Monarch recovery!

One of the citizen science projects we participate in is Monarch Watch, in part by tagging Monarch butterflies on the property. Some we net as they pass through ("wild") and some we raise from caterpillars we find on the various species of milkweed we have growing on the property. The population of Monarchs in eastern North America is migratory, and spends the winter in very localized areas in Mexico -- currently covering only around 8 acres! These overwintering individuals, if they survive, move north in spring, lay eggs in the southern U.S., and the following generations continue north.

The eastern migratory population has been declining, with contributing factors including reduced availability of milkweeds (their sole host plants) due to changing agricultural practices and chemical use, and habitat loss on the wintering grounds. Population status is gauged by the area used by Monarchs each winter. In less than 20 years, well over a million Monarchs have been tagged in eastern North America. Tags are "recovered" from butterflies found dead or sighted in roost trees in Mexico. The recovery rate is fewer than 1%.

We found 2015 to be a really dismal year for Monarchs, both in terms of finding caterpillars and migrating adults. We only tagged 14 Monarchs here, half wild and half raised. Despite the odds, one of our wild Monarchs, a male we tagged on 6 September 2015, was recovered at the Monarch Biosphere Reserve in El Rosario, Mexico on 7 March 2016! This is where most of the eastern population of Monarchs winters, and is roughly 2300 miles from Ann Arbor.

A Monarch we tagged in a previous year.

Wikipedia image of roosting Monarchs covering trees on
their wintering grounds. UHT756, are you in there?