This one visited today and spent a long time nectaring until a sparrow chased him off the bush!
Dark form Tiger Swallowtail. Note the visible tiger stripes and also the blue hindwing border has a dark border.
Here is a link that might be useful: Check out the photos of the dark form tiger st on this page
And the black tiger is quite a bit larger, no?
This Butterfly was huge!
Tiger Swallowtails are usually larger.
I had some huge Black Swallowtails emerge this summer. They were the size of a Tiger Swallowtail. I was awed by their size. Butterflies within the same family can be small, medium, or large. Genetics and food quality/quantity play a role in this.