Saturday, September 18, 2010
After a couple weeks of nonstop eating and growing, during which they shed their exoskeletons several times, they secure their posteriors beneath an overhanging stem with a silky substance. Dropping their heads, they assume a position in the shape of the letter "J." Within 24 hours, the caterpillar convulses and the exoskeleton splits open and falls away a final time, revealing a chrysalis of green and yellow, still ridged with abdominal segments. Soon, these ridges smooth away, and and the chrysalis becomes a pendant of opalescent pale green, studded with tiny gold jewels. The black stem is called a cremaster. Using a microscope one can see that the topmost end of the cremaster is composed of many tiny protrusions topped with knobby hooks. They appear to attach to the strands of the silk in much the same fashion as the human invention of velcro. After about 10 days, the chrysalis membrane becomes transparent. The body and wings of the adult butterfly can be seen inside, appearing almost completely jet black, with the exception of the deep orange pattern of the wings. The swirling shapes remind me of an Art Nouveau design of tree limbs silhouetted against a blazing sunset. I have yet to catch the exact moment of emergence. I think they wait until I leave the room! When I return there is the fresh, rather droopy winged adult, clinging to the remnant of it's casing. Over the next couple of hours, the Monarch balances delicately on four legs, turning itself from side to side, flexing its wings, unfurling its proboscis and wavering its front legs. Monarchs belong to a class of butterflies known as brushfoots ( Nymphalidae). These butterflies do not walk upon their furry front legs, but hold them flexed and close to their thorax. As the internal fluids transfer to strengthen and rigidify the wings, the body slims. Once during this process, I witnessed a drop of deep red fluid fall to stain the table beneath. Finally the wings are laid open in full color and shape. They slowly open, close, open, close, then suddenly take a maiden flight. The Monarch remains rather sluggish and calm for a while, enough time for me to take it on my finger and release it in a field tall with goldenrod blossoms. The butterfly shown below is a female. The wing pattern of a female has thicker veins of black than a male and lacks small black dots on the hind wings. Entomologists believe that the black dots on a male are vestigal organs. Evolutionary precursors of the Monarch emitted pheremones to scent pouches to lure females for mating. This generation is the last of the summer. The late summer Monarch butterflies in the eastern U.S will participate in a mass migration of 1000's of miles to a special place in the mountains of Mexico. There they will overwinter together in clouds of fluttering wings, clinging to the trees. The people who live there hold a festival each year to celebrate the return of the Monarchs. Traditionally, the Monarchs are believed to be the spirits of the people's ancestors.
In the spring, those Monarchs who have survived the winter will mate and begin the northward journey, laying eggs, then dying. The generation from these eggs will hatch as caterpillars, metamorphose into adults, continue northward, again mating and laying eggs, then dying. By the third or fourth generation, the butterflies have reached their northern terminus and the summer is ending. They must return to Mexico, a place they have never seen, to begin the cycle anew or perish. How do they do it? No one knows.
Thursday, July 22, 2010
Wednesday, July 14, 2010
In bed all day hoping to elude the symptoms of a virus. I want to join 19 other people who reserved a spot to accompany Steve Huy, a bander of saw-whet owls to his mist net site. We convene at 9 PM. Feeling better I make a cup of black tea at the last moment to sustain me and rush out to the car, only to find that my kitchen clock has betrayed me and I'm already late to meet the others at the commuter parking lot. With my cell, I ring Carolyn, the organizer of these once-yearly jaunts, for directions to the site.
I've worn the recommended boots, scarf, gloves and jacket. I later learn that in the past some women have shown up in high heels! The night is cool, the sky dark enough to see many stars as I travel into the lesser developed south county. The shape of South Mountain crouches blackly to my left. Monument Road twists and turns up the mountain, round and round, up and up. The turnoff is onto a narrow blacktopped lane that continues steeply upward, weaving in and around trees. It goes on for some time, and just as I seem to be cresting the mountain, and see lights blinking in the valley below, I run smack into the butt ends of cars huddled by a utilitarian shed. A communications tower erupts on top, silhouetted against the starry sky.
The second I open my car door, I hear a very loud sound piercing the darkness. It sounds like the friction of large rhythmically moving mechanical parts. But the irregularity in frequency and the varying duration of each shriek makes me think of a neighbor's dog whose vocal chords had been surgically altered to eradicate an obsessive bark. Only in this case something has gone terribly wrong. The noise is that much more affecting due to the lack of information I'm receiving from my favored sense of sight. I later learn that this sound is a recording of saw whet vocalizations blaring at high decibels from a speaker by the mist nets further into the woods. Supposedly the owls come to investigate the "intruder" to the territory.
Carolyn greets me with a flashlight and we stumble to where Steve is speaking about saw whets and his project. As shadowy figures we huddle by a security fence. Steve tells us that before the banding project it was thought that saw-whets numbered only in the hundred thousands, but now are believed to be in the millions. They are very small owls, maybe 5 inches--in response to a question about their size, Steve says he doesn't keep that information in his head because it is in books, rather the "owls fit in my hand." He says that although the males are smaller than females, there is no easy or quick way to identify an owls sex, but he has banded several thousand owls now, and so usually has a general impression of an owl's sex based on his accumulated experiences.
Two shorter individuals in the front of the group ask questions and I recognize their voices, both fellow WV Master Naturalists. From their profiles, I see Carrie's ubiquitous baseball cap, and Ursula's fluffy hair cut--she is not a wearer of hats. My eyes slowly adjust to the faint light--from the stars, nearby "light pollution," and a just rising waning moon--enough to make out their facial features. At this level of light I see in monochrome. I read that owls I have have many more rods in their eyes than humans, so not only see much better in dim light, but in color too!
The question of the utility of banding saw-whets is questioned since they are so "plentiful." He explains that the well-being of saw-whets reflects the well-being of the boreal forest, and our ecosystem as a whole. Predators, including birds of prey such as the saw-whet, are at the top of the food chainand ecological disruptions often first present themselves at that level, since toxins accumulate as they rise through the food chain. Most of us have heard of the endangered falcons and other birds due to DDT use and the resulting thinning of their egg shells.
Steve says saw-whets travel in spring to breed in the boreal forests of Canada and migrate south in the fall. Those northern forests are crucial to a healthy ecosystem and the life cycles of many other birds as well. The boreal forests of the world are much vaster than the earth's rain forests. They are being diminished by the lumber industry and by climate change--as we lose the freezing temperatures, and the duration of the freezes in the north. Wood boring beetles are not being controlled by these seasonal changes, and so they proliferate and take the lives of more and more trees, reducing habitat for breeding birds.
Finally it is time to check the mist nets! The recording has been screeching away for an hour. We troop in the dark down a path. A sign in the stern wording of a government agency warns against tampering with the nets. I had never seen a mist net and always wondered what it looked like. Saw-whets are relatively low fliers. A series of poles rise to maye 8-10 feet at most. The poles are spaced about 12-15 feet apart. Each net is about 8 feet tall, but loops up at the bottom forming a trough. The bird flies into the upper part of the net, then falls into the trough, and is secured. Two or three horizontal swaths of netting are stretched between the poles to form tiers of alternating netting and troughs. The line of netting extends 50 or more feet in one direction with another line jutting off at an angle midline.
We take care not to entangle in or damage the netting as each net costs $500-600. The holes in the net are as large as quarters--surprising since I envisioned a mist net as being very fine. The threads in the net are indeed very fine, and tension placed on the net is very loose. I can see how a bird could fly into it, be caught up, and not harmed. Close by the nets, the owl call is deafening. Ursula, shouting in my ear, confides that she purposely left her hearing aid at home.
There are no owls in the nets, Steve announces so we troop back to the security fence for more waiting. It occurs to me that we are like well-meaning spiders awaiting prey. What is the word for attributing animal behaviors to humans?--a reversal of anthropomorphism.
Ursula tells me she has gone on owl prowls twice before. She describes Steve placing the little owls in mesh envelopes that hug them closely as they await banding. The owls do not struggle but calmly submit to the banding process. She describes them as beautiful and adorable, without tufted ears as horned owls have, but with facial disks like barn owls. Ursula, Carrie and I trade wildlife stories amidst other groups chatting in the dim light of the crescent moon. One couple lights up an iPhone looking at birding info and listening to bird calls--at first. Later I hear canned laughter coming from the device. The glow from the digital screen lights up their faces and distracts my gaze from the moon and stars.
Ursula confesses about driving to a Christmas bird count one year and an owl flying into her windshield. She stopped and picked up the dead owl, placed it in her car and took it to the birding group to share as found on the roadside. She did not tell that she herself had been in the moving vehicle that killed it. She tells of meeting Scott Wiedensaul when he came to a friend's home to band a species of hummingbird unusual to this area. She says he is a very nice, unassuming man despite his fame as an author. We share a chocolate chip cookie I brought and Ursula wishes for ginger snaps and hot chocolate.
Time to check the nets again. The moon is now high in the sky. We again trundle down the rocky path with our flashlights but the verdict is no owls tonight! It is 11 PM and I have reached my limit. We return to the cars and two groups leave. A few other folks remain, perhaps to wait longer for the owls to make an appearance. I am somewhat disappointed after having waited two years for this opportunity. But as a dirunal animal, I enjoyed the novelty of a noctural foray and the company of other nature lovers. It is said we must take on the characteristics of the creatures we study and want to commune with. To study nocturnal predators, we go out at night, we wait, we cast nets, we use lures and mimicry, we boost our sight with artificial light, we dress for the weather and terrain. Perhaps I will have better luck next time if I add more meat to my diet.
Tuesday, June 8, 2010
It was such a beautiful evening, calm with slowly drifting fluffy white clouds in a robins' egg blue sky. I took a walk around the nearby lake, mostly looking for ferns. I spied an overturned, collapsed canvas camp chair that some one had forgotten. I turned it over with a mind to sit down and watch the sun set over the lake. Fortunately, one leg was broken so I slowed down enough to see what looked like a female Black Widow huddled in the middle of the canvas next to her web. I enjoyed the little shudder of danger she evoked.
Black widows (Latrodectus mactans) are pretty intimidating even at only 1/2 inch long. The contrast of the red on the swollen black abdomen shouts "beware!" The only other time I had seen one was in California and I believed they were not as prevalent in the more humid Eastern climate. They do prefer warm climates, but can be found as far North as Oregon in the western U.S and New York in the east.
L. mactans is the largest and most notorious of the spiders known as Cobweb Weavers. Species in this group are found worldwide except in the colder latitudes. All are poisonous. The Black Widow has a red hour glass on the bottom of her abdomen. Since this spider's hour glass is indistinct or broken up, and it's abdomen actually more dark brown, I believe it may instead be a Northern Widow (Latrodectus variolus). Both species live in this area. Black Widows are often found near houses, outhouses, dumps and trash heaps, usually under objects, as this lady was. Northern Widows prefer undisturbed woods, stumps and stone walls. There are also Brown Widows and Red Widows.
Most spiders do not readily bite, unless seriously provoked. According to The Golden Guide of Spiders and Their Kin, if you receive a bite from a Black Widow you will likely not even notice it -- at first. But as the venom circulates in your bloodstream, you will experience abdominal pain similar to appendicitis, as well as pain in the muscles and soles of the feet. Saliva flows then the mouth becomes dry. You sweat copiously while your eyelids swell. After several days of agony, you will recover, most likely.
This spider had certainly captured my attention. I was ensnared not by it's web but by the prospect of a comfortable seat, and then mesmerized by its deadly aura. I left the spider unmolested, the camp chair turned upright, it's broken status obvious to any other human roaming that wooded, rocky part of the lake shore. I expected the spider to find another place to hide now that it was exposed to the light and weather.
Monday, March 8, 2010
Tuesday, February 2, 2010
I realize I tend to dismiss white tails as not worthy of my attention due to the overpopulation and frequent sightings. I am upset by the damage to formerly favorite places like nearby Catoctin Mountain National Park due to over browsing. Perhaps too it is a way for me to cope with the reality of all the hunting that goes on each fall—a way to distance myself. So I’m writing this post to correct my prejudice and teach myself something about these animals.
Once can imagine the ancient predators of these deer —cougars, wolves and indigenous human tribes. But they were extirpated from these parts--not all that long ago. Bear still live here and coyotes have arrived from the west but these animals can only take down a young fawn or perhaps an adult deer impaired with an injury or illness.
I am learning to respect hunting as a tradition, especially when the meat is preserved or eaten and other parts of the animal utilized. (Click here for a fascinating article about different traditional uses of parts of the deer.) From a naturalist standpoint, I know the deer population needs controlling so they don’t completely decimate the environment and I consider it potentially a humane activity.
I dislike it when I come upon the leavings of a slaughtered deer ditched illegally along the roadside or in a field, as Squirrel and I did on the Eastern Shore of Maryland this past fall--right at the entrance to a wetlands nature preserve. Disposing of deer carcasses in this way is a serious threat to human health especially if near water, and it also endangers the deer themselves because it can spread Chronic Wasting Disease, a serious problem in other states, but which I believe has not yet surfaced in Maryland. Deer carrion is a source of food for scavengers like vultures, hawks, eagles, and foxes.
I can hardly think of deer without remembering the impact of reading Felix Salten's books as a child. Many people are surprised to learn that the character Bambi was not an original creation of Walt Disney’s. Felix Salten was a highly successful and prolific author in Austria. His book Bambi: Eine Lebensgeschichte aus dem Walde was published in 1923 . It is a "coming of age" story about a young male roe deer. In 1928, the English translation, Bambi: A Life in the Woods was a Book of the Month club sensation in the U.S.
The Salten family was Jewish; in 1936 Adolf Hitler had Salten’s works banned. Salten and his family left Austria (which by then had become part of Germany) in 1938, settling in Switzerland. In 1939 he published a sequel -- Bambi’s Children: The Story of a Forest Family, which details the deer's struggle to survive while being pursued by "the thundersticks."
Now that I know Salten’s back story I will need to go back and re-read Bambi's Children--it must reflect some of what was happening in Europe at the time, similar to Richard Adam’s Watership Down. Based on Adam's battle experiences in 1944 Holland, Watership Down is about another easily dismissed animal, the rabbit.
The Bambi books are written in a simple but not childish style. The animal characters are anthropomorphized, but the descriptions of the forest and the facts of their lives are realistic. The Disney animated version of Bambi was released in 1942 -- it has moments of lyrical beauty. The movie’s artists took great care to accurately portray deer anatomy and behavior.
The original Bambi was a Western Roe deer (Capreolus capreolus), native to Europe, about half the size of our white-tailed deer (Odocoileus virginianus virginianus) native to southern Canada and most of the U.S. However, these two species share many characteristics.
A male white-tailed deer on average weighs about 135 pounds, females 120. White-tails have a reddish coat in summer, a gray-brown coat in the winter. White-tails communicate in many different ways, including sight, sound and scent. They snort or raise their tails to signal danger to other deer in the vicinity. Deer can make a range of sounds that are unique to each individual, including bleating, squealing, snorting and grunting.
Deer prefer habitat where wooded areas intersect with open areas. They feed in both areas, and can use the forest for cover. The open areas may be croplands, pasture or landscaped yards. When portions of forested areas are cleared for residential development and roads, or conversely, when croplands are transformed into residential areas with trees and landscaping, habitat for deer is created. It is thought that roe deer proliferated during the Neolithic period when agriculture began clearing forest in Europe..
Capable of leaping over a barrier up to 12 feet in height, white-tails are heedless of most fences. As many a rural home owner learns to her frustration, white-tails feed on a wide range of plants. Attracted to woody shoots and stems (such as freshly planted ornamental shrubs or tree seedlings), deer also eat nuts, acorns, berries, mushrooms, leaves and grasses. Their favorite cultivated crops are soybeans and corn.
Perhaps we should thank them for grazing on invasive plants like honeysuckle, poison ivy, and green briar. As ruminants, deer can eat these highly fibrous foods due to a digestive system with a four chambered stomach. Partially digested food is returned to the mouth so they can “chew their cud” which is then swallowed again to complete the process. Cows, bison, big horn sheep, goats, llamas, camels and giraffes are also ruminants.
Hunters prize the bucks’ multi-pronged antlers as trophies of their prowess (the deers’ or the hunters?). These are termed antlers because they are lost and replaced each year unlike horns which grow continuously on animals like sheep and goats. Antlers on does are extremely rare but do occur.
One can often find shed antlers lying in the woods. Antlers begin sprouting on the male deers’ heads in late March and early April. Skin and blood vessels cover the bone of the antlers as they grow. This covering is known as “velvet.” In late summer, the males’ testosterone levels rise, the bone of the antlers hardens and the velvet dries and falls off. Deer scrape and scratch their antlers against trees and other objects to help shed the velvet. The color of antlers ranges from white to brown. Biologists don’t seem to be certain about why—perhaps heredity.
In October, the shortening length of the daylight hours triggers the breeding season. Male white-tailed deer use their antlers to establish dominance and fight for breeding rights with the does. By November most does are pregnant. In January, the bucks' testosterone levels drop and the antlers fall off. The males who are in the best physical condition lose their antlers last. Gestation ends in May or June when the fawns are born. Most fawns are single births, but does in good condition often have twins.
A white-tailed deer's home territory is usually less than one square mile. Family groups consist of a mother deer and her fawns. When a doe has no fawns, she is usually solitary. Bucks may live in groups of three or four, but are mostly solitary in mating season. The large groups I saw on my drive appeared to consist of several adult females with their half-grown offspring.
Newborn fawns lie still in a carefully chosen spot and are visited several times a day by the mother, to allow nursing and grooming of the infant. After a few weeks, the fawn is led by its mother to explore the world beyond and sample vegetative foods. A fawn is supposedly capable of living independently of its mother at only two months of age. But the young deer I saw were enjoying a lengthy association with their family group.
Many facts about deer taken from an article by Brian Eyler, Deer Project Leader, for Maryland DNR.
Thursday, January 21, 2010
The reservoir bed is being restored to forest. My friend Bill, my forestry consultant, conjectures that the new trees in this photo (in the white protective sleeves) include water loving species like sycamore near the stream, and also varieties of eastern hardwoods like walnut and oak. I'm finding that when I search for information about my local watershed, it is often the fisherfolk, especially the fly fishing aficionados, who are most in the know, at least of those who aren't biologists, surveyors and designated water quality keepers. The fisherfolk are the ones on intimate terms with the creeks and streams, and the fish therein. If a creek runs through it, they are interested. Which makes me more interested in them and what they do. I just might have to finally look into fly fishing...
Friday, January 8, 2010
The first category of links is Watersheds. I click on the link to the Environmental Protection Administration website, punch in my zip code and a map of my Watershed comes up. I knew I live in the Chesapeake Bay watershed and the Potomac River Valley, but more specifically I find that I live in the watershed designated as Conococheague-Opequon, by the United States Geological Survey, aka Cataloging Unit 02070004. Conococheague and Opequon are nearby creeks that drain into the Potomac. Sound like Native American words, as is Potomac. (A tangent to research but let’s keep focused here!)
There are links to various other sites. I can peruse multiple water quality studies and link to a range of water quality advocacy groups for my watershed. I try to read over one water quality study and rapidly begin drowning in technical terms. I’ll need to get help from a new friend who is a fish disease expert.
I learn that I live in what is known as the Upper Potomac River Basin (within the political state of Maryland,that is). A fact sheet on the total miles of wadeable streams in this area shows that the Fish Index of Biotic Integrity (FIBI), which is based on fish populations, is 55% poor, 31% fair and only 14 % good.
That does not sound encouraging.
Do you know the FIBI for your area? FIBI sounds like a particular concern for fly fishermen--indeed a group called Antietam Fly Anglers are the ones who posted the fact sheet. http://www.dnr.state.md.us/streams/pubs/upperpotomac.pdf
This is when features of the female sex organs are found in the sex organs of male fish, and vice versa. It is believed caused by pollution in the water (endocrine disruptors).
The EPA site is mind-boggling. There is an Envirofacts page http://www.epa.gov/enviro/
where you can easily find air quality, radiation, toxic waste emitters, compliance reports, etc all according to your zip code! I did not realize how easily available all this information is online. It is not something that is talked about everyday on your local news, in your local paper, or among your co-workers ‘around the water cooler.’ But it should be. Why isn’t it?
Well, just one hour of discovery and I have a multitude of more questions. Perhaps that is the point, once you begin knowing your ecological address you become engaged with the reality of the world in which you are living on a different level.