Rare Butterfly for Connecticut (back in June)
By Patrick Comins on September 26, 2012, 3:45pm
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Rare Butterfly for Connecticut (back in June)
I'm taking a diversion from the birding weather today to talk a bit about butterflies. I received an email yesterday from Peter DeGennaro who was looking through my butterfly photos on Facebook and noticed that I had misidentified a butterfly that I had photographed back in June at the Bent of the River in Southbury. I had thought it was an orange sulphur (Colias eurytheme), a fairly common, albeit beautiful butterfly. They are generally quite skittish and I was thrilled to finally have a good photo of one, and I even caught a few blurry photos of it in flight, showing the orange upper-wings.
It turns out that I should have paid more attention to that butterfly though and that my butterfly identification skills have much room for improvement, because this was not an orange sulphur. It was a much rarer butterfly that I didn’t even consider as a possibility, a sleepy orange (Abaeis nicippe), an extremely rare vagrant from the Texas borderlands region! According to the Butterflies and Moths of North America website, their range is: “Central America north to along the United States-Mexico border; vagrant to non-mountainous parts of the eastern U. S. south of 40 latitude; rare stray to Ontario, Connecticut, South Dakota, and Colorado.” As far as I can tell, there hasn’t been a verified sighting in Connecticut since 1955!
This has been a spectacular summer for vagrant butterflies from the south. First came an invasion of giant swallwotails (Papilio cresphontes), normally a significant rare sighting in the state, but there were dozens of them seen this year.
This species normally pioneers northwards from their haunts in the southeast US. Wherever their caterpillars can make it to chrysalis stage before winter sets in makes for their new starting line the next season and when there is a harsh and early winter, they are pushed back south. Perhaps last year’s mild winter gave them a head start. With this big invasion year, the longer we make it without a widespread killing frost, the better the chances that they may start out right in Connecticut next year. Their caterpillars feed primarily on prickly ash (Zanthoxylum americanum)and hoptree (Ptelea trifoliateta) in Connecticut.
Giant swallowtails may have been the most spectacular of these southern vagrants, but other species made great northward pushes this summer as well, including long-tailed skippers (Urbanus proteus), which were reported from Stratford, Greenwich and Stamford, http://www.flmnh.ufl.edu/wildflower/Image/Butterfly/52-Longtailed-skipper.jpg . Red-banded hairstreaks (Calycopis cecrops) were also seen in greater numbers than usual and our regular southern vagrants including sachem (Atalopedes campestris) and fiery skippers ((Hylephila phyleus) were seen in abundance.
(Red-banded hairstreak)
(A sachem on ironweed)
So what is going on? A recent study from Harvard has found that southern vagrants are becoming more and more common, at least in Massachusetts. They studied 19 years of butterfly records and found that southern butterflies are being reported more often and northern butterflies less often than in the past. http://harvardforest.fas.harvard.edu/news/new-study-massachusetts-butterflies-responding-climate-change
Late September is a great time to get out and see late season butterflies, especially ahead of cold fronts when the winds are coming from the southwest, as they will be in the next couple of days http://hint.fm/wind/. Monarch are still heading south and who knows what will be heading north, and as I learned this week, sometimes it pays to look carefully! The Audubon Center at Bent of the River in Southbury is a great place to see butterflies throughout the season: http://bentoftheriver.audubon.org
The next cold front is scheduled to push through on Thursday. Thursday night should be good for migrant birds, so step outside at night and listen for birds calling as they fly overhead. Friday should be good at migrant hotspots for both raptors and songbirds.
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