Friday, January 31, 2014

The Plummeting Monarch Butterfly Population

The news is grim. The monarch butterfly population overwintering in Mexico plunged to a new low this winter. The signs were there earlier. Cooler than normal temperatures during the Spring migration delayed monarch movement into the northern part of the United States and Canada as well as slowing the growth of immatures for the next generation. The Fall migration was late mainly due to the late maturation of the migrating generation. Fortunately the weather along the migration route was warmer than usual across the board, helping monarchs reach Mexico to some degree. An early freeze could have been even worse.

Monarch Butterfly Fund -
How late? Monarchs usually begin to arrive in Mexico during the annual celebration of the Days of the Dead, Día de Muertos, on November 1 and 2. Fluttering orange wings of monarchs dancing through the skies, traditionally believed by local people to bring the return of the souls of deceased children and loved ones, were silent. Empty. No monarchs graced the skies to the lament of those holding this annual tradition dear.

Once the monarchs finally did arrive in Mexico the weather near the overwintering sites was inhospitable to further movement, cool and sometimes rainy, making it difficult for the monarchs to fly their final miles into the oyamel forest. But they did arrive in early December, nearly a month late.

When the monarchs first arrive in the oyamel forests they usually are dispersed through an area. As the temperatures get colder, they compact in clusters in the trees. Measurements of the monarch population are recorded frequently. For comparison, the count of the monarch population at the end of December, the time of the coldest temperatures and when the monarch clusters are the most compact, are used for comparison each year and are reflected in the graph above.

So the real question is, now what? We're grieving. Some are panicking and rushing into desperate plans that may not really benefit the monarchs in the long run. Take a few moments to think through what we all can reasonably do. In a conversation with Monarch Watch Conservation Specialists recently, Dr. Chip Taylor pointed out this sobering thought. "Yes, the numbers are low but they have surely been lower in the past. No one remembers the dirty thirtys - 8 years of drought and high temperatures. Based on how monarchs respond to high temps and drought in recent years it is likely that monarch numbers were lower in the late thirtys than they are now. The difference between then and now is habitat. There was more habitat then. The habitat loses now are extraordinary - over 24 million acres plowed under since 2008 and about a million lost each year due to development." You can read more important details about habitat loss in this recent Monarch Watch Blog .

Dr. Karen Oberhauser, Director of Monarch Larva Monitoring Project (MLMP), shared this sobering call to action when the population numbers were announced:"Four concrete things that people can do include:
  1. Plant locally sourced, native milkweed and nectar sources wherever possible
  2. Educate others and advocate for monarch conservation.  People can register their monarch habitats as monarch Waystations and add them to other success stories on the Monarch Joint Venture website.  They can talk to friends and neighbors about monarchs, ask local or county land managers to avoid mowing milkweed when monarch eggs and caterpillars might be present, and advocate to limit insecticide spraying at the local, state or national level
  3. Get involved in a monarch citizen science program and contribute data that will help us manage monarchs more effectively
  4. Donate money to organizations that support monarch, pollinator, and land conservation. 
Conservation  biology is essentially a science of hope, and the number of organizations and passionate individuals involved in monarch conservation across North America gives us reason for hope.  Given the conservation challenges facing monarchs and the clear evidence that their populations are declining, it is vitally important that we mobilize as many people as possible, and that our efforts are carefully planned to maximize their impacts.  For many people, monarchs represent a connection to nature that began in childhood, and our actions will allow generations to come to make this same connection." You can read more of Dr. Oberhauser's press release here.

 In response to the record low monarch population in Mexico and the increasing loss of monarch habitats in Arizona, the Southwest Monarch Study has partnered with Borderland Restoration Nursery to offer organic, pesticide-free milkweed for your gardens and nature centers. This Spring beginning in March we will have Desert Milkweed (A. subulata) and Arizona Milkweed (A. angustifolia) for the lower desert region. By May, for the higher elevations, we will have Showy Milkweed (A. speciosa), Butterflyweed (A. tuberosa), Antelope Horns Milkweed (A.asperula), Broadleaf Milkweed (A.latifolia), and for areas without horses/cattle we will also have a limited amount of Horsetail Milkweed (A.subverticillata). Your seeds are growing now. For more information as plants are available, please follow the Southwest Monarch Study Facebook page,

Milkweed seedlings at Borderlands Restoration Nursery

Sunday, January 26, 2014

Monarch Butterflies at Buckskin State Park

Tagged monarch spotted in Lake Havasu 2-17-13

We spent last weekend at Buckskin State Park in Parker, AZ, along the Colorado River. When we last visited in November we were lucky to find migrating monarch butterflies. With our unusually warm winter this year we wondered if any monarchs would still be around. Just a year ago Keith Graves tagged a monarch in November at Rotary Park in Lake Havasu and on February 17th a local resident, Karen, found the tagged monarch. Naturally we were curious to see if we could spot any overwintering monarchs around this year.

Male monarc nectaring on Lantana
It didn’t take long. We arrived after 4 p.m. and Bob took a quick walk to stretch his legs before setting up camp. When he returned he was holding a monarch! Turns out a few monarchs were nectaring on a nearby lantana. We have a permit to tag monarchs at the Arizona State Parks so we were delighted to find one so easily. While tagging is usually done in the Fall to track the monarch migration, it can also help us learn if a monarch stays in an area. Every year the Southwest Monarch Study saves tags dedicated for winter tagging to help increase our understanding of monarch behavior.

Monarch in Willow Acacia, Acacia salicina
We were looking forward to learning how many monarchs were in the area on Saturday. The night temps were on the chilly side in the low 40’s. Nearby mountains shelter the rising sun, so it wasn’t until late morning before temperatures warmed and monarchs slowly began to appear. Like last November, they still favored the Willow Acacia trees, Acacia salicina, as night roosts and many trees still had limited blooms for nectar, an ideal “bed and breakfast.” 

Male monarch on Ficus, Microcarpa retusa
We also spotted monarchs in nearby Ficus, Microcarpa retusa, as well. All in all there were approximately 25 monarchs in the area. This time we only saw two Painted Ladies and didn’t see any Queen butterflies. Monarchs ruled. Daytime temperatures were in the low to mid 70’s, perfect for butterfly activity. 

Campers Vera Walters and Cathie Hartin help tag a monarch
A few monarchs were hungrily feeding at large lantana bushes that were no longer in their prime, but still suitable nectar on Saturday afternoon. I just netted one monarch to tag, when Vera Walters and Cathie Hartin walked over to help. They both visited the overwintering monarchs in Mexico a few years ago and were surprised and excited to see monarchs at Buckskin State Park. 

Bill Williams River Natural Wildlife Area
Bob and I also drove up to Bill Williams River Natural Wildlife Area. The ranger on duty mentioned that the area was extremely dry with the deep drought, but even so we were surprised at how desolate the riverbed was on our hike. Most of the trees had died back and there were only limited pockets of green foliage of Seep Willow, Baccharis salicifolia without any blooms. We didn’t see any butterflies of any kind.

Sweet Bush, Bebbia juncea
We continued to Lake Havasu to check Rotary Park and other riparian areas around town. Nothing was in bloom but we did see one monarch flying north along Highway 95. There was abundant Sweet Bush, Bebbia juncea, all along the road that surprisingly had pockets of good blooms, but no butterflies of any kind. 

Monarch well camouflaged in the dead leaves
From our quick trip up the Colorado, the monarchs were following the nectar – and this year the nectar was at Buckskin State Park to the delight of everyone from around the United States and Canada camping.

Monday, January 6, 2014

All in the Family – Queens in the Winter Desert

Monarch butterflies, Danaus plexippus, and their larvae are not the only members of the Danaus family  in desert milkweed gardens this winter. Yesterday I decided to finally cut back the large climbing vining milkweed, Sarcostemma cynanchoides (Funastrum cynanchoides), by my front entry. Usually this is on  my December work list, but this year I’m a bit behind in the yard duties. Now this vine was way past its summer peak of luscious green leaf tendrils and cascading white flowers. Instead it was graced with brittle, dry leaves, a harbinger of its winter rest.  With our warm weather it wouldn’t be too long until a surge of new growth begins to appear.

This year the aphids were especially bothersome on the climbing milkweed and their honeydew was thick. Their oily stains were everywhere on the nearby wall and sidewalk. So I started pruning in snippets here and there since it was so messy. I always try to keep an eye out when cutting anything back – you never know what you’ll find. Sometimes what looks like the worst place anything could live is a secret cove. Even so I was surprised when I took a few snips and spotted the sun dancing off the gold of a chrysalis deep inside.

Now even more cautious, I continued to cut and look carefully. In just a few minutes I found this thin but late stage queen caterpillar, Danaus gilippus. It was amazing to think anything could still be alive in this clump of dead leaves, but there were a few inner ones still in marginal condition that appeared to be its food source. If I was going to cut this plant back I’d need a new game plan, so I moved the larva to one of the evergreen milkweeds in the back yard and watched it excitedly move to a fresh new leaf and munch. 

All in all I found five queen chrysalises and three caterpillars on this single climbing milkweed.  How did I know they were queen chrysalises versus monarchs? It’s all in the gold – you can learn how to tell the two apart in this photo link by Butterfly Fun Facts. This is the latest I’ve seen queen larvae on this vine (although I have seen larvae on evergreen milkweeds in small numbers in warm winter years in my yard.) 2013 was a warm year in Phoenix according to the National Weather Service so we may see other unusual activity as well. 

Queen butterfly, Danaus gilippus

Thursday, January 2, 2014

Monarch Butterflies in the Winter Desert

Monarchs in Scottsdale in December
Every winter provides a mixed opportunity for monarch butterflies in the lower elevations of Arizona. After the first week of December, monarchs lose their urge to migrate and tend to settle locally for the season. When temperatures remain warm well into fall as they have this year, there is ample opportunity for monarchs to complete their growth cycle and flourish. Since they are tropical insects they do not usually survive a hard freeze unless they shelter in a warmer microclimate. But they are known to not only survive but thrive with a light freeze. This year so far, the weather is creating an ideal environment and monarchs are flourishing.

An early freeze and daytime temperatures only in the 50’s for four consecutive days were risky for
monarch winter survival. Non-native milkweed and nectar sources showed evidence of light frost damage. Yet, despite this short term assault, temperatures warmed and vegetation once again surged in growth. Reports of adult monarchs and larvae began rolling in from the greater Phoenix and Tucson areas. So far information shows a mixed population of breeders and some monarchs that appear to be in reproductive diapause. Our record high of 82 on December 17 could possibly trigger breeding in monarch populations spending the winter in the area – or not.

Monarch larva in Scottsdale
Overwintering strategies in the Southern United States of the monarch population are not well known but several studies are underway. Most to date have revealed that monarchs are breeding and laying eggs on non-native Tropical Milkweed, Asclepias curassavica, which has naturalized in Texas and Florida and is present in limited gardens in Arizona. Native milkweeds in these areas have already senesced and Asclepias curassavica is the only milkweed present. But Arizona offers a unique opportunity to monitor monarch breeding during the winter months since we have several evergreen milkweeds that are always in good condition and available. Desert Milkweed (Asclepias subulata), Pineleaf Milkweed (Asclepias linaria), Arizona or Narrowleaf Milkweed (Asclepias angustifolia) and Asclepias albicans are growing in areas where monarchs have been spotted. They offer an opportunity to monitor breeding and egg-laying. In some garden areas, Tropical Milkweed, Asclepias curassavica, is also planted alone or away from our native milkweeds. This provides a unique opportunity to monitor the presence and absence of monarch larvae.

If you see adult monarchs flying or monarch mating, egg-laying, larvae or pupae, please let us know at the Southwest Monarch Study via email or on our Facebook page. Your sightings and observations help us all learn more about the monarch butterfly migration and breeding in Arizona and the Southwestern United States.