Some folks find snakes fascinating and beautiful. In others, snakes inspire an especially large measure of fear and loathing. Harvard biologist E.O. Wilson addresses this response in his essay, “The Serpent,” from Biophilia (Harvard University Press, 1984):
“What is there in snakes anyway that makes them so repellent and fascinating? The answer in retrospect is deceptively simple: their ability to remain hidden, the power in their sinuous limbless bodies, and the threat from venom injected hypodermically through sharp hollow teeth. It pays in elementary survival to be interested in snakes and to respond emotionally to their generalized image, to go beyond ordinary caution and fear. The rule built into the brain in the form of a learning bias is: become alert quickly to any object with the serpentine gestalt. Overlearn this particular response in order to keep safe.”

I have no intent to press those with established opinions about snakes. As Wilson points out, humans have “an innate propensity to learn such fear quickly and easily past the age of five.” But admittedly, it’s pleasing when kids respond with open interest to animals—especially maligned species that are actually beneficial. Last year my son and I were walking in the meadow and came upon this same den of emerging garter snakes. He’d never seen anything like it. Rather than recoiling, he stopped to watch for a long time, plying me with questions. I explained that it’s always wise to give wild animals space, but that these small snakes are generally harmless and helpful to humans—among other things, they eat worms, leeches, slugs, and a variety of insects. They congregate together underground during the winter, hibernating in groups for warmth. To the unfamiliar observer, the snakes may look like a living ball of twine, rolling and swirling as they emerge from the entrance of a hibernation den. This behavior, delightfully creepy to watch, is evidence of the other practical purpose behind garter snakes' communal hibernation: males and females have immediate access to each other in spring. After mating, each snake retreats to a separate domain around the area. Summer is not a time for sociability. This is not the last we see of them, however. Later in the season we will inevitably encounter slender hatchlings, which appear suddenly underfoot in the yard like animated blades of grass or take their turn to sun on the deck. Watch out garden pests—here they come!

Earlier this week we had a couple of warm days and a lot of melting. The sound—a steady drip and slap—overwhelmed even the enthusiastic songs of birds around the neighborhood. Water streamed from rooftops and soaked the trunks of trees. It flowed down driveways in sheets and converged on the street. Heading off to pick up my son after school, I walked between rivulets that slipped under piles of snow along the edges of the lane. Where winter ice had broken the asphalt, murky pools formed. But the pull of gravity was clear. Meltwater escaped through every crack, rejoining the flow and slipping westward toward the catch basin at the lowest point in our neighborhood watershed.

As I stood waiting for the bus, I unfocused my camera and took a picture of a spot where where tiny ripples swirled over the rough asphalt. The result is a patchwork of reflected light. I like the picture, but it leads me to something bigger. Water is in connection with the land as well as the light. What does that mean? Anything that lies on the street—leaves, dust, road salt, fertilizer, pest waste, and more—becomes part of the flow. Consequently, how we treat the land (and the air) affects the quality and quantity of water. It's a simple equation, but one we often forget.

Today is World Water Day. The United Nations cites increasing urbanization—the growth of population in cities—as a major influence on water resources globally. You'll use water many times today. When you do, stop to ponder this life-giving resource. Below are a few of the many available resources to help you learn how to protect it.

World Water Day from the UN
CDC announcement (with background and data)
Nine Mile Creek Watershed District
summary of the Clean Water Act
Renewing Earth's Waters, by Christine Petersen

A bird's sail-shaped nictating membrane is firmly affixed by ligaments at two points (the top of the eye and the side closest to the bill). The third attachment is movable, allowing it to sweep sideways over the cornea in a motion something like that of a windshield wiper. As I observed, in a quiet moment the bird may flick the nictating membrane open and shut a few times as a sort of preening action. The membrane is also closed when the bird needs protection from environmental hazards.

This structure shows a lot of adaptive variation. Raptors have a nearly transparent nictating membrane, allowing them to see while flying but also protecting the eye from injury caused by twigs, branches, or struggling prey. Imagine the benefits of such protection for fast-flying or pelagic (sea-faring) birds, which otherwise face the drying effects of wind and abrasion from small airborne particles. Woodpeckers and nuthatches have unusually thickened, opaque nictating membranes that protect their eyes from flying wood chips.

Like raptors, diving birds have a transparent nictating membrane. I'm very nearsighted and always appreciate the little bit of visual enhancement provided by goggles when I swim. I wondered if nictating membranes similarly improve the vision of birds swimming under water. Researchers looking at this question found that the membrane lies very close to the eye and has a curvature almost identical to that of the cornea (i.e., it is not faceted like my goggles). As a result, there is no significant refraction of light and no noticeable improvement to a bird's vision.

Nictating membranes are common in every vertebrate group except mammals, suggesting that the structure evolved in fishes and was lost much later by some mammals. Monotremes (the platypus and echidna, most "primitive" among the living mammals) have nictating membranes, as do marsupials. A few groups of placental mammals retain them, in particular those that are aquatic—seals and sea lions, manatees and dugongs, and beavers. For polar bears, nictating membranes serve the additional role of protecting against UV light that is so strong in the polar environment.

A tiny member of the loris family, found in West Africa, is the only primate with fully functional nictating membranes: able to clean the eye and move freely across it. But this structure has not been completely lost in other primates. Take a look in the mirror. See the pink, crescent-shaped blob at the inner corner of your eye? That is a nictating membrane—or what's left of it. Opthalmologists call this the plica semilunaris. It's often said to be vestigial, a scientific term for structures that have been retained through evolutionary time but lost their function. That's not an entirely accurate description in this case. Although the plica semilunaris has no ligamenture that permits movement, it still helps to clean the eye by producing fatty secretions to which pollen, dust, and other particles stick. These waste materials glom up and weep out. Nictare—blink, blink—and your eyes are cleaner. No goggles required.

At the dramatic conclusion of the season's first thunderstorm, the base of a passing cloud takes on mountainous topography. Meteorologists use the term mammatus to describe these distinctive formations. Warm, moist air in the thundercloud rises in a typical convective updraft. It strikes a layer of cooler, dry air in the atmosphere above and spreads outward to produce an anvil-shaped cloud. Ice crystals fall to the bottom of the cloud where they sublimate, changing state directly from ice to water vapor. As this cool air sinks in pockets across the base of the cloud, localized, reverse convection currents are set up—the puffballs that give mammatus clouds their texture.

he proudly informed me that birds only migrate if they can’t find their usual foods (such as insects). We enjoyed learning to recognize some of the species that frequent our yard in winter: black-capped chickadee, bluejay, American goldfinch, dark-eyed junco, American crow, Northern cardinal, white-breasted nuthatch, and several woodpecker species make up a partial list. (This year we have even been seeing American robins, historically the indicator of returning spring.) Each morning, as I watch the sunrise from the kitchen, I notice the smaller birds flitting to our feeders and heated birdbath from hidden perches among the trees and shrubs. In the depths of winter their business is conducted in almost unnatural silence. Later in the morning, if the day is warm enough, the birds’ voices begin to reach me through the windows of my office—impatient squawks of bluejays; burbling chatter from chickadees; stern-sounding ticks made by foraging juncos. The sound comes in waves throughout the day as winter flocks of each species move through their territories in search of food. As evening falls I resign myself to another long stretch of silence, and I look forward to the cheery, tri-toned wake-up call of my whip-poor-will alarm.

This morning, through the cottony strands of sleep still tying my mind to the dreamscape, I realized that something was different with my “alarm.”  I woke to a sound far more resonant and insistent. A sidelong glance at the clock—6:10 a.m.—told me that this sound had not come from my alarm, which was not due to go off for another fifteen minutes. The sound came again. Who-ha-hoo-o-o! And within a few heartbeats, the great-horned owl’s sonorous call was repeated. I smiled and pulled the blankets closer around me as I listened to the long concert.

Great-horned owls are the first of our winter-resident birds to nest, and hooting becomes most intense just before the female lays eggs. Devoted mates, the owls form pair-bonds that endure for years. Rather than migrating, the pair establishes and maintains a permanent territory. (Localized winter food shortages may break this pattern, prompting temporary southerly movements, or irruptions, toward better food sources.) Territorial boundaries are reaffirmed each autumn—just in case any young upstarts have showed up in search of a home. The big birds become unusually visible at this time, often perching on exposed branches or hunting in the afternoon. Great-horned owls also become more vocal in autumn. One of my most vivid memories from my son’s infancy is of sitting in his room during feedings in the middle of the night. As we rocked together in the chair by the window, the sleepy silence was often broken by the calls of a great-horned owl. Before putting the baby back in his crib I frequently stood at the window, swaying gently as I searched for the owl’s dark silhouette. The bird’s preferred hooting spot was the highest bare branch in the neighbor’s yard, from which his voice carried far across the trees and lake. Though years have passed, the sound of owl-song still evokes those nights with my newborn son.

It’s hard to say exactly where the owls’ nest is located. Great-horned owls don’t construct nests as some raptors do, but take over the nests previously occupied by crows, other raptors, or even squirrels. These might be stick nests, somewhat exposed in a winter-bare deciduous tree, or hollows in an aged tree. Around our property are many choices. I’ll be keeping a close eye on several old maple and oak trees at the bottom of the meadow. Each autumn we’ve seen great-horned owls perched on their branches or on the ground nearby. And one morning this past January, after a storm, my son and I were thrilled to notice a large set of wingprints in the meadow’s fresh snow—evidence of the bird’s attempt to capture prey on the ground.

Whatever the location of the nest, several tiny owlets will hatch in mid-March. By early May, as frogs begin to call along the lakeshore and the trees in our orchard reach full bloom, the fledgling owls will be ready to fly beside their parents and begin their education in the ways of the owl.

If the female has already begun to lay her eggs, this morning’s round of owl-song may be the only concert we get. But soon enough the mornings will ring with the din of eager songbirds. For now, my whip-poor-will alarm provides sufficient daily affirmation of one of the first realizations I made when becoming a naturalist: Listen for birdsong every day, just because you can.

I'm standing on the coastal trail just west of San Francisco's Golden Gate. Fog obscures most of the famed structure, though now and then a blazing patch of red is revealed as a gust of wind pushes aside a corner of the low-lying cloud. If I were asked to choose a mascot to represent this grandiose landscape, the brown pelican would have no rivals. To the inexperienced observer this might seem an odd choice. Weighing up to eight pounds, with a wingspan greater than 7 feet and a curving neck that culminates in an improbably long, hooked bill, brown pelicans look like make-believe creatures from a child's storybook: gangly, disproportionate, and comical. Yet airborne pelicans are the epitome of grace—flapping with slow ease; making fast, steep plunges in pursuit of fish; flying in long, curving formations that follow the breaking lines of waves.

In the 1820s and '30s, while traveling across the nation to study and paint avifauna, John James Audubon had many opportunities to observe brown pelicans. He found them to be "one of the most interesting of our American birds," and had this to say about pelicans on the wing.

"The flight of the Brown Pelican, though to appearance heavy, is remarkably well sustained, that bird being able not only to remain many hours at a time on wing, but also to mount to a great height in the air to perform its beautiful evolutions. Their ordinary manner of proceeding, either when single or in flocks, is by easy flappings and sailings alternating at distances of from twenty to thirty yards, when they glide along with great speed. They move in an undulated line, passing at one time high, at another low, over the water or land, for they do not deviate from their course on coming upon a key or a point of land. When the waves run high, you may see them "troughing," as the sailors say, or directing their course along the hollows. While on wing they draw in their head between their shoulders, stretch out their broad webbed feet to their whole extent, and proceed in perfect silence."

Autumn weather is as changeable as a teenager's moods. On Sunday night a heavy bank of clouds rolled in just as the Harvest Moon began to peek over the eastern horizon. The low pressure system parked over our heads and remained in place for two days, bringing two inches of much-needed rain.

Wednesday dawned fresh and golden. By early afternoon warmer air had caused unusual cloud formations to build up. Altoculumulus undulatus clouds are named for their resemblance to rippling wave trains along

the surface of the water. Also known as billows, these clouds form as the result of wind shear. Localized differences in wind speed and direction break up larger altocumulus clouds, reshaping them as narrow cloud-rolls. Billows may be ramrod-straight or form gentle curves, but are always evenly spaced in parallel rows.

I recall seeing billow clouds a few times in my childhood. Back then I found their symmetrical design a little frightening, reminiscent of the ribs of some skeletal sky-giant. As an adult I observe natural phenomena through the rational lens of science. Yet plenty of youthful imagination still tinges my view. Standing in the yard my eye was drawn to the straight line of those clouds, and for a moment I imagined having the ability to fly along that sky-path. But even as I watched, the clouds began to lose their structure—joining then stretching, thinning and breaking apart. Within 20 minutes, the sky was completely clear and blue. And I remained affixed to the ground.

Tentative sunlight at the terminus of the week brought local maple trees to the peak of color. While our neighbors began to spend evening hours raking, trees in our meadow and yard have steadfastly held on to their leaves. A golden glow fills the air at all hours, seeping through the windows and reaching my office as I work. As if I needed another distraction!

But this too shall pass. As I write this in the late hours of Friday night, the drying leaves of a pin oak outside my office window begin to rattle. The wind has picked up from the west. With it, capricious Autumn may bring the first snow of the season.

Announced by all the trumpets of the sky,
Arrives the snow
—Ralph Waldo Emerson, from "The Snowstorm"