Until this fall, the 22nd of November was the latest date on which I observed butterflies. But this fall I have records from five dates in November and six dates in December, through the 20th, one day short of the solstice. On December 12th I found Colias eurytheme (alfalfa butterfly), Colias philodice (clouded sulfur), and Nathalis iole (dainty sulfur) on the wing in good numbers. On 16 December, Nathalis iole was about, basking laterally against the dark soil on a hillside. And on the 20th, Nathalis iole again, three of them. The previous record for this species was F. Martin Brown’s 3 December 1954 observation. Combined with last February’s records, we now have only about 48 days of butterfly-less weather! Here is Nathalis iole.
Colias eurytheme (alfalfa butterfly)
Colias philodice (clouded sulfur)
Autographa californica (California signature moth)
And Nathalis iole, the latest-flying butterfly on record, with a date stamp, one day before the winter solstice.