A bit more on the Admiral Invasion

A lot of folks have been asking follow-up questions regarding the Red Admiral population boom.  Is it happening because of the mild winter or the freakishly warm weather we had in March?  Might it be a sign of global climate change? 

Red Admirals, along with a whole bunch of other butterfly species,  started showing up extremely early this year.  I had seen one by the third week of March.  That early arrival is almost certainly a result of the early warm weather.  I'm not so sure about the huge numbers being a result of the mild winter and hot spring, however.

This is an American Lady (Vanessa virginiensis).  It's a close relative of the Red Admiral- they are both in the same genus.  And like the Red Admiral, it started appearing very early.  I've been seeing them for weeks on the grounds of the Nature Museum in Chicago, where this one was photographed.  This species has not, however, undergone a population boom.  Numbers are very typical of what I have seen in in other years- just a few weeks ahead of schedule.  Whatever is happening to cause the large numbers of Red Admirals seems, at least for the moment, to be particular to that species.