Late-season cold and accompanying north winds appear to be holding the monarchs back. However, the wind will shift to a southerly flow by Thursday, May 19th and is predicted to blow for most of the week ahead. Watch for northbound butterflies to ride the tailwinds into the summer breeding grounds. Flying conditions will be perfect.

With monarch numbers low, few sightings were reported during the past week. The migration map shows scattered sightings in the north, including surprise first sightings from Canada.

Compare Years
The timing of arrival in the northern breeding grounds is important and it can vary from year to year, as the migration maps show. Arrival time is one factor that influences the size of future generations according to Dr. Chip Taylor. He thinks the ideal window is the 10-day period from May 11 - 20. Let's see what happens in the week ahead!

Watch Out for Look-Alikes
Thousands of observers track the monarch's migration every spring. These people expand the eyes and ears of scientists, but proper identification is critical. Look carefully for the monarch's tell-tale field marks — and try to snap a picture. We review all sightings reported to the migration map and will contact you if we need more information for verification.

Post-Storm Logging
More bad news from Mexico. Large-scale salvage logging is being conducted in the aftermath of the March 2016 storm that struck the monarch overwintering colonies, further degrading the forest's protective canopy, say experts. We will continue to follow this news and look for ways people can express their concern.