The Nature Writers of Texas

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

Sunday, June 20, 2004

Butterflies and Host Plants
Ro Wauer, June 20, 2004, The Victoria Advocate, © 2004

A recent trip to Aransas National Wildlife to survey butterflies was a good reminder how some butterfly species can only be found during a brief period of time each year when their larvae (caterpillar) foodplants are available. At Aransas, a few soapberry trees were in flower at the entrance to the Rail Trail, and several of the creamy flower clusters contained feeding soapberry hairstreaks. This hairstreak can occur throughout most of Texas, although its range excludes most of South Texas, but it flies only for a few weeks each May and June.

There are several other butterflies that fly only during brief periods, but most are not so dependent upon obtaining their food from their flowering hostplant. The majority of butterflies feed on nectar that they obtain from a wide variety of flowering plants. Yet each species has one to several larval foodplants on which it lays eggs. The larvae will then consume that plant before developing a chrysalis from where the adult will eventually emerge. Larval foodplant examples include dill for black swallowtails, pipevines for pipevine swallowtails, mistletoe for great purple hairstreaks, passion vines for gulf fritillaries, Texas thistle for painted ladies, and hackberrys for snouts the emperors.

One of the more interesting host-specific butterflies is the yucca giant-skipper that lays its eggs on the tip of yucca plants. These large skippers fly only during springtime but never feed on nectar; males obtain nutrients by sipping mud. The eggs hatch within a few days and the larvae build a silk "nest" among the leaf tips where the larvae live, feed on the leaves, and grow. They eventually tunnel into the yucca roots and construct a dung-covered silk chimney-like tube near the yucca base. The larvae are able to hibernate. In spring they emerge from the silken tube as an adult giant-skipper.

Butterfly watchers learn that knowing the proper foodplants help considerably for finding butterflies. Although species like the gray hairstreak can use an enormous variety of plants, the reason that species is so widespread and common all across North America. And painted ladies are also widespread; they are commonplace all through Europe and Central and South America. All species must find their essential foodplant in order to reproduce. Milkweeds are good examples, for migrating monarchs can only survival their springtime journeys if they reproduce along the way; monarchs feed on milkweeds and milkweeds also serve as their larval foodplants.

A number of other larval foodplants in the Gulf Coastal Area of Texas include mustards for checkered whites, kidneywood for southern dogface, sennas for large orange sulphurs and sleepy oranges, blackbrush for coyote cloudywing, various oaks for Horace's cloudywing, mallows for checkered-skippers, sedges for dun skipper, and various grasses for clouded, fiery, eufala, and ocola skippers.

Anyone planning a butterfly garden, a hobby that is becoming increasingly popular, should always select their plantings to include some larval foodplants as well as flowering plants that are most likely to attract and feed the adults. The ten very best nectaring plants for South Texas, in order of importance, include crucita or mistflower (Eupatorium odoratum), cowpen daisy, tropical sage, mealy sage, frog-fruit, Texas palafoxia, palmleaf eupatorium, Mexican heather, weeping lantana, and gold lantana. A few other good nectaring plants include Mexican flamevine, milkweeds, pentas, skyflower, zexmenia, and zinnia. All of these plants and other suggestions are included in a brochure that Derek Muschalek and I wrote for the North American Butterfly Association, and available on the internet at www.naba.org.

One huge advantage of your own butterfly garden, whether it is an acre or more or simply a tiny one in a planter on your porch or deck, is that you can watch these marvelous creatures up close and personal.

Sunday, June 13, 2004

Barn Swallows are Widespread across Texas
Ro Wauer, June 13, 2004, The Victoria Advocate, © 2004

Of the eight regular North American swallows, none are as widespread and commonplace as the barn swallow. It can be found in every Texas county, including all those within the Coastal Bend where it usually is abundant from spring until late fall. And although most spend their winters south of the border, a few can usually be found wintering in South Texas every year.

Sometimes known simply as "swallow," its name throughout Europe, it is one of the easiest of the swallows to identify. It is a lovely bird with a long deeply forked tail, rusty throat, often a black upper chest band, and pale orange underparts. Juvenile birds possess white underparts. Its song is long and twittering, sometimes described as "energetic chattering," usually at different pitches. Kent Rylander, in his book, Behavior of Texas Birds, states that the male barn swallow's song rate is related to the bird's health. A female selects the healthiest male by listening to his song.

Barn swallows generally return to the same nesting site throughout their lifetime, but young birds do not return to their natal area to breed. They find other sites, often those that have been deserted or new sites altogether. Courtship occurs soon after the birds return to their nest sites. Pairs sit side by side on a perch, touch bills, rub their heads together, and preen each other's feathers. Then the will take off on a long, fast, but graceful flight, the male chasing the female. This flight can be extensive and can almost touch the ground to high overhead.
Another of the barn swallow's interesting characteristics is its seemingly preference for nest sites, often on man-made structures such as barns, houses, and the like. It builds an open nest plastered onto a wall, usually under the protection of an overhang. Construction materials include numerous pellets that it obtains from nearby mud puddles and plastered with bits of grass and heavily lined with feathers. Nests are constructed in seven to fourteen days, depending upon the availability of the season and availability of nesting material.

Four to seven eggs (usually 4 or 5) take 13 to 17 days to hatch, and the babies fledge in 18 to 23 days. Nesting pairs may occur in small colonies or they can be territorial, driving competitors away. But they join flocks of other barn swallows soon after the young are on their own. And migrants can occur in flocks of hundreds, and often in mixed flocks with several other swallow species. In spring and fall, when swallows are passing through, a large flock can take several minutes to pass.
A barn swallow diet is dominated by flying insects, but they can land on the ground to capture prey, or they occasionally feed on various berries and seeds. Swallows spend much of their time flying rapidly over croplands, pastures, lawns, and other places where they are likely to find food. The results are a marvelous display of pest control.
Of the five South Texas nesting swallows - purple martin and northern rough-winged, cliff, cave, and barn swallows - the barn is best known and most common.

Saturday, June 12, 2004

Learning the Birds
Today's Bird -- The Titmouse
Ruth Beasley, June 12, 2004, The Canadian Record, © 2004

Today's bird doesn't get talked about that much, at least not in polite conversation. It may be because this bird's name is somewhat, well, problematic. The bird in question is the Titmouse, and as far as names go, it is clearly on the awkward side. The most common nickname I could find is tomtit, and that's not much better.

But what are we to do? It is all well and good for some lofty ornithologist to go around saying words like "Titmouse", but for us ordinary folks it takes a bit of courage.

I plan to get on with it, though, since a Titmouse is a bird worth knowing about and so worth mentioning, however awkwardly. Still, it does seem that every time I say that name, I hear the sound of adolescent giggles.

To be fair, the name refers to an old German word for anything small and dainty, whether object, animal, or person --- in particular, a small German girl.

The Titmouse family includes Chickadees, Bushtits, and Verdin. All are small congenial acrobatic birds with strong legs and cone-shaped bills.

But Chickadees and Bushtits have heads as round as Charley Brown's, while a Titmouse head has a point. The silhouette of a Titmouse is a bit like a Cardinal, except that a Cardinal can be said to wear a crest. A Titmouse wears more of a dunce cap than a crest, and the bird is, in every way, more comical and less grand.

In fact, a Titmouse is a bird so cute, you almost hate to mention it. They are the kind of adorable birds only a real man could love. At about 6 inches, they're a bit larger than the chickadees and goldfinches in whose company they are often found.

There are several styles: there are Tufted, Bridled, Black-Crested, and Plain. The Plain Titmouse is a smooth gray overall, unadorned but for that pointed head.

The Tufted Titmouse is all dressed up, with a rust-colored vest thrown open over an impeccable white shirt, and a formal slate-gray topcoat with a black lining. His tuft is gray, but he has a spot of black right in the middle of his forehead.

Black-Crested Titmice have a black crest, but are otherwise dressed like the tufteds, in a suit of tasteful gray. In Texas, the Black-Crested Titmice are found so frequently in Palo Duro Canyon that Paloduro was briefly their official name.

Titmice do not migrate in an ordinary year, and in winter they comb the trees for hibernating insects and hidden insect eggs. They do like seeds and berries too, and can be readily drawn to a feeder.

In winter they nest in abandoned Woodpecker holes, crowding together for warmth. If they enjoy these winter homes, they'll revamp them into nurseries in the spring.

The mortality rate of Titmice is high --- to survive they lay two large broods every year. Many a small flock of Titmice is made up of one great big extended family: two parents and several sets of siblings, keeping close together in cold weather.

So keep your eyes open for gregarious pointy-headed birds that are exceedingly cute. And practice saying that name with a straight face and no giggling, for there are many awkward names in Bird World to master. There's a Wren-Tit, a Siberian Tit, and the Great Tit, too (which proves it's not always easy to talk about the birds!)

Sunday, June 06, 2004

Breeding Bird Surveys
Ro Wauer, June 6, 2004, The Victoria Advocate, © 2004

Last week I completed my annual breeding bird survey, one of 140 surveys conducted annually in Texas, and one of 2,444 run throughout the United States each year. Adding the 391 surveys conducted in Canada brings the total to 2,835. My route, known as "Yoakum," number 83-314, produced 718 birds of 55 species this year, with about the same numbers that I recorded in previous years. High species included 129 northern cardinals, 61 black vultures, 48 painted buntings, 44 American crows, 33 tufted titmice, 32 Carolina chickadees, 28 Carolina wrens, and 27 northern mockingbirds.

Some of the less abundant species, however, were somewhat different than usual. Finding eleven wood storks, four white-tailed kites, and two roadrunners were somewhat surprising, as these birds are rarely recorded on the Yoakum survey. The wood storks were of special interest, as these huge black-and-white waders nest in coastal Mexico and wander north into Texas afterwards. Five northern bobwhites were more than usual, good evidence of a good year for bobwhites. But fewer loggerhead shrikes, dickcissels, and lark sparrows suggests poor years for those species. Of course, local weather conditions influence breeding birds to a significant degree. Droughts and greater than normal rainfall seriously affect a bird's nesting potential. That is why it is important when accessing bird populations in any area to examine long-term records rather than those for a single or even several years.

Breeding Bird Surveys (BBS) are designed for long-term data-gather. Under the coordination of the U.S. Fish and Wildlife Service and with state coordinators, BBS have been undertaken in some areas for 30 years. Victoria's own Brent Ortego, Texas Parks and Wildlife Department, is the Texas State coordinator who assigns routes and provides advice as needed. The long-term database produced from the BBS provides researchers and other interested people with the very best understanding of the changes in bird numbers available anywhere. Anyone can query the database at www.mp2-pwrc.usgs.gov/bbs/.

The surveys are all conducted with the same protocol. Each must begin at 6am, about the time when songbirds are most active. Each route is 25 miles in length, with stops every half-mile, resulting in 50 stops. Each stop is three minutes in duration, during which time the counter records on a tally sheet every bird detected visually or audibly. Oftentimes the first few stops are so full of morning songs that it can be difficult to sort through them all, and by the time the last 20 or so stops are made birdsong is usually only a shadow of what it was at the start of the route. I have found that visual observations, especially early in the mornings, are less important than the audible clues. But as the day begins to warm up and the vultures and hawks begin to fly, visual observations become important as well.

My Yoakum route runs from the junction of Kaiser-Adams Roads and SH 3010, just south of Yoakum, westward toward Cuero, Lockhart Cemetery Road across SH 183, past the prison onto SH 766, and branching northwest onto a county road toward Cheapside. I mention my route because a number of people pass me standing on the roadside, trying to ignore them, while watching and listening for what birds can be detected during each three-minute period. Occasionally someone will stop and ask if I need assistance, or some folks just stop to visit. I do appreciate those who stop to ask if I need help. Most folks, when they discover that I am doing a "breeding bird survey" in their neighborhood, just look at me as if they are uncertain about my intentions. Most understand and go on, leaving me to enjoy the morning and what birds the day may provide. BBSs are fun and most worthwhile!