Could 2012 be the Worst Year in Monarch Butterfly Migration History?

The mild winter, well-timed rains, and record wildflowers of spring 2012 resemble a lost dream as this year’s Monarch butterfly migration looks like it could be the worst in history.

Parched Goldenrod on the Llano River will serve no use to migrating Monarch butterflies except as a rest stop.

For a recap of the challenging year so far, read this post.

A visit last weekend to the Llano River reinforced the depressing outlook:   many of the usual nectar sources that fuel the migrating insects have been stopped in their blooming tracks by a lack of, or ill-timed rains and brutal heat this summer.  Declining river flow and a lower water table have contributed to the nectar shortage.

Goldenrod, usually a magnet for migrating Monarchs this time of year, stood parched along the riverbank–brown, crisp, and useless to the absent migrants, except perhaps as a rest stop.  Some stalks still remained green and those on the “Chigger Islands,” as we call them, offered only a few blooms.  Any nectar plant more than a foot from the riverbank was dead, except for Snow-on-the-Mountain.

Frostweed, a Monarch butterfly favorite, was much more scarce than last year–surprising given our better rains.   In the “historic drought” of 2011, Frostweed still thrived, but I’m guessing the timing of our rains and the Llano’s failure to recover lowered the water table so dramatically that plant roots were left dry. The 2012 Frostweed crop looks to be half or less than last year.

Some Frostweed showed its blooms on the Llano River last weekend, but not as much as we usually see in September.

Swamp Milkweed, typically a favorite host to Queens and Monarchs laying eggs along the river, showed scrawny, wilted leaves with blooms mostly spent.   We did find some eggs, though, and brought them home for fostering.

In my San Antonio butterfly garden, Monarchs are scarce.  I’ve seen only five so far and tagged ONE.  Last year at this time I had seen many and tagged two dozen by now.

A recent visit to the San Antonio River Milkweed Patch resulted in two Monarch sightings.   “We’re not seeing anything here,” said Mary Kennedy, a Monarch Larvae Monitoring Project volunteer and former science teacher, of her Fair Oaks yard just west of San Antonio.

Monarch butterflies opt for Water Hemlock when their favorite nectar sources are not available.

Dispatches from Facebook and the Monarch butterfly DPLEX list sound equally discouraging.  “I live on an acreage, and for the past 12 years, my small woods has been a roosting site,” wrote Anna Nicholas of Shell Rock, Iowa, on the DPLEX list, an email listserv that reaches hundreds of Monarch butterfly enthusiasts and scientists.

Nicholas relayed that in good years, Monarchs visited by the thousands. In bad years, only a couple hundred formed roosts. “So far… in the past week, I’ve seen three butterflies total,” she wrote.  “Throughout the summer, I seldom saw a Monarch. I never found a caterpillar on any of my milkweed. I’ve checked with friends and family members…all report the same thing. In various parts of Iowa, there simply are no Monarchs. It’s very sad.”

“Been seeing any Monarchs?” asked the Native Plant Society of Texas on Facebook recently. Answers were overwhelmingly no, and then this report from Shauna Feely of Dallas:

I have not….However, I’m in a section of Dallas county that was aerially sprayed [with insecticides] , due to West Nile virus. A definite lack of birds and bees around here….We had a very active garden, but the spraying has put a damper on things….

Aerial insecticide spraying creates an extra challenge for the migration.

And then we see isolated reports of record Monarch sightings, like this one from Pennsylvania:  “Observers at Hawk Mountain Sanctuary on the Berks-Schuylkill county line counted 2,806 monarch butterflies moving past the hawkwatch site on Monday,” reported the Pennlive website on September 11.  The tally set a one-day record at the sanctuary, Mary Linkevich, director of communications and grants, told reporter Marcus Schneck.

It’s still early in the season for the “Texas Funnel,” the strategic gateway through which all Monarch butterflies must pass en route to and from their ancestral roosts in Michoacan, Mexico.  So far, signs suggest a dismal year.  Continued rain like this weekend’s could change the forecast somewhat, perhaps coaxing late season Frostweed to push out more blooms, but nothing will resuscitate the crispy flower stalks we saw on the Llano.

Monarch Watch issued its periodic Monarch Population Status Report August 30, predicting the Monarch butterfly population this year “might be the largest since 2003– perhaps 6-7 hectares” if the weather cooperated.  Or, they speculated, we would see “another overwintering population in the 2-3 hectar range,” the worst since records have been kept.

I hope I’m wrong and am sad to say that I think it will be even worse.