The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Thursday, September 25, 2008

How Does Hurricane Conditions Affect Our Wildlife?
by Ro Wauer

Hurricane Ike caused severe problems for people all along the upper Gulf Coast. We have all heard agonizing stories about Ike’s impact on human beings. But what about the wildlife, the birds, mammals, butterflies, and other creatures, that did not evacuate or go into a shelter of some sort? The answer is varied, depending upon a large set of circumstances. For instance, many of the more mobile species, such as birds and butterflies, were able to escape, either by flying away or floating away on the storm front. But many of all these creatures undoubtedly succumbed to Hurricane Ike.

Migrating northern birds probably did not enter the area of Ike’s influence, either by staying put out of danger or circling around the storm. Resident species had little choice, however. They simply hunkered down in some semi-protected location, not coming out until the storm passed them by. Mortality was undoubtedly significant. Some of hardest hit birds were some of the larger colonial roosting species such as the herons, egrets and gulls. But once the storm passed them by, the survivors probably did very well because most of those birds possess an omnivorous diet. They are ably to feed on almost any kind of carrion or a variety of dead and dying creatures. This probably is also true for any vultures and raptors that were present after the storm. In fact, there are records of increased numbers of raptors to an area following a storm.

Hummingbirds probably were hardest hit by the storm, for two reasons. First, they are tiny creatures that can be thrown about by heavy winds, and are very likely to be injured. Second, once the storm passes by, nectaring plants, on which hummingbirds depend, would be seriously diminished. And because flowering plants are probably affected by salt water from the storm, the surviving plants cannot flower for several days or weeks or even the following season. Often hummingbirds that do survival the storm perish soon afterwards unless they can find an adequate food supply. That is why hummingbird feeders, loaded with sugar water, are so important immediately after a storm.

And what about the mammals such as the deer, hogs, coyotes, and rodents? The same scenario for the birds might also apply to the mammals. Burrowing rodents could possibly survive in underground cavities that do not get flooded. But the larger mammals that were forced to face the water and wind might be less successful. Yet, most of these creatures are tough and are opportunists; that is how they are able to survive in this human-dominated society. And once the storm is past, the carnivores are likely to do very well. Deer that feed on plants may be more hard pressed, but they too are hardy creatures and are likely to make it even with a reduced food supply.

Butterflies are an interesting group of wildlife. There are records of butterflies suddenly appearing in a place they have never previously been reported, even a hundred miles or more from they known breeding grounds. Butterflies being so light weight and easily blown about, can ride thermals or storm fronts for amazing distances. Although many undoubtedly succumb to a storm, especially those adults that stay put, many escape simply by drifting away. And since most butterflies live only a couple weeks, and are replaced by newly emerging individuals, so long as the butterfly chrysalis survives, more butterflies can be present soon after a storm. But if their nectaring plants may be in short supply, emergence can be postponed.
The aftermath of major storms is a fascinating time for wildlife enthusiasts. Birds and butterflies can appear in out-of-range locations for days afterwards. That is why birders and butterfly enthusiasts keep a watchful eye out for surprise species.

Thursday, September 18, 2008

Snout Butterflies are Flying Once Again
by Ro Wauer

On a recent trip from Big Bend National Park, we encountered thousands of snouts flying across the highway, especially between Del Rio and San Antonio. The vehicle was plastered with snouts, almost so many on our window that it made it dangerous to see ahead. It was necessary to take our vehicle into town to get it washed before those bugs damaged the paint. And now the snouts are beginning to increase in our area, flying every which way.

Snout butterflies occur throughout Texas as well as west to southern California, east to central New England, and south into Mexico. They normally frequent woodland edges and stream courses and utilize hackberry plants to lay their pale green eggs. The tiny larvae, or caterpillars, which are dark green with yellow stripes, feed on hackberry leaves. They pupate before overwintering as adults in protected areas.

Some years they become super abundant. Raymond Neck, author of the 1996 book, “The Field Guide to Butterflies of Texas,” explains: “Certain climatic conditions, such as severe drought followed by heavy rains over a large area is southern Texas, produce massive amounts of leaves of foodplants. The leaf production allows a major buildup in population numbers of larvae and, subsequently, adults. The new generation of adults emerges at a time when the foodplants have been stripped of most of their leaves. The lack of leaves and the dense concentrations of adults trigger a migration involving masses of butterflies that easily number in the hundreds of thousands and even in the millions of individuals.” September 2008 is one of those periods.

Snout butterflies, more appropriately known as American snouts (Libytheana carinenta), are little butterflies, about one inch in length and with a wingspan of almost two inches. In flight they appear to be multicolored with brown, black and cream-colored wings. When perched with open wings their colors are obvious, as well as their distinct shape, including a long snout and square-tipped wings. Most often they perch with folded wings, perpendicular on a branch or on another surface, showing their gray to black to brown undersides. Their long snout is obvious. This unique feature makes them look very much like a leaf or twig and is said to have evolved in this butterfly family to provide them with wonderful camouflage.

Snouts truly are remarkable creatures, part of our native wildlife. However, there are times when they become so numerous along our roadways that they are less marvelous and become more of a pest.

Thursday, September 11, 2008

Starlings, The Norway Rats of the Bird World
by Ro Wauer

The non-native starling is one of the most aggressive and offensive bird in North America. It will readily replace many of our native cavity-nesting songbirds if given the opportunity, and as soon as the native songbird moves out it will stake a claim to the empty nest. An example of this comes from purple martins that may be driven out of its nesting box by the aggressive starlings, or as soon as the martin house is vacated starlings may move in to nest. It is extremely important that those of us with martin houses take the house down or fill the entry holes as soon as the martins are finished nesting. If not, the non-native starlings or non-native house sparrows will take over.

Starlings, or properly known as European starlings, were imported into the United States about 100 years ago by a New Yorker who decided it was a good idea to introduce all the birds mentioned in the plays of Shakespeare. The starling was one of those birds. About 80 individuals were imported from Great Britain. And progeny of that original introduction has spread all across the Continent, from the East Coast to the West Coast, north to Alaska, and throughout most of Mexico.

The key to their success is that it can take over niches previously filled by many other birds. They possess the behavior and structural advantages that make the takeovers possible. Not only are they strong and aggressive, but they readily fight with other birds, and they seldom loose. They are tough, bulky birds with a sharp beak that can easily dominate most other songbirds. Starlings have been found to usurp nests of even larger birds, such as flickers. If there are eggs in the coveted nest, the new tenant will discard them as well.

Although nesting starlings prefer natural cavities, they will take advantage of a wide assortment of sites. They have been found to nest in attic vents, drainpipes, culverts, and even mailboxes. Starlings collect grasses to place on the bottom of their nesting cavity, and they maintain an extremely clean nest until the young develop feathers. Afterwards they give up on housekeeping, and the nest often quickly fills with parasites. It has been said that starlings can tolerate an amazingly high number of parasites; another reason that starlings should not be allowed to take over martin houses.

Other adaptations that have helped starlings adapt include their slender, tapered bill and their vision. Starlings can probe for food underground in their hunt for grub, and they also take considerably food, such as spiders and a wide assortment of insects, on the surface by stabbing them with an open bill. Their vision is also rather unique in that each eye is independent so they can look forward, backward, up and down. This helps in searching for food as well as watching for predators.

In spite of their negative values, breeding starlings are rather gorgeous birds. Their speckled plumage contains numerous buff-white dots at the tip of the bird’s feathers. Europeans regarded these dots as stars, thus the bird’s common name. In spring, the plumage takes on an iridescent sheen, and the bill turns from a dull brown to bright yellow color. They are bulky birds with a short tail and rounded head. All and all, breeding birds are gorgeous creatures. It is too bad that they so impact on our native songbirds!

Thursday, September 04, 2008

A Sora in a Very Strange Location
by Ro Wauer

Finding a sora, a small water bird, in my backyard on a recent morning was a complete surprise. Actually it was a dead sora, probably killed by a raptor, and I may have frightened the predator away when I went out the back door. A red-shouldered hawk, that had been perched in an adjacent tree, flew away, screaming at me for sudden appearance. The dead sora was lying in the grass right next to our dragonfly pond. It probably had arrived during the nighttime and had just been killed by the hawk. On close inspection, I discovered that the sora was a juvenile bird, undoubtedly an early migrant that had become disoriented.

Soras are about robin-size, but with very different features. Adults are dark brown above with white streaks, with a ruddy cap and black face and throat, yellow bill, and grayish underparts with white belly bands. Juveniles lack the yellow bill and black face, and the throat is ruddy. Soras possess long greenish legs with long toes that allow them to walk on muddy surfaces. Their preferred habitats include both freshwater and saltwater marshes, and during migration they are often found in rice fields and other flooded agricultural sites. Their diet consists of a wide variety of aquatic insects, snails, and seeds.

As a member of the rail family, soras typically are shy creatures, staying within on nearby thick vegetation such as cattails. They occasionally venture out into open water where; they can swim and dive very well. Even youngsters right out of the nest can swim and dive. But birders seldom are able to get a really good look at soras because of their shy character. Yet, they are quite vocal, and a loud clap or “eek” sound often will solicit a response. They possess sharp, high-pitched “keek” or whistled “ker-wheer” calls. They also may give a descending whinny call, especially on their breeding grounds.

In Texas, soras occur primarily in migration and during the winter months. Nesting has been recorded within the coastal prairies, but that is a very rare occurrence. But from mid-August to mid-May they can be reasonably common at wetlands throughout the state. In fact, according to “Handbook of Texas Birds,” by Mark Lockwood and Brush Freeman, “there was an extraordinary count of up to 622 individuals from rice fields on the central coast on 14 October 1998.”

Birding the rice fields and similar open wetlands can produce a wide diversity of birds, from shorebirds to waders, ducks and rails. The rails usually are the least obvious of the birds because of their secretive behavior. But a careful observer could possible find three other rail species: clapper, king, and Virginia. Clapper rails prefer saltwater wetlands while king and Virginia rails prefer freshwater sites. Two additional rails occur in Texas. Black rails are resident along the upper and central coast, frequenting marine wetland areas such as that present along Magic Ridge near Indianola. Yellow rails occur only as a migrant and winter resident; most birders find their lifer within the upper coastal prairies such as at Anahuac National Wildlife Refuge.

Rails belong to the Raillidae Family that also includes coots, moorhens, and gallinules, all birds usually associated with wetlands. They all possess short tails and short rounded wings, although all can fly very well and many migrate great distances. The tiny yellow rail, for example, over winters along the Gulf Coast but nests far to the north in the upper Great Lakes region and in Canada. Soras spend their winter months along the Gulf Coast, southern California and Arizona, and in Mexico, but nests all across the central United States and northwest almost to Alaska.

Who knows where the young sora found in my yard was fledged, but it was most welcome. It was my yard bird number 180.