Along the high water line on the beach at Troutburg, just west of Hamlin Beach last week, there was an amazing ribbon made up of hundreds, if not thousands, of dead and faded Monarch butterflies. A few still had the vibrant color that makes this species of butterfly so distinctive, but even those, obviously, had recently succumbed to some unknown event or condition.

So delighted are most people at the sight of these lovely butterflies, this heavy reminder of the fragility of wildlife raises questions about what might have caused so large a number of these insects to come to such an end.

We all know the oft-told tale of the impressive migrations of Monarchs. Some travel great distances to winter over in milder climates. Every autumn, Monarchs from as far north as southern Canada begin to migrate south toward Cuba and Mexico. In the famed butterfly sanctuary in the mountains near Michoacan, Mexico, millions of these intrepid butterflies congregate, filling the sky, and, reportedly, causing a ruckus with their flapping wings.

To sustain the energy for such a long journey, Monarchs stop along their journey to feed from flowers. They are under threat, too, from predators, and, in the late fall, as it turns out, the weather can be a potential killer.

According to entomologist Rob Stevenson, a former U.S. Navy Medical Corps scientist, "a prevailing wind can sometimes throw frail fliers off course and get them where they don't want to go. Also, this is the time of year insects start dying off, and a sudden drop in temperature takes its toll."

Stevenson concluded, "I suspect these migrating butterflies were just swept up and carried off course and then were killed by a sudden drop in temperature."

This could explain why so many dead butterflies were on the beach that day. Their bodies fell in to the water of Lake Ontario and were swept ashore. Nature takes its toll.

For more information ... On their Web site, www.monarchwatch.org, Monarch Watch, an educational outreach program at the University of Kansas, there is more information about a much larger but similar mass migration tragedy on southern Lake Ontario in the 1940s. They also have lots of information about Monarchs, including answers to questions like, "How do you weigh a butterfly?" The project is in its 9th year, involving students, adults and scientists in the study and conservation of Monarch butterflies.