The Nature Writers of Texas

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Sunday, November 06, 2005

Butterfly Numbers Peak in Early November
by Ro Wauer

For those of us who enjoy butterflies, early November days offer the highest numbers for the year. Butterflies present at this time of year usually include those species that have been present most of the season as well as strays from elsewhere, a few fall-only species, immigrants moving southward, and our lone migrant, the monarch. On a good sunny day in early November it is possible to find up to 50 species in our area.

The secret to finding butterflies is one or a few places to visit where nectaring plants attract and hold the passing butterflies. Even the travelers must stop occasionally to feed. So choice nectaring plants this time of year, such as flowering cowpen daisy, crucita, duranta, lantanas, Mexican heather, Mexican milkweed, palmleaf (Gregg's) eupatorium, penta, and tropical sage (my favorites), are the key. Especially crucitas (Eupatorium odoratum) are marvelous butterfly magnets in fall.

Besides the migrating monarchs, immigrants moving southward can make up a good number of a population. Most numerous of these are the painted ladies, the only butterfly species know to occur world-wide; red admiral, one that often stays around most of the winter months; and some of the larger sulphurs, such as cloudless and large orange sulphurs. Other wanderers, oftentimes strays from the south, can include rounded metalmark, julia heliconian, common mestra, and dorantes longtail.

Also in fall, a few temporary colonists, such as zebra heliconian and white peacock, can put in their appearance. Temporary colonists are a fascinating group of butterflies. They include species that cannot be expected on a regular basis, but only after a year when a stray female from another location happens upon a larval foodplant on which to lay eggs, the eggs or caterpillars overwinter, and adults appear the second year. They may breed again for another year, or several more years, before a colder winter occurs to destroy the population. An example is the zebra heliconian population that we had the last two years apparently got wiped out by last year’s Christmas Eve snowstorm. It is very likely, however, that additional strays will reach our area again this fall.

Butterfly populations usually are dominated by the full-time residents, although numbers of each species will vary, depending upon emergence cycles. But in general we can expect constant numbers of pipevine and giant swallowtails; little yellow; dainty sulphur; gray hairstreak; dusky-blue groundstreak; gulf fritillary; phaon crescent; common buckeye; goatweed leafwing; white-striped longtail; coyote cloudywing; long-tailed, sickle-winged, clouded, fiery, dun, eufala, and ocola skippers; common and tropical checkered-skippers; whirlabout; southern broken-dash; and sachem.

Many people first learning butterflies are surprised at the large number of the very small and tiny butterflies, species that are easily ignored in favor of the larger and showy species. Their small size also makes them difficulty to see. But with the advent of close-focusing binoculars, those can focus to six feet or less, even the smallest butterflies can be seen well enough to identify. And without seeing the butterfly's pattern, it is next to impossible to identify many of the smallest ones. For many of us watching butterflies, the smaller species, such as the hairstreaks, blues, and many of the skippers, present a challenge that is akin to identifying sparrows in a field of ducks and blackbirds.

Yet fall is a marvelous time to learn butterflies, as a single garden can attract a wide variety of species. That makes learning easier when one can be compared with another. And for those readers that are just starting out learning butterflies, keep in mind that a single butterfly species can vary in size by as much as forty percent, depending upon the nutrients obtained when in the caterpillar stage. The butterfly’s wing pattern is all-important. And even though a butterfly that is several days old will be faded and often worn or torn from an attack by a predator, the pattern can usually be determined.

Fall is a marvelous time of year for many reasons. The hot summer days are behind us, hurricanes are less likely, leaf color begins to change, and butterflies are galore!

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