Thursday, October 17, 2013

Butterflies, Herbs and Wildflowers - 'Tis the Season

Sweetbush, Bebbia juncea
Fall is the season for planting in the desert. Warm soils encourage roots to develop before the cold of winter settles in stalling growth. University of Arizona Extension studies have shown Fall planting helps new seedlings handle our hot summers as well with a solid understory foundation more readily adapting to our limited water. Several milkweeds (Desert Milkweed (Asclepias subulata), Arizona Milkweed (Asclepias angustifolia) and Pineleaf Milkweed (Asclepias linaria) are featured at many seasonal plant sales as are rich nectar sources like Desert Ageratum (Ageratum corymbosum), Sweetbush (Bebbia juncea) or Lantana (Lantana camara). But don't forget herbs and wildflowers that attract our earliest butterflies during the cooler season as well.

Fernleaf Lavender
Every winter a few monarchs spend the winter in the greater Phoenix and Yuma areas. These are likely monarchs that eclosed late in the season. Some may be breeding monarchs but many are in reproductive diapause and will delay mating until spring. Whether breeding or not, monarchs will need strong nectar to help sustain them during the cooler months.Winter blooming Fernleaf lavender is a monarch favorite. Calendulas are as well, so keep a few around in pots for monarchs that survive our light freezes in the area.

Wildflowers are easy to grow and many reseed for future seasons. Premier planting time in the lower deserts is from October through the end of November. Simply sprinkle seeds thinly and rake in. You can spread seeds over granite or soil. Small seeds may be easier to distribute mixed with sand. You can let nature take its course with our winter rains, or you can help secure a spring floral display by watering lightly until new growth is up. Only an occasional drink of water is needed if our rains are late.  On warm winter days you may spot a few local butterflies visiting your patch before anything else is in bloom, a regal thank you for your effort.

Bakers Nursery in Phoenix has large vats of wildflower seeds you can purchase by the ounce that grow well in our Sonoran Desert. The Desert Botanical Garden Desert Botanical Garden Wildflower Sources is a handy resource to order seeds in time for planting as well. So think wildlife with wildflowers this winter and keep your eye out for out of season visitors to your yard.

Friday, October 11, 2013

Untangling a Long Distance Monarch Flight

I heard the news first yesterday morning. A monarch wearing a Southwest Monarch Study tag was sighted near Morro Bay, California. Later I discovered that a monarch wearing AD 947 was tagged by Joe Billings on September 15 in Hereford, Arizona. It was spotted in Cayucos, California on October 9 by Paul Cherubini, a flight of approximately 675 miles.

We don't know the flight path, only the two observation points. Typically monarchs on their Fall migration will fly South or Southwest from the Eastern United States. Much is still unknown in the West although some tests were observed with farmed monarchs (captive monarch butterflies bred for sale) that were moved around the Western states and released. However, there were not any controls with wild monarchs nor records of wind direction and weather conditions at the time.

From earlier studies about migrating monarchs we do know that they are very susceptible to winds. Dr. Chip Taylor of Monarch Watch observed, "Our tagging records are full of monarchs that have been pushed off course - one by as much as 800 miles. Remember the posting (D-plex) recently on monarchs from the Dakotas, MN, IA with many pushed to the SE?" Furthermore, studies have also documented that monarchs are resilient and can reorient their flight pattern within a week after they are displaced.

Purple arrow indicates wind direction
While most of the recoveries and sightings from tagging monarchs in Arizona during the Fall migration have been in Mexico, a few were seen in California. Monarch scientists have urged us to check weather patterns and winds in the days shortly after tagging to see if they can reveal a clue. So yesterday that is what I did. You can see from this map that in the first days after this monarch was tagged, winds blew at a good clip from the Southeast to the Northwest facilitating movement in that direction. Monarchs also use thermals to gain altitude to fly and with the warmth of nearby mountains basking in the sun, rising air could have easily facilitated vertical movement that could have made a flying monarch more vulnerable to wind gusts. The National Weather Service also reported a storm in the area that day with winds blowing towards the Northwest. Dr. David James, Associate Professor of Entomology at Washington State University, noted, "Yes wind makes a lot of sense. Once individuals get to a certain point towards the coast, its likely other factors take over, ensuring their final destination is the coast."

The truth of the matter is we just don't know. We do know that this year the seasonal monsoon wind pattern was more entrenched than earlier years until late September. We can't say for certain that the winds blew this monarch to California, but we also can't say given the winds that week, that they didn't.

Wednesday, October 9, 2013

Grand Canyon Monarch Butterfly Population

Monarch nectaring on sunflowers at the Grand Canyon
Our favorite vacation destination is the ever changing Grand Canyon National Park in northern Arizona. While the etching of this great geological wonder is slow, for over thirty years our family has uncovered new discoveries each time we visit about it's many natural splendors.  When we were young, we hiked the trails absorbing the ages of time around us. Once, to make our travels light, we rode the mules. We learned quickly that for us hiking was much easier. We’ve rafted the mighty Colorado River several times between the steep Canyon walls and over treacherous rapids. We have fallen asleep to the roar of monsoon storms pummeling the deep gorges with thunder echoing and rebounding off the walls. More recently we enjoyed a cabin on the South Rim savoring the Canyon’s many moods – and watching monarch butterflies shoot up out of the Canyon each afternoon like bullets from the river far below.

Monarch nectaring on New Mexico Vervain
The number of monarch butterflies we see at the Canyon fluctuates. Last year they were abundant, the most we’ve ever seen. This summer the monarch population was more typical, but still exciting to watch. Like earlier visits we witnessed egg-laying and larvae, pristine and shredded winged monarchs, and enjoyed watching adults nectaring. But monarchs often reveal new survival strategies when the circumstance is right and it’s fun to look for them. This year we found monarchs nectaring on New Mexico Vervain, Verbena macdougalii, in damp meadows. Of course they still favored Horsetail Milkweed, Aslcepias subverticillata, Rabbitbrush, Chrysothamnus spp., and Sunflowers, Helianthus spp., as well.

Monarch nectaring on Rabbitbrush
The Grand Canyon is home to three varieties of Rabbitbrush and each has its own bloom period. As one is senescing, another is just coming into flower. As a result it is a major and continuous late summer and Fall nectar source. Monarchs chase the rabbitbrush bloom around the Canyon then stay in nearby trees for shelter, a perfect bed and breakfast.  We found monarchs roosting in pine and junipers alike, usually on the South and Southeast portions of trees. You could often find them shortly after sunrise sunning with open wings to warm before dipping down to feed.

Monarch on Horsetail Milkweed, Asclepias subverticillata
Like previous years, monarch numbers were densest at the edge of the canyon closest to the Bright Angel Cabins. We stood by the rim on warm afternoons and watched monarchs fly up out of the canyon, then appear to hover a moment, and gracefully glide over treetops to nearby milkweed and nectar just to the South. From sightings along the South Bright Angel Trail it appears they follow the creek and nectar up through Indian Gardens then follow the canon gorge up.

Joe, an Interpretive Ranger at the Grand Canyon
But there was something very different about the Grand Canyon this year - the National Park Service employees chasing monarchs. Joe joined us tagging last year and was the first to create a Ranger monarch logging system for our data to record sightings by the public. There is something very special about spotting a ranger with a net on his back riding around the Canyon looking for monarchs!

Marna, Grand Canyon Park Guide
Marna, a Park Guide for the National Park Service, was inspired by her encounter of monarchs last year to create this beautiful detailed monarch painting that hangs above her desk.

Monarch larva
This year we were invited by the National Park Service to share monarch presentations at the Grand Canyon school for the K, 6, 7, 8 and 10th grade classes. Afterwards, each grade walked around the school grounds to identify monarch host and nectar plants. The sixth grade class was the first to find a monarch larva on Horsetail Milkweed, Asclepias subverticillata! Classes decided on seeds to collect and grow in their greenhouse this winter. We'll return next Spring to help with their Earth Day butterfly garden installation for their phenology project. 

In the evening we shared a public presentation on Monarch Butterflies at the Grand Canyon at the Shrine of the Ages. We were excited by the international interest in the monarch migration phenomena. For us it was a wonderful experience to be able to share new understanding about the monarch butterfly migration through Arizona at a place that has touched the heart of our family so deeply for a lifetime.