Monday, July 14, 2014

Monarch Butterflies

The spring Monarch Butterfly migration passed without a single Monarch sighting at Blue Jay Barrens.  My earlier disappointment has been abated with a summer season Monarch count surpassing any in recent years.  The Milkweed stands are receiving frequent visitations from this colorful butterfly.


Of course, this is the real reason for maintaining patches of Milkweed plants.  Monarch larvae are Milkweed eaters.  Recent declines in the Monarch population make it more important than ever that this plant be readily available.


Having Milkweed plants snug up against the house makes it easy to monitor the progress of leaf eating insect larvae.  Because of a beating they took during a spring thunderstorm, a few of the plants are unable to maintain an upright position.  Most, however, are standing tall, even though a few needed some propping up and stem support to achieve this condition.


Landscape designers probably wouldn’t recommend crowding the entrance to your home with seven foot tall Milkweed plants.  I would agree, especially when the flower visiting bees during the day or moths at night get sucked into your home every time you open the door.  This Milkweed thicket was not actually intentional.  A single plant that became established beside the water garden was allowed to remain.  Within a couple of years that one plant became two dozen.  For the benefit of the Monarchs, I let them remain.  I must admit that I am also fascinated by the vast array of insects attracted by these plants.


I’m currently finding larvae of all ages.  The youngest are just beginning to show their characteristic black filaments.  Small larvae are easiest to see by looking from below a sunlit leaf. 
 

Midsized larvae show short stubs where the long black filaments will eventually be.  Larvae can also be located by examining holes in the leaves.  Feeding sites are more regular in appearance than hail damage left by the early storm.


Leaf damage causes the Milkweed plant to ooze its thick white sap.  The sticky sap can make it difficult for the larva to feed.  The larva overcomes this obstacle by systematically severing the veins leading to the leaf, this stopping the flow of sap.


In small leaves, the midrib is often cut to halt sap flow to the entire leaf.  On larger leaves, a series of lateral veins might be cut as seen here.


Once the sap stops flowing, eating commences.


The larvae seem to practice an eat-and-run technique that minimizes time spent in any one location.  A section of leaf is consumed and then the larva moves on to another location.  Many predators are attracted to leaf damage in search of prey.  Despite the Monarch’s unpalatability due to accumulating toxins from the Milkweed plant, some predators have to learn the lesson first hand to the detriment of the larva.  Even though they are bad to eat, the best survival strategy is to avoid the predators.


The excess rainfall experienced this spring has really benefited the Milkweeds in the field.  The plants bloomed early and are continuing to produce new flower buds.


This large stand of Purple Milkweed continues to attract Monarch Butterflies as well as other insects dependent on the Milkweed plant for their survival.


It appears that Blue Jay Barrens will contribute a large number of Monarchs to the masses that will make their way south later this summer.  I just hope that conditions at their wintering grounds are favorable for the species continued survival.

Monday, July 7, 2014

Edwards' Hairstreaks 2014

The first week of July seems to be the peak flight period for Edwards’ Hairstreak Butterflies at Blue Jay Barrens.  Because of this, it has become a Fourth of July Holiday tradition for me to take a little time to survey the Edwards’ Hairstreak population.  Of course, I also look at many other things, but for this one outing my priority is to find the hairstreaks.


I had plenty to look at.  There were dozens of Edwards’ Hairstreaks nectaring on the Butterfly Weed.  I’ve never before found so many occurrences of multiple hairstreaks on the same flower clusters.


In order to have Edwards’ Hairstreak butterflies, a site must have young oak trees to provide food for the larvae and it must have Allegheny Mound Ants, an ant species that acts as guardians for the butterflies during their early developmental stages.  Click here for more details on Edwards’ Hairstreaks at Blue Jay Barrens.


When I first discovered Edwards’ Hairstreaks at Blue Jay Barrens twenty years ago, they were located in only one small area near the center of the property.  Since that time, I’ve been encouraging oaks to colonize areas near the large ant mounds.  Young Black Jack Oaks seem to be the preferred host species, so these trees are given priority in all management activities.


I was particularly impressed by the butterfly numbers at this site.  It was nearly ten years ago when I discovered a single Edwards’ Hairstreak in this small opening.  Now there is a thriving population.  Oaks and anthills indicate that the hairstreaks are a possibility.  Add in a clump of Butterfly Weed and you have the perfect opportunity to observe this butterfly.


I’m not sure how to sex these butterflies, but I would think eggs each time I saw an individual with such a robust abdomen.  I felt like shooing her off the flower and sending her over to the tree to deposit those eggs before one of the many flower lurking predators made a meal of her.  I always have to remind myself that wild animals probably know more than I do about what they should be doing to insure future generations of their species.


A few of the hairstreaks looked like they were freshly emerged, but most had lost some of their luster and were looking slightly worn.  Damaged wings suggested probable encounters with predators.


A couple just looked downright battered.  It looks like this one has had quite a time, but it proved to be a strong flier despite the wing damage.


It’s always encouraging to see positive results from your management efforts.  I’m hoping that the Edwards’ Hairstreak population at Blue Jay Barrens continues its expansion.

Friday, July 4, 2014

Vultures

A young raccoon got run over on the road in front of our house sometime early Wednesday morning.  I found it and relocated it to the backyard near the edge of the field, in hopes of attracting some vultures.  I then came into the house to clean up and change into cooler clothes.  As I headed back to the bedroom, I glanced out the window to see why the Blue Jays at the feeder were making so much noise.  Turkey Vultures had already arrived and were using the woodpecker tree as a perch to look over the potential meal.


Most birds aren’t bothered by my watching from behind the window glass.  The Turkey Vultures not only noticed me, they were uncomfortable with my presence.  In a great flapping of wings they left the dead tree stubs …


… and moved to the barn roof.


They landed with their backs to the offered food item and stretched their wings out in the morning sun.


It was not until I finally got to the back window that I found out that a Turkey Vulture had already found the raccoon.  I had left the carcass in the short grass, but the vulture moved it down into a more secluded location.  It fed undisturbed for several minutes.


Then a Black Vulture showed up. 


The Black Vulture took possession of the raccoon.  The Turkey Vultures stayed close, but didn’t try to reclaim their meal.  Each time a Turkey Vulture moved too near the raccoon, the Black Vulture would take a step forward and the interloper would back off.


After a few minutes, the Black Vulture moved the carcass back out into the short grass.  I think the tall grass was blocking its view of the Turkey Vultures and it relocated to an area where it could watch and eat at the same time.


Black Vultures historically ranged south of Blue Jay Barrens, but they have been gradually increasing their range northward.  While they were once a rarity here, they have now become a regular feature.


The Black Vulture finally became the undisputed owner of the meal.  Most of the Turkey Vultures took off to hunt for food elsewhere. Except for one that parked itself in front of the Black Vulture and just watched it eat.


The quiet intimidation must have worked, because the Black Vulture finally flew off.  The persistent Turkey Vulture then spent a quiet few hours finishing off the raccoon.


By early afternoon the Turkey Vulture had completed its meal.  It took wing and disappeared.


Nothing left but skin and bones.  It’s amazing how efficiently these birds can strip a carcass of its meat. 

Wednesday, July 2, 2014

Squash Vine Borer Moth

In my vegetable garden, I have a large clump of Butterfly Weed that brings in a wonderful collection of nectar consuming insects.  I had my face tucked in close to the bright orange blooms when a wasp-like insect nearly grazed the tip of my nose.


I pulled my face back a bit and watched the little flier spiral its way into a landing on one of the flower clusters.  At rest, this insect certainly displayed some hymenopteran qualities, but it was certainly no wasp.


Closer examination shows it to be a moth, a Squash Vine Borer Moth to be exact.  This is one of the few day flying moths.  It is also a wasp mimic, meaning that the physical appearance of the moth has a resemblance to a wasp.  This mimicry affords the moth some protection from predators that would avoid tangling with a stinging wasp.


A search of the flowers revealed several of the moths mixed in with the crowd of truly stinging insects.


The hind wings are clear, which emphasizes the dark forewings.  When outstretched, the wings resemble the raised forewings of an angry wasp.  The hind legs bear large tufts of dark reddish-orange hairs.  When in flight, the moth carries the legs below the body and it looks very much like a wasp carrying a caterpillar.


The antennae with their curled tips even look like the antennae of male polistes wasps.  This is a very interesting moth in terms of both form and behavior.  The name Squash Vine Borer says all that most people need to know about this moth.  The larvae live their lives inside the stems of squash vines and their relatives, ultimately bringing death to the plants.  Because of this, most people’s interest in the moth doesn’t stray far from how it can be eliminated.


There’s a good reason why so many of these moths were visiting this particular patch of Butterfly Weed.  There are some nice summer squash vines growing just a few feet away.  I may lose a vine or two to the moths, but it’s not really a hardship.  I’ll trade a couple of vines for the experience of watching the adult moths.  Besides, I love to eat fresh squash and start a few new plants every couple of weeks right into summer.  The adult moths are only around for a short time, so they won’t infest my later plantings.  I’ve never had them lay eggs on all of my vines and there has never been a summer when I couldn’t go out at any time and pick some fresh squash.

Monday, June 30, 2014

Fall Webworms

Prairie Dock doesn’t typically suffer much insect predation, so a clump of brown leaves in the Prairie Dock patch easily caught my attention.  I arrived at the affected plants to find a hoard of Fall Webworms consuming the thick, leathery leaves.


I’m used to seeing Fall Webworms at Blue Jay Barrens, but they have always been on trees or shrubs.  There don’t seem to be many tree species that they won’t eat, so I guess it’s not unlikely that there are many plants they would find palatable.  If that’s where the female laid her eggs, the larvae really don’t have much choice other than eat or die.


Fall Webworms are communal feeders that build a network of webbing that covers their feeding area.  New silk strands have been stretched over the midrib of the dock leaf to offer protection to those caterpillars heading out to begin feeding on a new section of leaf.


I think this is the webworm equivalent of painting yourself into a corner.  It won’t take long to eat this small edge piece.  Then it will be a long trek to the other side of the leaf to find some more green.


As the name suggests, Fall Webworms are normally encountered towards the end of summer.  In Ohio, this species can produce two generations in a summer, especially if warm temperatures arrive early in the year and hasten the spring emergence of the adult moths.  This year we seemed to shift from winter directly into summer, with little transition.  Snow fell on April 15 and that was the last time we had any freeze or frost.  By April’s end the temperatures were in the seventies.  Any species whose development was triggered by temperature was quick to emerge.


Several of the webworms didn’t remain within the community.  Bunching together is supposed to afford some measure of protection from predators.  Maybe predators are more attracted to the mass of potential prey items and fail to recognize these lone individuals.


When I checked back a couple of days later, the webworms were gone.  I looked around, but couldn’t find them anywhere nearby.


All they left behind were shed skins and frass caught in the old webbing.  Fall Webworms typically leave the webs and go to the ground to pupate, but I wouldn’t think they would do that immediately after casting off their old skins. 


The following day I found several individual webworms.  These were all the next size up, a little larger and hairier than what I had seen on the Prairie Dock.  Some were on the ground and others were munching on various plant leaves.  Perhaps there is some type of dispersal that takes place prior to pupation, so the pupae aren’t all confined to the same small area.  I’ll have to pay attention when more of these guys show up later in the summer.  Maybe I’ll learn whether or not this is typical behavior for the species.