Monarch population size over winter 2016-2017 announced!

The estimates of the monarch butterfly overwintering population were announced Thursday February 9th by WWF Mexico.  The butterflies are so dense at their dozen or so mountain-top clustering sites that overwintering butterflies cannot be counted.  Instead, the area of forest that is densely coated with butterflies (at about 5,000 butterflies per square meter looking up into the canopy) is estimated… Read more

Where do monarch butterflies come from?

The plight of monarch butterflies is often in the news and many scientists around the world are working hard to understand their annual migratory cycle.  How do the monarchs produced during summer in the northern reaches of America contribute to the overwintering population in Mexico?  The origins of monarch butterflies that make it to Mexico has been hotly debated and… Read more

Monarch book!

My new book, Monarchs and Milkweed, a highly illustrated popular science book will be available in late March from Princeton University Press.   Here is what Carl Safina, author of Beyond Words: What Animals Think and Feel, says: It’s impossible to imagine the world without monarch butterflies. But they face mounting challenges. This clear, fact-packed book looks at this astonishing and… Read more