face. The bats’ spiky teeth are used to catch the insects they eat, and their mouths are usually open while they hunt. Conjure up a scary beast to put a little thrill into your Halloween: give it wings to fly silently through the night, elongated ears the better to hear you with, a wrinkled face with beady eyes and prominent nose, and stiletto teeth bared into a grimace. Now you have a bat, and all those scary features are simply the way it catches mosquitoes and moths by using its hearing. Our imaginations have run amok with one of nature’s many forms.

Too many people think of bats as filthy, rabid bloodsuckers whose sole desire is to fly into and tangle your hair--how far from the truth! We misapprehend them because their natural history is so different from our own. Bats are nocturnal, which may be the reason for their bad reputation, because nocturnal animals differ from diurnal animals in basic biology. Instead of using eyesight, bats use hearing to catch food, navigate, and locate other bats. In fact, blind bats can operate normally, but deaf bats are soon dead bats, for they can neither feed nor fly.

Echolocation is the primary sense of bats. As they fly, bats open their mouths and emit high-pitched shrieks that are beyond the range of our hearing. Their strangely elongated noses help focus the outgoing beams of sound, in the same way that a megaphone can focus a human voice and project it over a longer range. Their large ears receive the returning echoes from objects in their paths, concentrating the incoming sound waves as a cupped hand or ear trumpet will do. Bat brains use those echoes of sound to generate a picture of the world through which the bat is flying in the same way that our brains decipher signals from the retinas of our eyes. The images created by echolocation allow bats to “see” in the dark. They can avoid obstacles as thin as a single human hair, not to mention an entire head of hair.

Imagine imaging your environment with sound instead of sight. Some exceptional, blind people can echolocate by listening to the echoes of a tapping cane or clicks of their tongues. Using echolocation, they can locate and identify objects.

Bats are more active at night because their insect prey, mainly moths, beetles, and flies, is also more active at night.  Some tropical bats eat fruit, blood, fish, and other animals, but all Appalachian species are nocturnal insectivores. By flying at night, bats avoid competition with most birds for those tasty and nutritious insect morsels.

Bats are significant controls on insect populations because they must eat enormous quantities of food to power their high metabolisms. Their normal temperature is about 100ºF and their heart rate is 1000 beats per minute when flying. Most bats eat half their body weight in insects every night. For instance, a colony of endangered Gray Bats (Myotis grisescens) near Chattanooga, Tennessee is estimated to eat 220 tons of insects each summer from the area near that city. 

Because their insect prey is greatly reduced during winter, bats, like insectivorous birds, must either migrate to warmer locations abundant in insect food, or hibernate and slow their metabolism to a level that can be sustained by their fat reserves. Most Appalachian species hibernate in caves. During hibernation, their temperature drops to that of the hibernation site, usually around 50ºF. Their heart rate drops to fewer than 15 beats a minute. Even with such a slowed metabolism, bats lose about ¼ to ½ of their weight during hibernation, which lasts five or six months. 

Bats have been severely affected by White Nose Syndrome, which usually manifests itself during hibernation. It is a lethal fungus that grows on their bodies and damages the thin membranes of their wings. It also causes them to awaken during hibernation, which reduces their energy reserves so that they essentially starve to death. The disease has resulted in the death of over 5.7 million bats in eastern North America since it was first described in the winter of 2006.

Contrary to popular belief, bats are clean, not dirty, animals. Bats groom themselves like cats and are fastidious about cleaning their wings. Although it is correct that their roosting caves are often layered with their droppings, the guano builds up on the floor where we scrabble, not on the ceilings where they live. The ceilings are clean, providing secure toeholds for adult and young bats. Most hibernation caves have probably been used by bat colonies for thousands of years, for bats return to their home caves even if removed over 200 miles away. Humans have harvested the concentrated guano as a source of nitrogen for fertilizer and gunpowder. It is these human collectors of guano who become filthy, not the bats!

Although all Appalachian bats hibernate in caves, only some species use these caves in the summer months. Others spend the summer roosting during the daytime under bark or in tree cavities, and they readily accept bat houses.  The Little Brown Bat (Myotis lucifigus), a common eastern species, is one of the few bats that enters buildings. It spends the summer in maternity colonies made up of hundreds of mothers and young. If you encounter such a colony, rather than killing them all outright, please determine whether you can wait until the young can fly and the mothers and young leave on their own. Maternity colonies leave the building at the end of summer. If you wait to seal the building in the winter, the bats will be gone and will not be able to get back in the following summer.  

Bats usually give birth to only one offspring per year. The young are born early in the season, May or June, and can fly in two to five weeks after birth, depending on species. They are long-lived, especially for their size, with thirty years a common life span. In comparison, similar sized mice are reproductive within 35 days, can produce several litters every year, each with up to eleven young, and while they may live eight years in captivity, usually survive only one in the wild.

In the Appalachians, bats rarely carry rabies, but should never be picked up with bare hands. Like most frightened animals, they will bite if restrained, and any bat on the ground during daylight hours is not acting normally and may be ill. It is safe to say that if you are able to pick up a bat in the summertime, you shouldn’t. If you find a bat in the wintertime, it is hibernating; although you might be able to catch it, still you shouldn’t! Occasionally a bat becomes trapped in a house when searching for a roosting site. Open the windows and doors so that the bat can escape, but don’t panic. It will find a way out.

Can you help instead of harm these interesting animals that are fighting to survive the deadly White Nose disease?

Pumpkins: Fruit or Vegetable?

Overnight, a pumpkin patch sprang up on a church lawn across the street from Brevard College.  Dozens of people come through on a daily basis to pick out the perfect pumpkin to take home and turn into a jack-o'-lantern for Halloween. Pumpkins are the symbol of fall aren't they? In addition to jack-o'-lanterns, they can be converted to wonderful pies, soups, or roasted vegetables. So are they fruits or vegetables? Several people have asked me.

Fall is harvest time for humans and animals alike. While we thresh wheat, crack walnuts, pick pumpkins, make jelly, and can beans, animals are also busily gathering nature’s bounty. Lacking the ability to store food in cans or freezers, however, they mostly store it in their own bodies, as fat.  The fruits of fall are especially important in the diet of most animals.

Botanically speaking, “fruit” is a very broad term, encompassing more than we generally envision, because a fruit is the product of a pollinated flower, or a plant’s mature ovary, and therefore houses the seeds. Typical fruits are not only the fleshy fruits such as grapes, raspberries, or plums, but also those that are dry and woody or papery, such as milkweed pods, maple samaras, and oak acorns.

Anything with seeds inside is a botanical fruit, so peas, beans, tomatoes, squashes and, yes, pumpkins are technically considered fruits. Nutritionists, however, have a different opinion, considering sweet fruits as fruits and non-sweet or green fruits as vegetables. So take your pick--are you a botanist or nutritionist? Here is a fun blog about all those weird fruits.

The function of a fruit is to protect and disperse the seed, which is the plant’s offspring. Plants cannot move, and so their seed, like their pollen, must be moved for them, usually by wind or animals. Many familiar plants, such as dandelion, willows, and milkweeds, have small seeds with tufts of gossamer that are dispersed by wind. The fruits of tulip-trees and maples have little wings, and twirl like the blade of a helicopter as they are blown from the parent tree. Other fruits, such as stick-tights, beggar’s ticks, and cocklebur are covered with Velcro-like hooks that catch in the fur or feathers of animals. All these fruits are designed for passive or accidental transport, with structural modifications that enhance their ability to catch in fur or travel on the wind. And, yes, they are botanical fruits even though they are dry and papery. Here is more on technical fruits.

Other fruits are designed to actively attract animals for their seed dispersal. These fleshy fruits are edible fruits that enclose the seeds. The seeds are dispersed when animals feed on the fruits, either by swallowing the seed or discarding it after they have carried it somewhere else. Seeds that are swallowed must be small and protected so as to survive passage through a gut, but will be deposited with a nice load of fertilizer when the animal defecates. The germination of some seeds is actually enhanced by exposure to acid, such as that in a stomach, because it weakens the very tough seed coat.

Some seeds, however, are not designed to be eaten even if the flesh of the fruit is. Peaches, for instance, enclose the single seed per fruit with a very hard seed coat, and further protect it with a form of cyanide to make the seed inedible. Almonds, by the way, are close relatives of peaches in which a genetic mutation prevents cyanide production, rendering the seed edible.

The urban myth that swallowing an apple seed will kill you is based on fact, but blown out of proportion. Apple seeds produce cyanide when digested, but their seed coat is so impermeable that they pass through the digestive system undamaged and undigested. Swallowing a few whole apple seeds is, therefore, not a problem. Your body can even detoxify the small amount of cyanide released should a seed or two be damaged. Crushing a cupful of apple seeds (or peach seeds or cherry seeds) so that the protective seed coat is breached and then swallowing them could result in poisoning and is not a bet worth taking. Just stick to eating the fruit and leave the seeds alone--that is what the plant is hoping you will do!

Portions excerpted from my book, "Mountain Nature: A Seasonal Natural History of the Southern Appalachians."

Monarch Butterfly Migration

That most regal of butterflies, the monarch, is a common sight this time of year in the southern Appalachians and down through other southeastern states to Texas. They are heading south, to Mexico. Those of us along their migration route may see hundreds gliding silently overhead on any day between mid-September and mid-October.

It is nearly unimaginable that a creature so small, so fragile, should be able to fly to Mexico, but millions do. One monarch was tagged near Toronto, Canada, and was found, some weeks later, at a winter roost in Mexico. How long would it take you, a thousand times larger than a butterfly, to travel that same distance under your own power?

Monarchs accomplish this impressive feat by “fueling up” on the nectar of flowers.  Just a little sugary sap sends them on their way. Once they reach their destinations, they may not eat again until the next spring, and rely on a store of fat to sustain them. While the adults eat nectar from a variety of flowers, the caterpillars only eat milkweed. Milkweed grows naturally throughout much of North America, and planting milkweed is a way to increase Monarch numbers. It is best just to plant the milkweed and wait for Monarchs to show up rather than trying to raise them artificially, as this article from the New York Times explains.

Their wintering locations are unique habitats. Monarchs in the eastern part of North America winter in the mountains of Mexico. There the perfect combination of moist and cool, but not freezing conditions, allows the monarchs to slow their metabolism and survive without eating. They neither dry-out nor freeze. They usually huddle together in huge groups of hundreds of butterflies, and I’ve even seen them cluster together high in the tulip trees of the Southern Appalachian mountains on a cool migration evening.

Monarch numbers in their overwintering grounds have declined dramatically since 1990. The all-time low was in 2013, with both 2012 and 2014 also alarmingly low. The good news is that numbers started to inch back up in 2015 and 2016, but there is real concern that this year, after a slew of hurricanes, the numbers might drop again.

If you get a chance to look closely at a monarch, you can tell whether it is male or female. The sexes are patterned differently from each other, but the differences are subtle. The black veins on the hind wings of male butterflies are thinner than the veins of females. The male also has a black spot in the center of each hind-wing.

One of the best places to observe monarch migration is the Cherry Cove overlook on the Blue Ridge Parkway near mile marker 416.

To stand in the midst of a monarch migration, as they suddenly appear over the trees to the north, glide by within a few feet, then drop off the ridge to the treetops in the south, is an immersion into the natural world.

It’s worth the effort.

Male monarch butterfly. Note spots on thin veins of hindwing. Image may not be used without permission.

Screech Owls: What is that Scary Sound?

This morning, departing my home while it was still dark (about 7:00 AM), I heard the quavering, eerie call of a screech owl nearby. Screech owls are named not for the sound they make, but because of the sound some people make—a screech—when hearing them! Like the whinny of a demonic horse, the screech owl’s call modulates from a soft cry to a quavering sob. At the college where I teach, Brevard College in western North Carolina, a panicked student once claimed in a campus-wide email that a ghost followed him as he ran to his dormitory one September night, but I reassured the student body that he heard an owl instead.

Screech owls occur throughout the eastern two-thirds of the country. In the northern part of their range and throughout the Appalachians, they are most often reddish in color, but more southern owls are usually grey. They are not as shy as many of the other owls, and even occur in urban parks. They can be found in heavily forested areas as well as more open farm fields, near homes, and in neighborhoods that have mature trees.

Screech owls feed on mice and large insects. In turn, they may become food for the larger owls. Once a great horned owl or barred owl begins to hoot, the diminutive screech owls get quiet! As cavity-nesters, screech owls normally require hollow trees in which to nest. They will, however, readily use constructed boxes. By placing a nest box for them, you can attract a pair to your property. On evenings (or mornings) of early fall, you’ll be treated to the strange song of this small owl. Like me, you might smile with the knowledge that the population of mice living in your woodshed or garage will soon decrease while your owls raise their young.

Would you like more information? Much of this post was excerpted from my book Mountain Nature: A Seasonal Natural History of the Southern Appalachians. 

Leaf Color Change

Leaves have started to change here in the Southern Appalachians and I've had lots of questions about them, so here is an excerpt from Mountain Nature:

Leaves are green because they contain chlorophyll, which reflects green light while absorbing red and blue. We see the color of light that is reflected, not absorbed, by the leaf. By reflecting green light, however, the plant misses the valuable energy in that particular wavelength. They therefore trap as much as possible with additional, accessory pigments in the leaves, which capture some of the energy that chlorophyll misses and then transfer that energy to chlorophyll.

During spring and summer, the green of chlorophyll masks the colors of the accessory pigments, which include carotenoids and anthocyanin. The carotenoids are a group of closely related, common pigments that are present in most leaves (and carrots). They absorb green and blue light, reflecting orange and yellow. Anthocyanin also absorbs green and blue, but it reflects red. Thus, the carotenoids appear yellow or orange and anthocyanin red or purple.

On a fall day, the hills are alive with these vibrant colors. In the fall, so many leaves become various shades of yellow and red because the chlorophyll in those leaves breaks down, but the accessory pigments remain or are synthesized. As the days shorten, deciduous plants decrease the production of chlorophyll and it quickly disappears from their leaves. Since the accessory pigments are more stable, they persist and delight our eyes. In some cases, plants even produce more accessory pigments, especially anthocyanin. Once the green of chlorophyll is gone, these other colors shine through. 

Beautiful color appears every year at about the same time because the shortening days of fall signal the trees to begin the process of chlorophyll loss, but some years are more colorful than others. Good growing conditions during the summer (warm and wet) ensure that every leaf is packed with pigments and every tree is loaded with leaves, setting the stage for a spectacular show. During the peak period of leaf change, which is usually mid-October for the Southern Appalachians, several converging conditions produce a short, but extremely colorful season. A cold snap intensifies the color because cold temperatures break down chlorophyll quickly, thereby revealing the accessory pigments. Dry weather also intensifies the color because anthocyanin, present in sap, becomes more concentrated as the water in sap evaporates away. Excess water dilutes the sugary sap, as anyone knows who has tasted a watery, wet-weather cantaloupe. Finally, since sunlight also destroys chlorophyll, sunny weather intensifies the color. The best color show, therefore, occurs during a fall season that is dry, sunny, and cool at night. When these conditions are met, a short but spectacular show results, and it is the timing of the cold snap that determines when the show begins.

It is time to get outside and enjoy these brisk and colorful fall days. Enjoy!

Red maple leaves reabsorbing chlorophyll. Image may not be used without permission.