[tlb]

As it happens, I just got back from seeing the Monarch grove in Mexico. It's an amazing sight. When the sun comes out from behind the clouds and they all warm up and take off within a couple minutes, the air is so full of them that they darken the sky. And the mountain (in Michoacan province, about 2 hours by car from Mexico City) is beautiful and the people are friendly. If you've seen the Monarch groves on the California coast, Mexico has 2 orders of magnitude more. Well worth the trip.

Our guides, showing WWF slides, told a more optimistic story about numbers. They had declined to very low levels around 2011, but have bounced back substantially. They said the small decline in the last 2 years might be normal variation due to weather. The graphs showed random variation in population by a factor of 2 from year-to-year going back to the 1970s, so it's probably hard to conclude anything from a single year's count.

Still, if you live along the migration corridor, please plant milkweed and don't use glyphosate weed killer.

[KMag]

Note that there are multiple species of milkweed. If you find milkweed unappealing, look into other species. In the late 1980s/early 1990s, I found a couple of monarch pupae on some plants in the wetlands in my back yard. The plant stems were more stiff and the leaves less velvety than the milkweed I was familiar with in the local park.

I asked our local nature center if Monarchs only eat milkweed, why they would pupate on this plant. They identified the plant as https://en.wikipedia.org/wiki/Asclepias_incarnata , a variety of milkweed.

[deadmetheny]

A retaining wall in my backyard has a growth of Cynanchum laeve (honeyvine milkweed) and English ivy - it looks rather nice, and every year I find a handful of monarch caterpillars happily munching away at the leaves. While the vines can spread and be very invasive if not controlled, they co-mingle with ivy very well. I greatly appreciate them being part of my garden.