Robber Flies

I took this series of photos one afternoon about six months ago during a time when I was experiencing internet connectivity problems.  The file has been stuck in my blog folder since then, along with several others.  I deleted the others, but I am such a fan of Robber Flies that I just had to make this post.  Resting on a leaf about half way down into the canopy of an herbaceous border sits this Diogmites species. 

Robber Flies are predators.  They spend much of their time sitting where they can watch for passing flying insects. I enjoy watching this species because its head is so mobile. It swivels its head in the direction of even the slightest bit of movement, which at some point always includes the photographer.

This slightly larger member of the Robber Fly group is a representative of the genus Efferia.  It came to rest on my hand while I was working in the field, which I hope does not give anyone the impression that I move so slowly while working that animals find me a convenient perch.  The end of the abdomen tapers down into an almost sword like appendage. Although it looks to be a formidable weapon, it is used as a tool for laying eggs deep into flower heads or other locations deemed suitable for growth of the larvae.

This is Promachus hinei.  Although it’s not the most common in terms of total Robber Fly numbers at Blue Jay Barrens, it is the most commonly encountered species of Robber Fly. Because of their large size and noisy flight, they are hard to miss when you happen upon them in the field. On this particular day, almost every individual I found was busily feeding, and several were feeding on somewhat unusual items like this paper wasp. When hunting, Robber Flies launch from a perch, grab an insect from the air, and return to a perch to consume their prey. The Robber Fly’s first action after a catch is to insert its piercing mouthparts into the body of the captured insect and inject a chemical relaxant that attacks the nerves and calms the prey. Along with the nerve agent is an enzyme that liquefies the internal body of the insect, so the robber fly can drink its meal.

To some, this may look like a love embrace. Unfortunately, that fly giving the big hug is not moving in for a friendly cuddle. 

These big flies will take any prey they can handle, even if it’s their own species.  That’s a male of the species making a meal of a female.  You can see his piercing mouthparts just below his front leg in a direct line with the grass stem beside his head. I hope next summer is another bumper season for Robber Flies.

Salamander Eggs

So far this month we’ve had 5.8 inches of rain, with rain falling more days than not since January 1.  Temperatures have remained above average.  High temperatures in the 50’s and 60’s Fahrenheit have been the norm so far this year.  It’s been a tough year for pinpointing when salamanders began showing up in the pond for their annual breeding frenzy.  All I can say for certain is that the pond was free of salamanders three weeks ago, and now the pond is full of salamander eggs. 

The frequent rains have kept the water level high and visibility slightly clouded, but it’s easy to see the masses of egg clusters clinging to plant stems scattered across the bottom of the pond.

I found this Jefferson Salamander during a break in the rain a couple of nights ago. 

This is the most common pond breeding salamander at Blue Jay Barrens, and the only one here that produces egg masses this early in the year.  In a month or two, Spottted Salamanders will enter the pond and leave their own egg masses.

Attached to the underside of a floating plank were these eggs of the Streamside Salamander.  This species typically places its eggs on the undersides of flat rocks in small headwater streams.  In situations where they utilize temporary pools, the eggs are placed on the undersides of any available surface.  Once it became apparent that Streamside salamanders were breeding in this pond, I adorned the deepest part of the pond with a variety of items suitable for receiving eggs.    I am assuming that these items are now sporting a nice covering of Streamside Salamander eggs. I’ll find out for sure when the water clears enough for me to see though to the pond bottom.

The Streamside Salamander eggs seem to be developing rapidly.  I suspect that warmer water temperatures have increased the rate of egg development.  This may increase the chances of the salamander larvae reaching their land dwelling stage before the pond water disappears for the summer.

Status of Girdled Trees Project

Back in May 2015 I girdled and applied herbicide to the large trees in this area in an attempt to create a grassland corridor between two areas of healthy prairie.  I thought it would be a few years before any of the killed trees began to fall.  Things are progressing much more quickly than I imagined.

In only a year and a half, about a third of the girdled trees have already fallen.  With one exception, all of the fallen trees have been Tuliptrees. 

Some of the trees dropped into the neighboring prairie.  Since this area is still being treated to eliminate invasive shrubs, I’ll remove the fallen trees to make it easier to find and destroy any invading sprouts.

The trees broke just above the girdle ring.  The girdling was done high enough on the trunk that a tall stump remains.  It’s best to leave the stump tall enough to be visible in the grass.  This way you are less likely to fall over or run your mower up onto the stump.

It looks as though the dead trees hosted quite a few wood boring insects.  I was surprised to see the extent to which the wood had been penetrated.

Woodpeckers appear to be taking advantage of the insect laden tree trunks.  I thought some of the trees were large enough to serve as woodpecker nesting sites, but I don’t think they are going to be standing long enough to serve that purpose.  I’m expecting this tree to fall soon.

In June 2016, about a year after being girdled, the Tuliptrees were still producing leaves on a few branches.  I was having some doubts that I had successfully killed the trees.

The trunks themselves gave some positive evidence that I was getting the desired results.  Impressive fungus growths suggested that decomposition was occurring beneath the bark.

A variety of fungus species were present.

I was impressed by the number of fungus species that were able to so quickly take advantage of the recently killed trees.

This area will soon be dominated by tall grass, but it won’t be without a few trees.  I have left several young Blackjack Oaks, Quercus marilandica, to grow among the grass.  Blackjack Oaks have a special relationship with several prairie invertebrates, and are well worth saving.  There won’t be enough trees left to hinder the growth of the prairie grasses, but there will be enough to enhance the quality of this small area.

You can read about the original girdling project by clicking HERE.  

2017 Blue Jay Status

January weather typically includes a bout of cold temperatures and snow cover. These conditions bring an increase in activity at the Blue Jay Barrens birdfeeders and give me an opportunity to assess the local Blue Jay population.

Blue Jay numbers are running at about their normal level this year. Except for one or two birds that have a distinctive marking or unique behavioral trait, I can’t tell the individual birds apart, so I don’t know for certain how many are year-round residents of Blue Jay Barrens and how many have just moved in for the winter. The general behavior of the flock makes me think that the majority of individuals are here all 12 months of the year. In particular, I don’t believe that a new arrival would automatically know to sit in the apple tree and yell when the feeder goes empty.

As always, the almost constant movement between the feeding area and the nearby trees makes it nearly impossible to get an accurate count. I spotted 29 Blue Jays in the previous photo, including the one in the air. I know there were at least 47 here at one time, but at that same time I could see several more moving in the trees at the edge of the field a few hundred feet away.

The feeder on the post contains black oil sunflower seed. The area at the base of the tree in the upper right-hand corner of the photo gets a few cups of cracked corn scattered out each morning.

Second to the Blue Jays in producing consistently high numbers in the feeder area are the Cardinals. In between trips to the feeder, the Cardinals tend to hang out in the dry stalks of Giant Ragweed and Wingstem adjacent to the feeder.  The smaller feeder visitors also seem to prefer this area for feeding and loafing. The large crop of seeds produced by these plants has now been nearly consumed.

The tall plant stalks have been battered by rain, wind, and snow, but they continue to remain upright.

It’s not uncommon to count 30 or 40 Cardinals in the feeder area at one time. Most take their seed from the ground instead of directly from the feeder.

Mourning Doves typically arrive a couple hours after sunrise. There are usually 25 or 30 individuals in this flock.

Most of the doves in the area spend the winter gleaning seed from nearby harvested crop fields. A deep snow can make that source of food inaccessible, and the result is a substantial increase in Mourning Doves at the feeder.

These two Blue Jays demonstrate how so much sunflower seed gets on the ground beneath the feeder. They scrape seed up and over the edge of the feeder tray until they find just the seed they want. This also explains why my feeder sometimes so rapidly runs out of feed. I thought for a while that they were searching for the few shelled seeds that could be found in the mix, but that didn’t turn out to be the case. When they start to load up with seed, it’s just the standard seed in a shell. Maybe they just want to be sure that their friends down below have plenty to eat.

Draba cuneifolia

Is it too early in the season to begin talking about Draba cuneifolia?  I didn’t think so.  We are into the third growing season for Draba planted in one of my garden beds.  Classified as a winter annual, this plant grows through the winter and produces flowers and seed the following spring.  The plant then dies, leaving a scattering of seeds to produce the next generation. 

Draba cuneifolia plants remained alive in this bed until mid-June 2016.  Seedlings began to appear in late July.  The profusion of plants now growing in the bed points out the inefficiency of my seed collection methods.  Plants cover the top and sides of the bed, are growing in the walkway between beds and have shown up in neighboring beds.

New plants emerged from the end of July through October.  There are probably still new plants appearing, but they are hard to notice among the mass of plants that are already there.

In order to survive the winter, these plants must quickly get a root down below the frost line.  Since they grow primarily in areas of bare soil, they are in danger of being pushed from the ground through the process of frost heave, which occurs when soil alternately freezes during cold nights and thaws during the day.  Having their roots penetrate stable soil anchors the plant and keeps it in its proper place.  These small plants can produce some extra long roots.  I once saw some plants that had their roots exposed when heavy deer traffic caused part of a bank to break away.  One plant had 15 inches of root showing.

Those plants that began growing in July have reached an impressive size.  These are the plants that will produce masses of flower stalks next April.

Remnants of last year’s plants are still evident.  These spindly stalks, along with the dried Draba leaves, did a good job of protecting the site from erosion through the summer.  I once perceived the appearance of Draba cuneifolia to be an annual event that passed so quickly, it could easily be missed.  Two decades of observation has caused me to alter my perceptions.  I’ll admit that the blooming season can sometimes be short, but I have seen years where blooming plants could be found over a two month period.  It seems that the living plants can be found during a ten month period each year, and their skeletal remains are around during that two month break.  Now that I know what to look for, I can check on my little friends at any time of the year.

Toad Pool 2

In November, I managed to get some more work done on Toad Pool 2, my second attempt to create more toad breeding areas at Blue Jay Barrens.  Frequent rains during the first part of summer kept the soil too wet to work.  Weather conditions went to the other extreme during the last half of summer, causing the soil to be too dry to compact.  Finally, a perfect balance was reached on November 17, so I continued with my construction activities.

My construction techniques are fairly simple.  I use a tiller to pulverize the soil to be excavated.  The loose soil is scooped out and deposited to form a dam on the downhill side of the proposed pool.  The soil is built up in successive layers of an inch or less of soil.  Each layer of loose soil is fully compacted before the next layer is added.  The idea is to end up with a tightly compacted barrier to keep water from leaking out of the filled pool.

The soil on this site has no shortage of rocks.  Plowing activities that occurred several decades ago moved rocks to a higher position in the soil profile.  On this location, the plows must have been dragging very near the top of the bedrock layer.  During my excavation, I have encountered a couple of bedrock areas that were pulverized by the ancient meteor impact to a condition nearing small gravel.  This makes me wonder if the site will be capable of maintaining water for the period necessary for a batch of toads to be successfully raised.

I decided to finish this year with a pool that is smaller than planned.  I’ll see how well it holds water next spring and then decide if it is worth the effort to enlarge the pool area.  If it doesn’t hold water, I’ll then consider the option of installing a pond liner.

On November 30, a half inch rain put the first bit of water into the pool.

Another half inch of rain a week later brought the pool to within a few inches of being full.  There are three seasonal springs that feed into this area through the winter and spring.  With luck, they will produce enough water to offset any leakage in the pool.

On December 17, a 2.5 inch rain filled the pool.  Now it’s just a matter of waiting to see what happens.

Toad pool 1, about a quarter the size of the new addition, has proven able to maintain water long enough to raise a crop of spring breeding amphibians.  Unfortunately, the first pool is now four years old and I’m still waiting for the toads to discover this gem of a breeding area.

Invasive Control - Sprouts from Bird Droppings

I believe I have reached the maintenance stage in my efforts to control invasive shrubs at Blue Jay Barrens.  After eliminating all of the large, fruit producing specimens, I spent a couple of years dealing with masses of root sprouts surrounding the dead stumps.  Now I deal primarily with newly arrived two to three year specimens.  The Autumn Olive in the photo above shows what I typically find during my searches for invasive shrubby species.

Birds are the primary transport mechanism bringing seeds of invasive plant species onto the property.  Seeds passed through the gut of a bird arrive via bird droppings.  The bird’s digestive process softens the hard seed coat, making it a high likelihood that the seeds will germinate come the next growing season.  Seedlings arising from this type of process are usually found growing in a closely packed clump only a few inches across.

A typical clump consists of 8 – 12 individual plants, identifiable here by the light colored stumps that remained after the tops were removed.  The seeds are most often deposited in the fall.  By the time the seeds germinate in the spring, they have been separated slightly through the action of the soil fauna feeding on the non-living portion of the bird dropping, along with climatic factors such as rain, wind and frost-heave. 

I sometimes find first year seedlings, but they are hard to see because their height rarely exceeds a few inches.  It’s more usual to discover the two or three year old clumps.  A plant that reaches only six inches one year can easily grow to three feet by the following year. 

The seedlings within a clump are in fierce competition with each other.  Only those that make the most efficient use of the resources within their root zones will survive.  Within each clump are one or two stronger stems that overtop the others.  Stems on the outskirts of the pack frequently grow horizontally along the ground and form roots away from the group.  Here they can develop with less competition and increase their chances of survival.

The seeds in this group failed to disperse much beyond the limits of their original deposition.  Horizontal growth was the only way for many of the plants to access sunlight.

I don’t know how many thousands of seeds are brought into Blue Jay Barrens by birds each year.  It’s usually not difficult to find fresh seeds on the ground in areas frequently used by birds for feeding, roosting or loafing.  A good example is this pan of fresh water that I keep near my bird feeding station.

On the deck beside the pan is an assortment of seeds left behind by birds coming in to drink or bathe.  From late summer through mid-winter, new seeds are added daily to the collection.  When I empty the old water, done once or twice each day, there are always a few seeds in the pan.  Not all of these seeds come from invasive species.  The majority are Eastern Red Cedar, a native that happens to be a threat to open grassland and prairie.  There are enough invasive seeds though, to make alien shrub seedlings a permanent fixture here.  Fortunately, there are no more invasive shrubs at Blue Jay Barrens that are mature enough to produce fruit.  I am no longer contributing to the problem, I am just dealing with it.