The Monarch Conundrum

In the Big City there has been the annual staging of the monarch butterfly migration.  The butterflies are on the move for parts south. It is pretty cool and since the city apartment Jill and I keep is immediately adjacent to a roost site a couple of times a year we get to observe the migration action up-close and personal.  If you haven't witnessed it before - it is quite cool. 

There is a very active monarch restoration network working hard in an urban environment to restore habitat and support the migration.  Photos, video and more information about the Friends of the Monarch Trail here. 

Anyone reading this blog also knows that, Jill and I maintain a reasonably large pollinator habitat here at The Platz.  It has been a terrific year for butterflies of all types including the monarchs.  Yet to my eyes there hasn’t been much sign of departures on a migration.   As a matter of fact the comings and goings of the monarch butterflies seemed pretty normal with numbers what we have become accustomed-to over the past few months. 

click on images for a closer look

 

The photos in this post were taken last Sunday and Monday and include at least three stages of monarch development.   

Since none of these insects seemed to be in a rush to beat it out of Dodge I was puzzled by this conundrum.  Was it a consequence of northern latitude? A milder clime on the peninsula?  What gives?  

Talking to some of the people in the Big City I was lead to believe that the monarchs were on their city roosts, departing for parts south and there wasn’t an explanation for anything I observed at latitude halfway between the equator and the pole. 

Pre-emergent - you can see the butterfly within
 
Thursday morning I was chatting with a guy setting-up a tripod and camera to photograph the city monarchs and he didn’t believe a word I was sharing with him.  All the monarchs were in Wauwatosa – wasn’t it obvious to me?  As far as he was concerned I might as well have lived at the North Pole.  I was either nuts or making stuff-up.   

Rescued from the composter and it pupated before my very eyes

 

So were the monarchs observed here on the peninsula too late to the migration dance? What was the backstory?   Curious, I fired-off an email on the subject to the Department of Etymology at UW Madison.  I received a reply yesterday afternoon and learned that the migration is both complicated and nowhere near over.   From the experts was this: 

Hi Tom,    

Thanks for your inquiry about monarch life history. This is a complicated time to sort out generations, life stages, and behaviors because so many things are overlapping. Monarchs that emerge as adults after about the third week in August will migrate, and not reproduce.

However, there are still reproductive monarchs around that emerged earlier, some from the local area and some from farther north. My guess is that you're seeing the immature stages (eggs, larvae and pupae) that are the offspring of the last reproductive monarchs of the season, and that the adults in your garden are a combination of migrants and these late reproducers.   

This weird overlap goes on for about a month; you should stop seeing the immature monarchs in a week or so, but will keep seeing migrants for a month or so (especially since it sounds like you have great habitat for them).  Thanks for all that you're doing to support monarchs and the other species that use their habitat. 

Just emerged and drying-out

 

So, there you have it.  There is overlap and it is complicated.  Raising a toast to science and a few more weeks of monarchs to be enjoyed...