The Red Admiral Butterflies have been out in large flocks this spring, not only here in Tippecanoe County, Indiana but across the northeastern US and into Canada. In the fall, the Red Admiral Butterflies migrate south for their winter generation. They lay eggs and develop on plants in the South. In the Spring, their descendants begin the trek north.
Atypically large migrations have been periodically reported over the last 100 years in both North America and Europe. A mild winter throughout much of the Eastern US has been followed by flocks of Red Admirals in very large numbers. The reason for large migrations is not known, but mild winter temperatures are a suspected factor. Accurate counts of the populations are difficult, but much anecdotal information suggests that the current migration may be much larger than the large migration reported in 1990. Some observers are suggesting that this may be the largest recorded migration of Red Admirals.
Here in Indiana, the population of Red Admiral adults is noticeably smaller than it was 2 weeks ago, but a substantial, and larger than typical population remains here. To our north the warm weather in Southern Canada is leading to sightings of Red Admiral at much earlier dates than is typical.