A second impressive ‘wave’ of butterfly migration has been taking place the last few days. More Red Admirals have been joined by some other migratory butterflies: Painted Lady (saw one in the schoolyard yesterday), American Lady, Common Buckeye, Question Mark, Mourning Cloak, Cloudless Sulphur, Gray Hairstreak, Variegated Fritillary, Little Yellow, American Snout, Dainty Sulphur, etc. The list is a long one. The occasional Monarch has already been recorded as well!
Some species of butterflies overwinter as adults or chrysalids and, not surprisingly, these are active now too. Cabbage Whites have been out since March but there are Meadow Fritillaries, Grey and Green Commas, Peck’s Skippers, Spring Azures, Spicebush Swallowtails and more!
Migrants will often touch down first at Point Pelee and many of the early reports are from there or near there. In fact, one butterfly watcher has recorded over 19 species from there already! See Ontario Butterflies if you want to read more.
People are asking ‘Why do there seem to be so many butterflies this year?’ Partly, the answer may be that conditions in the overwintering grounds were ideal for survival of these species. It also has to do with the winds and mild weather. In March and early April, the wind in southern Ontario was mostly from the north, when we got a southern blast of wind in mid-April, the butterflies were able to ‘ride’ it here. It has happened again.
A second question on people’s mind, is will they survive a drop in temperature and/or rainstorms? While there will be some butterfly mortality associated with violent thunderstorms, butterflies know to seek shelter and do so. As for the temperature, a really cold snap (such as -10oC) would really put a dent in the population but cool temperatures (even hovering around 0oC) won’t kill them all. They do find warm sheltered spots to wait out the bad weather.
If you are interested and confident of your identifications, you should check out ebutterfly, a website developed by Maxime Larrivée and colleagues at the University of Ottawa, for tracking butterfly sightings in Canada.
For more information about butterfly migrations in Ontario, see Antonia’s previous blog about the Red Admiral Migration “Monday’s Massive Migration“.