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The Poweshiek Skipper Project | |
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Lake Hawthorne ©Rayford
Ratcliff
Introduction Information about the butterfly
O.
poweshiek, Legacy butterfly Legacy
of Chief Poweshiek
H.W. Parker's writings Von Blixum's Heroic Experiment
Iowa's
biological diversity
The Poweshiek Skipper Project Goals
of the project
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Butterfly Forecast for Central Iowa March, 2010 We have had four days now where temperatures reached above freezing. A few more weeks like this and some of those six-foot piles of snow will almost be gone. I saw a forecast from the National Oceanic and Atmospheric Administration (NOAA) dated October of 2009 that predicted the winter of 2009-2010 to average about 40% warmer than a typical year, due to the effects of an El Nino. Fortunately for the highly educated and trained scientists who created the report no one signed it. (The report may still be found here). So it is with a little reluctance that I put a forecast out there for butterflies.
It has been a hard winter on warm-blooded mammals like ourselves, but I suspect that it has not been so hard on the cold-blooded butterflies (and their caterpillar, pupae, and egg stages) that spend the winter in Iowa. There was an early deep snow cover, and while temperatures have been pretty cold there have not been a lot of freeze-thaw cycles that bring the insects out of dormancy early. In fact, I think we will see pretty large populations of the group of insects that spends winter as adults and will be the first we see. Those include the mourning cloak, Nymphalis antiopa, eastern comma, Polygonia comma, question mark, P. interrogationis, Milbert's tortoiseshell, Aglais milberti. These butterflies are very possible for March. I think the photo above is a question mark, but it is almost intermediate between that and the eastern comma. Butterflies that over winter in the earlier stages will show up in pretty good numbers in April. There are a number of butterflies, including the monarch, which spend the winter in the areas to the south of us where it never (almost) gets cold and it never (almost) snows. Those butterflies do not tolerate cold well. This year has been exceptionally cold in those areas--it has snowed as far south as Mexico this winter. I would expect unusually low numbers of these butterflies in the summer of 2010. They include the monarch, Danaus plexippus, painted lady, Vanessa cardui, American lady, V. virginiensis, red admiral, V. atalanta, buckeye, Junonia coenia, and little yellow, Eurema lisa. But then forecasters have been wrong before. Let me know if you see any butterflies within the next few weeks. 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. www.wisconsinbutterflies.org sightings page. www.NABA.org sightings page. Ratcliff, Harlan: 2003-2008 Unpublished butterfly survey results. |
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When
we first start to see butterflies is pretty dependant on the
weather. With colder than normal temperatures and a longer than
normal period with snow on the ground, it might be expected that the
butterflies will be later than normal. I suspect that will be
true. I don't really think we will see butterflies here in Iowa
until the last half of the month of March, and they might not even appear
until early April. If I had to put money on it, I would guess the
last week of March, but of course that depends heavily upon the
weather.