Here are some reasons scientists have had a hard time studying monarch roosts during fall migration:

• It's hard to find a roost!
• Roosting monarchs are quiet. People can't hear them.
• Roosting butterflies are hard to see. They are well camouflaged. They look like leaves and are often high up in the trees.
• It's dark most of the time a roost is present. The monarchs arrive at sunset and may leave early in the morning.
• Roosts form in unpredictable places; they can't always be found in the same place every year.
• Roosts don't stay in a place for long.
• The area monarchs migrate across is large.
• The fall migration season is short, and happens only once a year.
• Scientists have busy lives. They might not have time to travel during fall migration season.

It's hard to study something if you don't know when or where to find it! This is why observations made by citizen scientists can be so important. They can contribute observations that are difficult or impossible for a scientist to make.

Image: Pat Swerkstrom