Owl eyes closeup

The great horned owl’s eyes don’t move in their sockets, so the owl turns its head, sometimes as much as 270 degrees, to follow an object. (Susan Rachlin / USFWS)

Halloween. It’s probably your children’s (and maybe your) favorite day of the year with candy, costumes, pumpkins, scary movies and ominous images.

Among the ghosts and witches associated with things that go bump in the night are iconic creatures that because of their nocturnal nature or creepy-crawly character have been connected to dark forces. But when we clear away the cobwebs, we see just how useful these animals really are.


No other animal can be compared to the Earth’s only flying mammal. Like all mammals, bats have hair, bear live young and feed on milk. But unlike other mammals, fingers in a bat’s hand are elongated and connected by skin to form a wing.

Big-eared bat

Moths make up most of the endangered Virginia big-eared bat’s insect diet. (USFWS)

Some bats pollinate plants, ensuring the production of fruits that support local economies, as well as diverse animal populations. Fruit-eating bats in the tropics disperse seeds that are critical to restoring rainforests.Bat droppings, known as guano, are valuable as a rich natural fertilizer.

Many bat species prey on insects, including some of the most damaging agricultural pests. As primary predators of night-flying insects, bats help to control many of our most annoying pests.

To hunt at night, bats have developed a very efficient system to help them detect other objects. They produce sounds at high frequencies, and by listening to the echoes of these sounds, bats are able to discern objects. This is known as echolocation.

Tropical bats are active year-round, while those in temperate regions either hibernate or migrate during the winter. Many bats hibernate in caves and move to trees and buildings during summer. Some bats reside in caves year-round but have different summer and winter roosts.

Disturbing bats in a maternity colony or while they are hibernating poses a major danger for many bat species. White-nose syndrome, named for the white fungus that sometimes appears on hibernating bats, is the latest peril. White-nose syndrome causes wintering bats to fly outside when they need to be hibernating.

Ongoing research to increase bat survival includes biological treatments, vaccines to boost resistance and molecular and genetic tools. For the latest news about white-nose syndrome, research efforts and response plans, visit whitenosesyndrome.org.


With their nocturnal nature and ghostly calls, owls have been viewed as bad omens, messengers of misfortune or even death.

The reality is that owls are valuable predators. A single barn owl can eat more than a thousand mice in a year!

Owls stalk their prey without a sound. A modification in their feathers makes this possible. Their wings have downy fringes along the stiff flight feathers that muffle sound as an owl swoops in unnoticed.

Owls probably have the most acute hearing of any bird. They can hear sounds 10 times more faint than a person can detect. Several features make this possible. An owl has an extra large ear opening surrounded by deep, soft feathers that funnel sound. Furthermore, the feathers over the ear, the auriculars, are modified to be loose and airy. An owl’s entire face acts as an outer ear, with compact facial feathers funneling sound to the ears.

Owls have the largest eyes of all birds. Their eyes are so large that there is little room in their skulls for eye muscles. Thus, an owl turns its head, sometimes as much as 270 degrees, rather than moving its eyes, to follow an object.

Contrary to popular belief, owls have excellent vision in both daylight and at night. Their pupils are huge at night, letting in great quantities of light. In daytime, the pupils shrink to the size of a pinpoint. Their eyes are 10 times as light-sensitive as human eyes, due a concentration of light-sensitive rods in the retina.

Because they swallow their prey whole or nearly so, owls regurgitate indigestible parts like the bones, feathers or fur. They eject this matter in the form of a hard fur or feathered pellet. By dissecting pellets, scientists are able to determine just what types of animals an owl is eating. Even if they eat insects, the pellet will contain the hard exoskeletons.

Probably the most familiar owl is the great horned owl, noted for its large yellow eyes and large ear tufts. Its call is a series of low hoots. The eastern screech owl is a small (8 inches long) eared owl with color varying from rust to gray. Its call is a long quivering whistle.

Garden spider

A garden spider spends most of its time waiting for its prey to become trapped in its large, round web. (Andrew King / USFWS)

Of the earless owls, the barn owl is easily recognized by its light colors and heart-shaped face. Barn owls nest in barns, abandoned buildings and tree cavities. Its song is a long raspy screech.

The barred owl is recognized by a nine-hoot call that sounds like the phrase “who-cooks-for-you, who-cooks-for-you-all.”


As silly as it is, I have to admit that I am a bit of an arachnophobe. Over the years I’ve become accustomed to the small ones. I usually leave them alone. But the big ones, like the wolf spiders lurking in my compost bin, make my skin crawl.

Despite this irrational fear, most spiders are harmless to people and will not bite unless they are trapped or held.

As predators of many kinds of insects, spiders are important in controlling many insect pests in gardens or homes

Spiders are not insects; they belong to a group called arachnids. Unlike insects, they have eight legs, and lack wings and antennae. Most spiders have eight eyes, and all have a pair of claw-like fangs through which venom can be ejected. The tip of the abdomen has silk-spinning glands.

Some make webs to trap prey. Others, such as wolf spiders, actively pursue their prey.

They feed on a wide range of prey, including insects and other spiders. They produce venom to poison their quarry. Because spiders can only ingest liquids, digestive fluids are either injected or regurgitated into their prey.

Different types and textures of silk may be used to construct snares or webs, egg sacs, draglines and ballooning threads. Some spiders use web snares to trap prey, and all species construct a silk sac to deposit eggs. Silk is secreted as a liquid that hardens on contact with air.

Spiders lay eggs in a silken egg sac, often ball-shaped and hidden in the web or carried by the female.

For a spider to grow, it must shed its skin (molt) usually four to 12 times.

Most local spiders will not bite unless handled or confined and are not dangerous. The exception is the black widow spider. The female is about a half-inch long, black with a bright red hourglass shape on the belly. This spider’s bite is poisonous but it is more dangerous to children than adults. Should you believe you have been bitten by this spider, go to a doctor immediately for treatment.

Kathryn Reshetiloff, a Bay Journal columnist, is with the U.S. Fish and Wildlife Service’s Chesapeake Bay Field Office in Annapolis.

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