Sunday, July 28, 2013

The Baltimore Checkerspot Returns

A Baltimore Checkerspot Butterfly nectars on Indian Hemp
We've had our first good Baltimore Checkerspot season in at least 5 years. Lately They've been spotted in various meadows around the nature preserve. Its interesting how some species, like the Baltimore, can become so rare even though their available food supply (larval food plants) varies so little year to year. Turtlehead is the traditional food plant for the species and it has only expanded in the past 12 years - both on its own and due to our restoration efforts. 
Turtlehead is the traditional host plant of the Baltimore Checkerspot
Turtlehead occurs in wet meadows and along stream sides
The Baltimore also utilizes English Plantain as an adopted food plant. This alien weed is ubiquitous in fallow fields, suburban yards and so called "waste places". Though the ability to feed on such a prevalent plant could only be considered as good news, it still has not resulted in making the checkerspot very common.
The Baltimore is one of our most distinctive butterfly speices
Baltimores mating in one of the upland meadows

With the ability to inhabit both low land swamps (the domain of turtlehead) and dry upland fields  (where plantain often dominates), the Baltimore may be encountered in a range of diverse habitat settings. At the preserve, it has been the wetlands where they occur most reliably - and when the population contracts, it's most often the wetlands that hold the last remnant of the population.
A female Checkerspot with its abdomen swollen with eggs
The female lays her eggs on the underside of the Turtlehead leaf
The eggs are yellow or orange and are laid in a large cluster
Essentially, Baltimore Checkerspot Butterflies are tent caterpillars. Oh no! Not dreaded tent caterpillars. Unlike the Eastern Tent Caterpillars and the Forest Tent Caterpillars, the checkerspots do not defoliate forests. They make their tents around their perennial foodplants and have no reason to ascend into the trees.
The silk tent is woven around the Turtlehead plants
The early instar of the Baltimore larvae create the tent
Unlike most butterfly species that deposit their eggs individually on their host plants, Checkerspots lay large clusters of eggs on a single leaf. The young caterpillars feed together and collectively spin a large silk tent around the host plant. The tent offers them some degree of protection from predators - at least during the early period of their development. Ichneumon wasps patrol the outside of the tent and search for outliers that they can reach with their ovipositors and attempt to parasitize. When does a checkerspot  caterpillar appear to metamorphosize into a wasp? That's after its had an ichneumon egg laid inside of it.
These caterpillars are now large enough to live outside of the tent
The Baltimore caterpillar starts to shed its final larval skin
Later instars of the checkerspot caterpillars are more independent and they feed without the protection of the tent. Their larval skins are covered with hairs which make them  unpalatable to most birds and other predators. Baltimore chrysalises are small structures, but they are colorful and well bejeweled. Certainly it's a fitting packaging for one of our gaudiest butterflies.
The ornate chrysalis of the Baltimore Checkerspot
I was watching several Checkerspots as they raced around the meadow. Males were chasing off other males while females were scouting for their host plants. Some females had noticeably swollen abdomens and were presumably full of eggs, but the one that I followed appeared to be empty. She kept landing on turtlehead leaves, but although she went through the motions of laying, nothing was being deposited on the leaves.
Note the orange antenna clubs, eyes and legs
An explosion of orange - the Baltimore nectars on Butterflyweed
Nectaring on Valrian flowers
The males were mostly nectaring on Valerian plants. These tall non-native perennials superficially resemble wild carrots and parsnips, but unlike those common plants, Valarian is not in the parsley family. The plant has been expanding primarily in damp meadow habitat throughout the region. A decade ago we had only a few patches of it, now it is difficult to find a place where they are not represented.    

Sunday, July 21, 2013

The Plight of Bobolinks and Other Grassland Birds

The male Bobolink gives warning calls from a bush overlooking the meadow
In recent decades, in our region and generally in the northeastern US, grassland birds aren't fairing very well. Much of the agricultural land is now being planted with row crops like soy beans and corn and is in effect, no longer viable as breeding habitat.  Maintained hay fields are pretty much ideal for their nesting, but unfortunately, too often these fields are mowed too early in the season for the birds to finish their nesting cycle. In other words, the birds are unable to fledge young before their nests are destroyed. This phenomenon has made grassland birds some of the hardest to find species in the rural areas where they once thrived.
A group of male (Tom) Turkeys feed in a recently cut hay field
Savannah Sparrows are becoming less common due to early mowing
This year there was somewhat of a reprieve for a few grassland species that nested in local fields. The massive amounts of rain that fell during June (at the height of the breeding season) necessarily delayed the first cutting of many hay fields. This meant that the nests begun on time, most likely were able to produce young. That's assuming that parents were able to secure enough insect food for their nestlings, which is not always  easy during periods of persistent rain.
A Savannah Sparrow with a beak full of insects for its nestlings
Decades ago, the Eastern Meadowlark was a common grassland bird in the region
Savannah Sparrows, which seem to be the latest grassland species to suffer serious population declines in our region, did apparently manage to complete their nesting cycle in the hay fields just west of the nature preserve. This is the first time in years that I can say that. Bobolinks too seem to have been beneficiaries of the rains. 
A group a male Bobolinks gather in early July - they may be "refugees"
Hopefully, someday our grassy wildflower meadow will be used by Bobolinks
In recent years one of our preserve's meadows have played host to bobolink refugees. These birds were forced to abandon their nests once the tractors came onto their breeding grounds. The Bobolinks will not try to nest again, but will linger in the habitat for a few weeks before pushing into other areas with better food supplies. In only a month or so they’ll be starting to migrate south.
Gray-headed Coneflower begins to bloom in the wildflower meadow
As the habitat grows in it with bushes and small trees it attracts the Field Sparrow
Bobolinks still nest in the nature preserve's north field. This fallow field, which is only half on our property is just barely acceptable as breeding grounds for the Bobolink. The grass is giving way to goldenrod, asters and other tough stemmed perennials.  Certainly, the meadow as it is wouldn't even be considered viable nesting grounds by other grassland species. Most of them are much more particular than the Bobolink is about the make-up of the meadow's plant community.  
Increasingly, the Blue-winged Warbler is found in and around the Bobolink's field
The Rufous-sided Towhee is another bird that prefers brushy meadows
Now the Bobolink field is also slowly growing in with trees and shrubs. Every year there are more birds moving in that prefer brushier terrain to nest in. One of the Bobolink's new neighbors is the Clay-colored Sparrows, which were first identified as using this habitat only last year. This species along with the Field Sparrow, Blue-winged Warbler, Rufous-sided Towhee, Brown Thrasher and Alder Flycatcher will all benefit from the evolution of this habitat. 
The Clay-colored Sparrow is a very uncommon breeders in the region

Sunday, July 14, 2013

Turtle and Crayfish Refugees & Recent Butterfly Wars

Painted Turtles were common refugees following recent flooding
Following the floods of June and early July, some of our nature trails were transformed into streams and a few were even began to be used as avenues by wetland denizens. Most often I was finding turtles –most of which had presumably been dredged out of their lairs by rushing flood waters.
A painted Turtle swimming in the pond after its release
A Crayfish was a most unexpected traveler on the foot trail
The most interesting refugee was a large Crayfish that I noticed purposefully trotting down the trail. It was heading away from the traditional streambed, so I scooped it up and carried over to one of the ponds. I had previously done this with a half-dozen turtles and so I expected no intrigue.  I thought that it might be nice to video the Crayfish release –just a simple shot of it walking into the pond, but we both got more than we bargained for when a large Green Frog hopped out of the grass, intercepted and engulfed the crustacean in its gaping mouth!
Walking a few short feet to the pond - expecting no trouble
A Green Frog comes out of nowhere at nabs the Crayfish!
After the frog lets it go, the Crayfish, unharmed, settles into its new home
All 3 of us were surprised, including the Frog, who upon seeing me, immediately relinquished his prize and dove back into the water. The Crayfish, looking no worse for the experience, quickly sought refuge beneath a submerged bed of algae. Somebody got their money's worth from their suit of armor today!
A Banded Hairstreak - ready for battle
The rival Banded Hairstreak 
I've witnessed several pitched battles between butterflies in the past week. So much for the idea of butterflies as symbols of peace and coexistence. In fact many butterfly species can be quite combative.  
The Acadian Hairstreak has been uncommon at the Preserve in recent years
Most often male butterflies fight over territory and access to females. That was the motivation behind a battle between two male Banded Hairstreak Butterflies. It was a remarkable contest –2 nickel-sized butterflies chasing and colliding with each other for bouts lasting at least several minutes. I wondered how these minute insects could imbibe enough nutrients in order to allow such a sustained energy output, but they managed it. The next day, what I presumed were the same pair were at it again. Noteworthy is the fact that I saw neither contestant feed while I observed them on both days.

The Common Woodnymph Butterfly is well camouflaged on my camera bag
The purpose for the fight was to allow the victor exclusive rights to the territory --and the right to proposition any female that happens by. After his rival had vacated the area, the champion hairstreak seemed to briefly turn his attention to me. And yes he did try to drive me out of the territory, but fortunately for me, after a few minutes, I just merged with the terrain and became like an oddly shaped snag.
One of 3 Northern Pearlyeye Butterflies - just itching for a fight
A few meters away on the same trail, 3 Northern Pearlyeye Butterflies were fighting it out for possession of another prime piece of real estate. These guys are generally weaker fliers than the hairstreaks, and they did take more frequent rests. But their breaks were short, and soon all 3 were at it again. Since the Pearlyeyes are larger butterflies, it was much easier to follow all of the action in their little war.
Silver-spotted Skipper - the largest skipper in our region
The Little Glassywing is one of the "3 Witches"
We have 3 species of tiny dark skipper butterflies that are difficult to identify without getting a very close look at their wings, and since the 2 that were fighting it the meadow were a constant blur, I had little hope of getting a solid ID. These similar species are sometimes referred to as the “3 Little Witches” and they include the Dun Skipper, Little Glassywing and Northern Broken-Dash.
The Dun Skipper is most often the darkest of the 3
With wing shapes that resemble fighter jets, these diminutive insects can attain relatively impressive speeds; indeed, there is no lackadaisical fluttering around with these guys. As you might imagine, it’s hard to clock the speed of a darting insect that changes direction so frequently, but some estimates have them reaching around 30 MPH.
Eastern tailed Blue Butterflies have been more common lately
The skipper battle that I was watching was much more of a high speed chase, than a fight and I didn’t perceive any physical clashing. They would each alight briefly on meadow plants, but not long enough for me to positively identify them – perhaps tomorrow.
Baltimore Checkerspot Butterflies are starting to fly in the wet meadows 

Sunday, July 7, 2013

The Beaver Meadow

A new grassy meadow grows in the basin of a former beaver pond
Typically, when beavers abandon a pond, the habitat quickly regenerates into meadow. Grass seeds and the seeds of many other plant species begin to sprout in the rich silted-up soil, and within a few weeks a lush sea of grass grows where once beavers swam. The beaver meadow continues to evolve; that is as long as beavers refrain from re-flooding the area. The first year, not much diversity will be encountered and the meadow is dominated by grass and only a few other easily perceptible plant species, but only a year later, plant diversity increases tremendously and a wildflower meadow is born.
Blue Vervain plants grow plentifully in the beaver meadow 
The old beaver dam is covered with wildflowers
Undoubtedly, many of us recognize the good work that beavers do by creating water impoundments –and therefore wetland habitat for scores of other creatures, but few of us give them credit for their gardening work. Even without a beaver meadow, a beaver dam can act as a raised garden –hosting thousands of blooms along its span and providing food resources for hummingbirds and butterflies as well as a source of forage and bedding material for muskrats and for the beavers themselves.
Square-stemmed Monkey-flower grows in the new meadow
Swamp Candles (or Yellow Loosestrife) is in the Primrose family
When our old farm fields are left alone to evolve as they will, most in our region become dominated by goldenrods and asters as well as alien invasives like spotted knapweed. These plants generally attain a lock on the habitat and will not easily be displaced. They will certainly not be nudged aside by any less aggressive flowers. In other regions of the country, fire acts a disturbance factor in the environment as it clears an area of its dominant plants and allows a new plant community to develop. In our area, it's the beavers introduce the disturbance factor and are therefore the fathers (and mothers) of distinct meadow types in a given environment.
Yellow Moth Mullein is in the snapdragon family
Northern Willow-herb has very small blooms
The succession of plants that colonize the beaver meadow are surprisingly different than those which dominate our adjacent old fields. A lot of this difference is by chance, since it depends on what plant seeds are inherent in the given environment. But in my experience new beaver meadows even in the same area will not all develop in the same way. This may be explained by the varying prevalence and reproductive success of local plants on a year-to-year basis.
A Northern Pearly-eye Butterfly at the meadow's edge
The first Hickory Hairstreak Butterfly of the season
Plant make-up in the beaver meadow will continue to evolve as the years go by. The first 2 years or so, annuals and biennials might make up a greater proportion of the meadow's diversity, but in subsequent years, perennials will become established and eventually  dominate –at least up until the meadow is re-flooded and transformed into a pond once more.
Not a beaver meadow - but our main wildflower meadow, now dominated by spiderwort
A small proportion of the spiderwort flowers are pale blue
Oddly enough, this year the meadow that once was home to Sarah's Pond is now hosting an outstanding bloom of Moth Mullein. Just where all those Mullein seeds came from is a mystery. I've never seen more than a few of these plants in the surrounding fields for the past dozen years. It’s conceivable that these seeds, along with those from dozens of other diminutive species were there all along, lurking in the silt at the bottom of the pond –biding their time and waiting for their chance to sprout.
A buck lays down and remains partially hidden in a corner of the field

A Spring Azure Butterfly (very small) lands on my shoulder 
Blue Vervain, which dominated the beaver meadow last season is back again in a big way this year. The copious amount of rainfall that we've received in the last several weeks have suited them fine, and they are growing taller than usual, and mingling well with the tall mulleins.