Wednesday, August 12, 2015

Summer Status of Monarch Butterflies in Arizona and the Southwest

Every summer we look forward to visiting the larger monarch breeding habitats in the higher elevations of Arizona. Not only does this offer us a good opportunity for an annual habitat assessment, we can also observe when the breeding season is in progress and compare monarch adults, mating, ovaposition and larvae presence from year to year. June and July are also wonderful times to get away from the greater Phoenix area as desert temperatures soar, so we are always eager to hit the road. Here is a brief overview of some of our findings so far this year.

Queen Butterfly on Dogbane
White Mountains. In mid-June we visited Show Low and Springerville. In some years monarchs were already present in these locations, but not this year. However, both Showy Milkweed, Asclepias speciosa, and Horsetail Milkweed, Asclepias subverticillata, were up and looking healthy. We found over 20 queen butterflies, Danaus gilippus, in Springerville nectaring on Dogbane, Apocynum cannabinum, the premier nectar source for butterflies this time of year.

Pearl Crescents nectaring on A. tuberosa
Canelo. An early visit to Turkey Creek in the southeast part of the state on July 5 found the fields filled with hidden Horsetail Milkweed, A. subverticillata, but none yet in bloom. However, we found healthy Butterflyweed, A. tuberosa, packed with pearl crescent butterflies. After walking through the otherwise empty fields, we spotted one lone queen butterfly and were just about ready to leave when a spark of orange dipped in the grasses. Sure enough, there was one worn female monarch ovapositing on the A. subverticillata woven in the grasses. This is often the largest monarch breeding ground in the state, so this worn female gave us hope for a good breeding population.

Grand Canyon. July 12 found us at the Grand Canyon and we searched several common breeding areas. We only found one male monarch near the South Rim Bright Angel lodge. Still, it was early in the season and the milkweed, A. subverticillata, looked good and was in bloom. By August 3, Robb Hannawacker reported one female laying eggs and four males. A year ago during this time-frame we tagged over 30 monarchs in this same area.

Buffalo Park, Flagstaff
Flagstaff. Later in the day on July 12 we stopped by Buffalo Park in Flagstaff. There was one large male speeding through the abundant Horsetail Milkweed through the center of the park. A few days later another observer noted one monarch at the same location.

Female monarch nectaring on A. subverticillata near Show Low

White Mountains. We returned on the
weekend of July 25 to Show Low, Springerville, Eager, Rudd Creek and other White Mountain locations where the monarch population is normally firmly established by this date. In the past we noted over 20 monarchs at some locations by this time of year with several females laying eggs at each site.This year, we found only one lone monarch in Springerville and another was reported at nearby Becker Lake. The next day,  we were ready to leave the field outside of Show Low when movement in the distance caught our  eye - a worn female laying eggs - but after hours walking this normally monarch rich location, we found only this one.

Sedona & Prescott. Reports began coming in from both Sedona and Prescott the weekend of August 1, especially after a well-attended (over 100 people!) monarch presentation at Watters Garden Nursery in Prescott. Reports from Sedona (north of Prescott) began first, followed by Prescott area several days later.

Female Monarch Butterfly laying eggs on A. subverticilatta
Canelo. On August 4, three of us returned to Turkey Creek to monitor the breeding population. By now the presence of monarchs and larvae should be notable. Instead, we found only three:  one monarch was flying by the road when we first drove in, a male was on a tree branch and one female laying eggs. We did not observe any larvae, patrolling males or monarchs in quantity like previous years. Queens were notable with over 20 flying in the fields and at least five queens ovapositing. The area was very dry - the creek was dust - and only approximately 30% of the Horsetail Milkweed, A. subverticillata, was in bloom. Normally this cienaga calls for boots to slosh through the grasses. Although rains were abundant in nearby Sierra Vista and other locations, this location slipped through the monsoon's cracks. A few A. tuberosa were still in bloom and only limited A. subverticillata nectar was available in this normally rich breeding area.

Fields of verbena outside Show Low
Much can and will change over the upcoming days and weeks before the migration. Soon Horsetail Milkweed, blending well and hidden in the grasslands, will be in bloom. The rains will return and lush growth will likely follow. There are likely larvae and pupae hidden in the fields that will mature.

Each report of a monarch or immature (egg, larva or pupa) is especially important this year. Be sure to post any sightings on the Southwest Monarch Study Facebook Page or Email Southwest Monarch Study with location information and/or photos. The numbers are low, but don't panic. Remember the monarch migration will likely sweep monarchs from further north and east as well through Arizona and the Southwest. So far indicators are that many parts of the West (especially Washington) and Southwest (especially Nevada and New Mexico) are having an exceptionally good breeding season for monarchs. Our local numbers could be lower because our late Spring cool spell and freezes in the mid and higher elevations could have affected our local summer breeding population. Soon a wave of breeding monarchs will begin sweeping through the entire state about a month before the peak migration for each latitude. This will help repopulate monarchs in each region and their offspring will in time join the migration in September and October.

In case you missed it, be sure to read our paper recently published in the Journal of the Lepidopterist Society in June,"Status of Danaus plexippus in Arizona". Or you can read a condensed version, Top Ten Key Findings.

Want to tag? Tagging helps us determine monarch migration destination but also where they may spend the winter locally. Tagging also helps us learn monarch absence/presence. Email the Southwest Monarch Study for tags if you live in Arizona, New Mexico, Nevada, Utah, western Colorado or the deserts of California. Act soon - over 1,000 tags have already been distributed. The monarch migration is right around the corner!

No comments:

Post a Comment