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Thursday, January 23, 2014

The Cunning Coyote

Coyote, Canis latrans

Although the coyote has been (and continues to be) one of the most persecuted mammals in human history, this is largely due to the common misconceptions and myths that surround the species.  Add the fact that they are a highly intelligent animal with keen senses of hearing, sight, and smell, and you can easily see why they are the subject of such scrutiny.

About the size of a small German shepherd, the coyote weighs an average of 25 to 40 pounds, with long, slender legs, a bushy tail with a black tip, and large ears that are held erect.  While its coat can vary, it is usually grey or buff-colored and its snout is long and slender.  A strong swimmer, the coyote characteristically runs with its tail down, instead of horizontally like foxes or up like wolves and dogs.  Primarily nocturnal and very opportunistic, coyotes will eat almost anything, but in Texas they prefer rabbits, rodents, and insects.  Because coyotes can utilize many different food sources and humans have all but exterminated its main predator, the wolf, coyotes have rapidly spread to all parts of the country, including urban and suburban areas.  


Considered monogamous with pairs living together for several years, coyotes are usually shy and elusive, but are frequently seen individually, in pairs, or in small groups, especially when near food.  A family group, more commonly known as a pack, consists of the parents, their pups, and, occasionally, the previous year's pups.  Male and female coyotes pair up, establish a territory, and breed from mid-January to early March.  Normally utilizing a natural cavity or a den dug by another mammal, they will make the necessary renovations by excavating multiple escape tunnels linked to the surface.  After a gestation period of 63 to 65 days, a litter of five to seven pups is born. During the weeks following the birth, the male will bring food to the family, but the female will not allow him inside the den. Coyotes normally may live from 10 to 12 years.

It is easy to get the impression that an area is overflowing with coyotes when one hears a family’s howls.  It reality, there are probably only 2-6 individuals in a pack!  While some people may find it a bit unnerving, coyotes use howling as a means of communication to tell non-family members to stay out of their territory, to locate one another within their territory, to distract other coyotes away from young pups, and as a means for older pups to practice mimicking their parents.

Due to misconceptions and fears about coyotes, many people don't recognize the beneficial aspects that coyotes contribute to our ecosystem. Predators, such as the coyote, serve a valuable function in keeping prey species in balance with their habitat. Populations of small animals, such as rodents and insects, could increase out of control without predators. Coyotes can reduce the number of small animals that homeowners and gardeners consider as pests. While coyotes may change ecological balances of predator and prey species somewhat, they will not eliminate other species from the environment. Many scavenger animals, such as foxes and vultures, benefit from coyote predation on other animals through increased food availability from leftover carcasses.

Coyotes are naturally afraid of people and their presence alone is not a cause for concern, though they can become habituated to rely on human-related sources of food.  Simple steps you can take to peacefully coexist with them include keeping your garbage and recycling inside and secure until the morning of pickup, closing off crawlspaces under porches and decks, feeding your pets indoors, keeping your pets indoors at night (especially cats and small dogs), and educating your neighbors to do the same.

Like all wild animals, coyotes have a right to inhabit our wild places, including the preserves that border our suburban homes.  If you do your part to help strike a proactive balance between humans and these wild creatures and respect their right to exist, you may well be rewarded with a familial chorus of howls on a moonlit night!

Friday, January 10, 2014

Bag Ladies

Bagworm on Crepe Myrtle

While winter is the time of year when we hang man-made ornaments on our trees and shrubs to commemorate the holiday season, it is also the time of year when nature-made ornaments are most apparent in the landscape.  These ornaments are as widely unique as snowflakes, and their appearance varies with the bits and pieces of leaves, twigs, and bark fragments woven into silken bags in a shingle-like fashion.  They reveal themselves on the bare branches and limbs in winter, and they are created by female bagworms.

Bagworm on Anacacho Orchid Tree

Members of the Psychidae family, there are about 1,350 species of bagworms worldwide, also commonly known as bagworm moths or bagmoths. Although different bagworm species vary slightly in habits and life cycle, bagworms spend the winter months in the egg stage sealed within the bags produced by females the previous fall.  

In late May to early June, very tiny caterpillars hatch, produce a silken strand by which the wind can carry them to new foliage (called 'ballooning'), and construct a tiny conical bag carried upright with them as they move.  During leaf-feeding, the caterpillars emerge from the top of the bag and hang onto the host plant with their legs, sometimes aided with a silken thread. The bottom of the bag remains open to allow fecal material (called ‘frass’) to pass out of the bag. 



By August or September, fully grown caterpillars have developed larger bags, and pupate within them.  Seven to 10 days later, the pupae of the male moths work their way out of the bottom of the bag, and emerge from their pupal skin.  These males have half-inch long clear wings, feathery antennae, hairy black bodies, and they spend their time seeking out a female to mate.  Females, on the other hand, are immobile and stay in the larval stage, do not develop into moths, and remain inside the bags. After mating, the females produce a clutch of 500 to 1000 eggs inside their bodies and then die.    



Bagworm on Juniper

Bags vary in size, up to 2 inches long and about a half inch wide, and are spindle-shaped.  They can be quite ornamental, covered in a somewhat patterned array of bits and pieces of plant matter.  A wide range of broadleaf and evergreen trees and shrubs serve as hosts for bagworm species, including juniper, cedar elm, bald cypress, live oak, persimmon, sumac, sycamore, willow, yaupon, and native fruit and nut trees.  

Since these bags are composed of silk and plant materials, they are naturally camouflaged from predators such as birds and other insects.  While birds can eat the egg-laden bodies of female bagworms after they have died, the eggs are very hard-shelled and can pass through the bird's digestive system unharmed.  This represents yet another way to disperse bagworm species over a wide-ranging area, and helps in creating a whole new generation of bag ladies!