The Nature Writers of Texas

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

Sunday, May 27, 2007

Summer Tanager Numbers are on the Increase
by Ro Wauer

For the third year, summer tanagers are singing about my neighborhood at Mission Oaks, and on a recent breeding bird census between Schroeder and Mission Valley, I recorded three singing summer tanagers for the first time. The increased numbers of this charismatic species is most welcome, although why it has begun to frequent oak woodland areas of Victoria, DeWitt and Goliad counties are unknown. Although it's regular Texas breeding range includes most of the southern half of Texas, it usually prefers broadleaf woodlands like those found along the river floodplains instead of oak woodlands.

Male summer tanagers possess bright red plumage, except for the red-brown wings, while females are yellowish with a yellow-green back. Both sexes possess a rather large pale bill. And although they are not often easily seen, because of their habit of staying in the upper foliage of broadleaf trees, their songs and calls usually give them away. Summer tanager songs resemble that of the American robin, with a series of sweet, clear phases, but faster and more deliberate. And their call is a dry spit-a-chuck, pit-a-tuck, or pit-tuck. Sometimes they will give an extended series of calls.

The summer tanager male that is currently utilizing my yard may be the same individual that was present there during the previous two summers. My current yardbird is an adult male in full breeding plumage. The earlier individual had not yet developed full adult plumage, but was mottled with red and yellowish plumage. And I had the impression that it was a juvenile bird that had not yet found a mate, but working hard to attract a lady tanager. It sang loudly during most of May and June, but seemed to loose interest by mid-summer. And it spent considerable time at my birdbath, sitting in the water splashing itself with water. It stayed until September, and then disappeared, only to return the following April; easily recognized due to its unchanged plumage pattern.

Three other tanager species do occur regularly in Texas. The one that probably is best known is the scarlet tanager, a bird of the eastern forests, and is only an occasional migrant through South Texas. The western tanager is a bird of the western forests that is only rarely found in our area. The hepatic tanager is a bird of the Southwestern woodlands, fairly common in the Davis and Guadalupe mountains of West Texas. All are easy identified. The scarlet tanager male is also bright red, but it has coal black wings and a yellow bill; females are greenish-yellow with darker wings. The male western tanager is yellow and black with a red face and cap. The hepatic tanager male is a liver-red color with dark streaks on the wings and a black bill; females are yellowish with a black bill.

Tanagers primarily are tropical species that occur in the tropics, usually south of the United States. There are 28 tanager species in Mexico, and 216 species in South America. I suppose that we are fortunate to find a tiny percentage of that number in Texas. Our birds are neotropical species that come north to court and raise a family, but the majority returns to their tropical habitats soon afterwards where they spent most of their life.

Sunday, May 20, 2007

Fireflies, Nature's Evening Sparklers, Light Up the Night
by Ro Wauer

Every spring I am amazed all over again when the yard is suddenly filled with glowing lights from fireflies! I can't help but get excited for the umpteenth time about this marvelous work of nature. What child has not shared that amazement? Who has not captured one of these fascinating insects to watch it glow up close? Who has not wondered about these tiny creatures that turn our yards into miniature firefights?

The appearance of fireflies, sometimes known as "lightning bugs," are a sure sign that the winter months are behind us and summer is not far off. Fireflies appear only when the evening temperatures allow these cold-blooded insects, actually a soft-winged beetle of the Lampyridae family, to become active. The majority of the 2,000-plus members of the Lampyridae family (there are about 60 kinds in North America) possess luminous organs on their abdomens. They all are able to glow at will, usually starting at dusk and continuing until about midnight, generally as part of courtship to attract a mate.

Our fireflies are most numerous in humid yards and similar locations. The male firefly beetle is about 1/2 to 3/4 inch in length, with a pair of fairly long antennae and a yellowish abdomen. Females look more like larvae than beetles. Although both sexes glow, males are capable of shining about twice as bright as the females.

Each of the more than 2,000 forms of fireflies possesses a slightly different glow pattern or code of signals. The specific code is not so much the light (either color, brilliancy, or length) as it is the length of the intervals. Each species glows for a specific length of time, with a specific interval between glows. The males of some tropical fireflies actually flash in unison, and the tropical nights can actually brighten as if a great light is turned on and off. You can experiment with a penlight by copying the glow intervals to solicit a response.

The light itself is derived from the fatty tissue, called "luciferin," in the beetle's abdomen. The light is produced when the insect takes in air through tiny ducts. When the air reaches the luciferin, it is instantly oxidized, releasing the energy as cold light.

During the daytime, the lampyrid beetles and their larvae are usually found on vegetation where they prey on smaller insects and larvae, small arthropods, and snails that they find on old leaves or humus, or on the ground. But at dusk, the males begin their nocturnal signals, flashing their unique lights in such a way that their mates are soon flashing back. And the night becomes magical!

Sunday, May 06, 2007

Franklin’s Gull Were Plentiful This Spring
by Ro Wauer

Migrating gulls, especially those some distance from the coast, are unusual. So seeing several large flocks of gulls over Victoria and Mission Valley last week was rather special. These were Franklin's gull, a laughing gull look-alike. I first observed a flock of about 40 individuals flying over my Mission Valley yard on April 24, and then on April 26 I observed three large flocks, each with 50 to 80 individuals, passing over Victoria between Citizens Hospital and the Holiday Inn. All were heading in a northwestern direction, and moving rather fast, but steady, buoyant, and easy. It seemed they all were anxiously heading toward their ancestral nesting grounds in the northern portion of the Great Plains, perhaps in Montana or North Dakota or Saskatchewan or Manitoba in southern Canada.

The Franklin's gull is one of our most beautiful gulls, especially in spring when they are in breeding plumage. From afar, however, they looks very much like our common laughing gull, with a black head, slate grey back and wings, whitish undersides, and all red bill. Up close, however, a Franklin's gull's breast is tinged with pink, or a blushing rose color, and its wingtips possess a white bar across the wing tips. The laughing gull has an all white underside and all black wing tips.

While laughing gulls are commonplace along the Texas coast and often congregate in parking areas, a good place to find handouts, some distance inland, breeding birds very rarely stray too far away from the coast. Franklin's gulls, on the other hand, are prairie birds, nesting in large, compact colonies in marshy habitats along northern lakes. Nests usually are built in water two to three inches deep, but anchored to large platforms of dead reeds. Nests are constructed of coarse vegetation and lined with finer materials. The nesting materials are enhanced throughout the nesting period, and it sometimes is stolen from other unguarded nests.

Because of their habitat preferences they are sometimes known as "prairie pigeons." Although migrants often rest overnight in fields and feed on various insects and crustaceans, they rarely stay very long before continuing their northward journey. There also are numerous records of feeding gulls following agricultural machinery to feed on flushed insects. Nesting birds feed on a wide variety of materials from insects to crustaceans and earthworms, to small fish, snails, and even eggs and baby birds such as those of nearby nesting terns. They also have been found landing on a pelican's head and stealing fish from the bird's bill pouch. Their foraging methods vary from plunging into the water, dipping on the surface, swimming and wading, or walking or running across the ground to chase down prey.

Most Franklin's gull sightings in the Golden Crescent occur in mid-April to late May during the spring migration, but they rarely are seen to mid-June. Post-nesting southbound birds begin to appear in the Golden Crescent in late September, are most numerous in October and until mid-November, and there also are rare sightings during the winter months. The southbound birds continue south along the coastal plain of Mexico, cross over to the Pacific slope at the Isthmus of Tehuantepec, and continue south to their wintering grounds in Peru and Chile.

Seeing migrating gulls, especially those with a blushing rose breast, are truly special!