Butterfly Forecast May 15-31, 2008

The Ion Exchange Inc is very happy to recieve Harlan's permission to print his Butterfly Forecast.
Butterfly Forecast for May 15-May 31, 2008 We are starting to get into a busier and more diverse part of the butterfly season. Butterflies will be present in small numbers, and there will be more variety than we have seen so far. Among the most conspicuous are the swallowtails. The eastern tiger swallowtail, black swallowtail, and giant swallowtail are all found in central Iowa and can be seen now. Three others--the zebra, spicebush, and pipevine swallowtails--are quite rare in Iowa. Theoretically they could be present in this time period but you are unlikely to see them.
Clouded sulfurs and orange sulfurs will be the most common easily seen butterflies. Two small blue butterflies will be common as well but being small they are easily overlooked. The first is the summer azure. (Iowa apparently has both the spring and summer azure, Celastrina ladon and C.
neglecta, although they are difficult to distinguish in the field. The individuals you see during this time period are most likely to be of the summer azure.) The second is the eastern tailed-blue. Iowa has other blue butterflies but they are quite rare in most of the state. There are also some hairstreaks that can be mistaken for blues. However, 99% of all the blues you see will be either a summer azure or an eastern tailed-blue. An easy way to distinguish them in the field is that the azure will fly up into the trees when approached, and the eastern tailed-blue will fly at ground level.
Other butterflies present now include common buckeyes, painted ladies, red admirals, pearly crescents, cabbage whites, monarchs, question marks, eastern commas, bronze coppers, red spotted purples, and hackberry emperors.
If you find a good bed of flowers now is a great time to enjoy and learn about some of the skippers. We have a small patch of dame¹s rocket (unfortunately not a native plant, but it was part of a ³wildflower mix² we bought some time back). Hobomok skippers chase each other around the flowerbed. They have courtship displays that usually involve three or more individuals. It is fun to watch them chase each other and make the little jet fighter pose where one set of wings is horizontal and the other pair is at about a 45 degree angle.
Of the skippers you see in flowerbeds, hobomoks will be the most conspicuous but the slightly smaller Peck¹s skipper may also be present.
Tawney edge skippers can also be seen at this time. You may run across a small skipper butterfly that can only be described as being a brilliant black with some small white spots. You are more likely to see it mudding than nectaring, at least in my experience. That is the common sooty-wing.
There are other skippers that are dark brown or nearly black but none as completely black as this one.
Watch for the small butterflies‹they are every bit as entertaining as the large ones.

Happy butterflying.

Harlan Ratcliff

References:
Schlicht, Dennis, John C. Downey, and Jeffrey C. Nekola. 2007. The Butterflies of Iowa. The University of Iowa Press, Iowa City, IA.
Scott, James A. 1986. The Butterflies of North America. A Natural History and Field Guide. Stanford University Press, Stanford CA.
IA-BTRFLY: The Iowa Butterfly and Dragonfly list serve.
http://www.wisconsinbutterflies.org/ sightings page.
http://www.naba.org/ sightings page.
Ratcliff, Harlan: 2003-2007 Unpublished butterfly survey results.