Monarch butterflies are a tropical species and cannot survive extreme freezing temperatures. Most migrate in the Fall to Mexico or the coast of California to weather the winter. A few monarchs do not make it to these well-known overwintering sites. Small numbers scatter along the Southern United States Gulf coast and a few areas here in Arizona. Their habitat is not ideal. Monarchs at the Desert Botanical Garden and Tempe Marsh perished in the freeze of early January. When a hard freeze warning appeared in the Phoenix area forecast last week, many of us were concerned. Once again the monarchs surprised us. Despite low temperatures in the upper 20's at Rio Salado, some of the monarchs survived. After highs only in the 40's last week, Saturday was the first day warm enough to see any butterfly activity. But the skies were hazy and temperatures only in the low 60's. There was only one butterfly out anywhere - a male monarch.
Rio Salado 2-6-11
Sunday was warmer and more butterflies appeared. Two male monarchs joined several West Coast Ladies and American Snouts on stands of Seep willow that survived the freeze. Some of the outer flowers were affected, but most blooms were fresh and robust. The Sweetbush, Bebbia juncea, was stunted by the extreme cold just a short distance away. The thick tree density and winding creeks provided a protective canopy during the night's plunging temperatures.
Rio Salado 2-7-11
On Tuesday I visited Rio Salado again and witnessed two blue-tagged monarchs mating as I walked in. I followed them on their love-flight to a nearby tree and with photos and binoculars tried to read their tag numbers. It took some juggling of photos to identify them with the sun glaring off of the glossy surface of the tags. But we were able to see 576M, a male tagged on 12/28/10, and 577M, a female tagged on 1/9/11. Both 576M and 577M have been spotted several times since they were tagged in the habitat area. Monarchs usually begin mating right around Valentine's Day, February 14th. Up to now we have not seen any monarch mating activity, although the queen butterflies were mating the past month.
Rio Salado 2-8-11
I talked to Rio Salado management who joined me to see this exciting event. There are 19 milkweed plants, Asclepias subulata, at the habitat. Most were showing the beginning of tender new growth shoots where female monarchs like to lay their eggs. We decided to add seven more host plants quickly. That evening I called Laura Miller and she joined me to plant three more Desert Milkweed, Asclepias subulata, and also three Pine-leaf Milkweed, Aslcepias linaria. When we arrived 576M and 577M were near each other at the same location. While we were digging holes for the new milkweed we saw them flutter away in the warming sun eventually nectaring again on the stands of Seep Willow nearby.
It is important to protect the monarch butterflies, larvae and pupae at Rio Salado Habitat Restoration Area and a permit is now required to monitor the area. A group of volunteers who regularly care for the overwintering area are continuing to work with Rangers and Staff to closely watch the site and keep the public from harming the monarchs, their caterpillars or chrysalids in any way. Want to help? Participate in the Pennies for the Planet campaign. Rio Salado is a recipient of funds for monarch habitat restoration including adding more milkweed, signage and educational programs.
Gail is the Monarch Watch Conservation Specialist for Arizona, the Coordinator of the SW Monarch Study and serves on the Board of Directors of the Monarch Butterfly Fund. She is also a trainer for the Monarch Larva Monitoring Project and participates in Monarch Health. A life-long gardener, Gail completed the Master Gardener Training in 1996 and the Desert Garden Mastership Program in 2011. She is also a volunteer for AZ State Parks, Rainlog, COCORAH, a storm spotter for the National Weather Service in Phoenix and a member of CAzBA (Central Arizona Butterfly Association). Her husband, Bob, joins in the fun and enjoys photographing wings and things in the field.