This butterfly, which resembles the poisonous monarch,
ranges from central Canada through much of the United
States and into Mexico. The caterpillars feed on willows
and cottonwoods, and neither caterpillars nor adults were
thought to be distasteful to birds, although recent findings
may dispute this. Interestingly, the Batesian mimicry seen
in the adult viceroy butterfly does not extend to the caterpillars:
viceroy caterpillars are camouflaged on leaves, resembling
bird droppings, while the monarch’s distasteful
caterpillars are very conspicuous.