What a wonderful sight. Here in the UK, the extremely wet summer this past year meant that we saw very few butterflies; our buddleia in the garden usually plays host to a number of species. Never seen anything like that swarm in your photos though. Thanks for sharing.
D4, D800, D600
It ain't so much the things we don't know that get us in trouble. It's the things we know that just ain't so.
Why is this thus? What is the reason of this thusness?
I live in Oklahoma, and last year was poor for butterflies. We are in a 3 year drought, and I believe the few hummingbirds and butterflies are related to a decrease in wildflowers. Texas, Kansas for sure is in drought, who knows where else in the states but I do know the corn belt up north was hit hard, too.
Maybe that's why Alberta got more than your usual number. Slim pickings here, so they just kept moving north!