Cloud Effect
Basking butterflies explode into the air when a cloud obscures the sun. Dr. Tom Emmell witnessed the cloud effect:

"The monarchs would come out of the trees each time that cumulus clouds covered the sun. They reached almost unbelievably dense numbers, flying out over the llanos. The trees were nearly emptied at such times. Literally every cubic foot of air held at least one monarch." El Rosario Sanctuary, Feb. 21, 2015

Lipids Are Low
The monarchs' energy reserves should be about 70% depleted by now, as the lipid graph shows. The typical monarch may have only 60 mg of the 140 mg it had when it arrived in November.

Great ready! Plant nectar-rich flowers. Hungry monarch butterflies will soon be heading your way.