It was an unusual sight Tuesday in Riverside Park. A group of University at Buffalo students armed with white, mesh butterfly nets fanned out over the Olmsted park in the northwest corner of Buffalo in search of common milkweed.

The unadorned, bushlike plant with the oblong leaves might be considered an unattractive nuisance in most gardens.

However, it is the primary source of sustenance for the monarch butterfly. It was purposely planted in various spots in the park by the Olmsted Parks Conservancy to attract the butterfly.

That makes Riverside Park an ideal place for capturing and tagging the colorfully winged critters before they continue their migration south, said Dr. Nicholas Henshue, a professor in the Department of Environment and Sustainability at UB.