Saturday, May 31, 2014

Spring Monarchs in the Desert

She flew in while we were working in the yard. We paused a moment and watched, frozen in place so we wouldn’t frighten her away. It was  April 8, and we were delighted to see a female monarch stop by to visit. She flew from milkweed to milkweed feeding deeply from their flowers then rested a bit. Then she began exploring the yard and we stepped back to enjoy her Aslcepias survey.

Pineleaf Milkweed, Asclepias linaria
Pineleaf Milkweed, Asclepias linaria, captivated her interest first as she eagerly examined each branch, finally selecting one for her first egg. We were amused by her choice of the Pineleaf - usually it is not a monarch favorite. Her milkweed dance continued and after laying several eggs she rested a moment nearby.

She fluttered over to Desert Milkweed, Asclepias subulata, and Arizona Milkweed, Asclepias angustifolia, patiently exploring each branch and selecting flower after flower then leaf after leaf, to lay her day’s bounty of eggs. Finally she discovered the Tropical Milkweed, Asclepias curassavica, now in the early afternoon shade. She left over 30 eggs that day and we marveled at our good fortune to be outside at just the right time and place to watch her story unfold.
Arizona Milkweed, Asclepias angustifolia
Desert or Rush Milkweed, Asclepias subulata
Tropical Milkweed, Asclepias curassavica

In time there was a traffic jam on A. angustifolia
She wasn’t done. She was back the next morning – and every day afterwards for the next three weeks. In the Spring, female monarchs are not common in Arizona. We don’t know quite why this is the case. Intense, blustery Westerly winds are a hallmark of Spring in the state. Perhaps monarchs flying up from Mexico are unable to fight their forceful throws, yet one would think this would aid migrators from California. But every year a few monarchs do appear and we were lucky to see one. Usually when a female monarch arrives she will lay her eggs, rest for the night and then continue on her migration the next morning or stay an extra day at most. So to have her live out her natural life here in our yard was quite unusual.

It was a delight to see her each day visiting different corners of the milkweed patch in our yard. It was stressful as well when she discovered the young milkweed we had for a weekend sale and promptly decided the fresh new seedlings were perfect for her eggs. Luckily we were able to move most of the eggs and small larvae that we missed at first to hardier plants. All in all over 70 monarchs eclosed in our yard over the past ten days and over 60 small larvae were distributed to my “caterpillar exchange” friends and schools. Who says there are no monarchs in the desert?

Oh, the story didn’t end with this one female monarch. While most freshly eclosed monarchs stayed a day to nectar-up and then left on their migration north, a few stayed. Those that stayed mated. There are signs of new larvae on the milkweed that recently just leafed out after the earlier larvae defoliation. I asked Dr. Chip Taylor of Monarch Watch why eight monarchs were staying in our yard during a time they are hard-wired to migrate. After hearing about our above normal temperatures he said,“It's too hot to migrate. Most of the movement takes place when temps are 65-85F. Optimal temps for migration are in the mid 70s.” 

So, we’ll enjoy our monarchs while we have them. They've adapted well to our 100 degree plus high temperatures by flying and feeding early at 6 a.m., resting in nearby trees and bushes in the heat of the day and then flying again in the late afternoon until sunset.  The continued high temperatures in the coming week will likely halt this unusual late spring activity in the desert. But, still after recent highs of 107 degrees, monarch larvae continue flourishing in my backyard (see photo below). Truly this is a monarch Spring to remember!

Backyard - 5/30/14:  Three monarch larvae on A. angustifolia


  1. I love this! It gives me hope for my small urban way station here in Phoenix. Keep up the good work. the milkweed I bought from you is growing well.

    1. That's all I have, Heather! Just a small yard in the city. For monarchs and all wildlife really it is all about density. Butterflies throng to large pockets of nectar and their host plants. Here in the harshest part of the desert they need trees and large bushes for shade and cooling as well as a water source. It can be as simple as an extra drip line. Can't wait to hear about your garden as it matures! Remember, the Fall is our premier butterfly season, so you'll be ready.