This Week's Update Includes:

• News: On to Oklahoma!
• Slideshow: How Does a Population Grow?
• The Migration: Maps and Journal

"First adult monarch flying from plant to plant. Tried to take a picture but it's a very windy day and he was gone quickly!" Angela, Yukon, OK (April 9)

"It was the most beautiful sight I ever saw! After the reports that the population was down it was such a relief to see one." Sarah, Hattiesville, AR (April 8)

Cold Delays Development
Temperatures affect monarchs throughout their annual cycle. Gregg Lee noted this week in northern Texas:

"Cool temperatures are slowing development time, not only of milkweed but also of monarch eggs." One egg took 9 days to hatch as shown in this photo series. Chalk Mountain, Texas (April 6)

Waiting for Next Generation
It takes less than one month for monarchs to develop when temperatures are warm (80°F). However, development time is delayed when it's colder. It has been about one month since monarchs reached southern Texas. Average March temperatures were 60-70°F there, so first generation should begin to appear in Texas soon.

How Many Eggs?
Monarchs have tremendous reproductive potential. The egg chart shows how many eggs one monarch can lay. As you study the migration map, think about the eggs monarchs have laid across the landscape.

• Slideshow: How Does a Population Grow?