November 2005

You are browsing the site archives for November 2005.

1. Tell me what language your left hand speaks while your right hand is busy here with the pen. Parse a sentence in it.

2. From dreaming about salamanders, can you remember how it felt to breathe through your skin & listen with the bones in your feet? Use both sides of the paper if necessary.

3. You wake to a thunderstorm on a hot August night; fear mingles with pleasure at the cooling breeze. If you were God, would you prefer being dead to a state of disembodied abstraction? Please provide etymologies for any neologisms.

4. A few snowflakes are sifting down from a clear dawn sky. It’s quiet. In another couple of minutes, the black lace will turn into ordinary treetops. If you wanted to stop time, how would you go about it? Show, don’t tell.

5. I’m curious about what you might have muttered before flushing down that mouse you found floating dead in the toilet just now. Please explain why I have no right to know.

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The house made of sunset, day before yesterday.

I’m traveling to Mississippi to visit my brother and his family; I won’t be back until around December 1. While I’m gone, please consider visiting some of the blogs listed in the column to your right.

I think I just witnessed a gang war between crows. It was a little before ten in the morning, on a day with intermittent flurries. At first I thought the crows were mobbing a predator – that’s what it sounded like – but then I realized they were diving at each other in the sky over Sapsucker Ridge to the west. More birds kept streaming overhead from the east all the while I stood watching, about ten minutes. Most of them landed in the treetops and added their voices to the raucous cheering section for the aerial battles, which included at least a couple dozen combats at a time; the ridge blocked my view of a lot of the action. Brisk winds aloft made for an exciting display of maneuvers: diving, chasing, feinting – Top Gun stuff, for sure.

As is usual with crows, it’s difficult to know how to interpret what I was watching. Maybe it was all just play behavior, occasioned by the wind conditions. Ten minutes later, when I stick my head out the door, there’s no sign of a crow anywhere.

Most non-specialists would probably tend to assume that scientists know a lot about the behavior and life histories of the commoner birds and mammals, especially here in the northeastern U.S., but such is rarely the case. A recent study of white-tailed deer, for example, made a couple surprising discoveries simply by fastening digital cameras to bucks’ antlers: deer touch muzzles constantly, they found. And one deer kept returning to the same spot to drink, despite the availability of closer water sources. What’s surprising about this is that white-tailed deer are probably one of the most-studied animals in the world, apart from human beings, laboratory rats, and fruit flies. How could previous researchers have failed to notice such apparently common behaviors?

So I wasn’t sanguine about throwing much light on what I’d just seen by a quick glance through the literature on the American crow (Corvus brachyrhynchos). The Stokes Guide to Bird Behavior, Volume 1, confirms that “There has been amazingly little study of Crows by researchers, so most of the best questions about the birds still cannot be answered.” Its summary of research to date (1979) included this:

Outside of the few months of the breeding season, Crows are extremely gregarious. After the last young have fledged, the family group usually joins other groups of Crows, and these begin to form a large flock that divides up for feeding during the day, but gathers again each night to roost. The roost becomes an important focal point in the birds’ life outside the breeding season. Each morning the roost breaks up into smaller flocks that disperse across the countryside to feed. Some flocks may fly up to fifty miles from the roost each day. In midafternoon these smaller flocks start back toward the communal roost. They fly along flight lines used each day and are joined by other flocks as they go. Often there are preroosting sites, where flight lines coincide and Crows stop to feed before making the final trip to the roost. At these spots there may be much chasing and other spectacular dives as the returning Crows join the others at the preroosting spot. Then just before dusk all the Crows in the area enter the roost site together.

What I saw would seem to have occurred at the wrong time of day for preroosting behavior. But this description does make it clear that not all chasing and diving is antagonistic.

In The American Crow and the Common Raven, Lawrence Kilham describes territorial antagonism across a boundary between two large groups of crows in Lyme, New Hampshire.

I watched forty-five territorial encounters beween 1981 and 1983. While no two were alike, certain behaviors were observed repeatedly. Cawing, heard in thirty-eight of the territorial encounters consisted of sharp caws corresponding to what Good (1957) refers to as warning calls and Camberlain and Cornwell (1971) as simple scolding calls. The crows of both groups cawed when flying toward each other at a distance. This was especially so on early mornings when most encounters took place. If one group alighted in the fields and another in trees, the latter did the most cawing….Other forms of behavior [aside from walking and bluffing displays] included aerial melees (n = 17), bunching (n = 5), and pursuits (n = 5). The melees were spectacular when all members of both groups swirled into the air for three or four seconds, with some swooping on others….

Territorial behaviors also included circular flights (n = 11), which carried the crows of one group a short distance over the boundary into their neighbors’ territory as if to demonstrate where the boundary lay, and treetop sitting (n = 17). The latter was particularly striking on November 26 [1983] when the crows of both groups, after a series of melees, perched on the very tops of their dead elms in full view of each other.

Kilham found that groups facing off over common boundaries tended to be “of the same or about the same size.” None of the conflicts he observed seem to have resulted in serious injury, let alone death. And he speculates that most of the actual combats are left to the dominant or nuclear males, based on his observations of American crows in Florida, and on another scientist’s observations of white-winged choughs, which have similar social patterns.

A more recent source of information is the American Crow monograph for the authoritative Birds of North America series: No. 647, by N. A. M. Verbeek and C. Caffrey, 2002. Over twenty years after Stokes, not much has changed: “Although much has been published about this [species of] crow, we still know relatively little about it.” They add that observations made in one locale may not describe the behavior of crows from somewhere else in the species’ range.

One of the things that appears to vary from place to place is whether territories are maintained throughout the year. Crows on Cape Cod and in New Jersey, California, Oklahoma, Florida and New York do maintain year-round territories, but crows in Ohio and in the northern part of their range in Canada do not. So goodness knows where central Pennsylvania fits. On the topic of aerial melees, Verbeek and Caffrey simply quote Kilham. If there haven’t been many other observations in the literature, that may be because few observers are as patient as he was (me, I went inside when my hands began to freeze). Also, given that American crows favor mixed and open habitat, territorial boundaries might tend to pass through forested areas or follow wooded ridgetops, making interactions along them harder to observe.

As habitat generalists and omnivores with well-developed learning abilities and complex social structures, crows offer many parallels to the behavior of humans and other primates. To a non-scientist like me, it seems natural to characterize group antagonistic behavior as a gang war, but I have to be careful not to let my judgements be too colored by prejudices which are not merely anthropocentric, but ethnocentric as well. For example, we Westerners tend to associate wars with struggles for dominance, leading ideally to the conquest of one group by another. But among the crows that Kilham observed, territorial conflicts seemed to work more to maintain a balance of power – not unlike the low-intensity conflicts that are thought to have been the norm for warfare in much of native North America before 1492. Kilham watched wandering flocks numbering as many as forty crows trespass into group territories without much conflict beyond a lot of cawing. These flocks apparently consisted of nonbreeders – juveniles with no interest in setting up a territory of their own.

It’s also important to remember that territories are maintained cooperatively, for the shared benefit of the crows that use it: “Territories provide improved protection through greater familiarity with safe areas; reduced interference with nest building and copulations; greater protection of stored food; and increased assurance of a good food supply,” Kilham notes. Nor does cooperative behavior end when the breeding season is over. Fall and winter roost sites can only get to be as large as they are by bringing together crows from diverse, non-overlapping daytime feeding territories, and mixing local birds with migrants – foreigners from the north. I wonder if the diving and chasing behavior commonly observed at preroosting sites doesn’t represent a playful, ritualistic form of inter-group conflict? After all, even among humans, the line between play and warfare can get awfully fuzzy – think of the World Cup. In any case, whether we choose to focus on the relatively rare, spectacular outbreaks of crow-to-crow combat, or on the cooperative nature of crow sociability as a whole, probably says a lot more about us than it does about the crows.
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The most promising research on American crows since Kilham comes from Kevin McGowan of Cornell University, who has been banding crows and following their progress from year to year since 1988. His crow website includes helpful information on roosting behavior in the F.A.Q. page, and an overview of his own crow study, with links to publications. He writes, “I frequently see crows locked together tumbling out of trees in the spring. Although I have never witnessed an actual killing, I would not be at all surprised to see crows kill another crow from outside the family group that was trespassing.”

Bored New Yorker – Sedementary rock seeks metamorphosis. Extremes of heat and/or pressure only. No smokers.
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GREETINGS FROM TURKMENISTAN – JHRWTCM I.S.O. GRTYF for NBATR and PUIIN. Friendship first. No smokers.
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Free to Good Home – Lickin’ stick. Needs coat of varnish. No smokers.
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Ready to have fun – Flesh-eating zombie, 41, 5’10”, brown/blue, 120 lbs. I.S.O. pretty much anyone. No smokers.
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Real Men Only Need Apply – SBF, 39, recovering Catholic. In search of Happy Meal. No transubstantiation, smokers.
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Lost – Disgruntled postal worker. Answers to name of Merle. Real friendly, except to smokers.
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STILL LOOKING 4 U – Prosecutor seeks violators. Murder, mayhem preferred. No smokers.
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Hopeless romantic – Big Brother: I love you. – Winston P.S.: Thank You For Not Smoking.
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Ready for new life – Failed suicide I.S.O. meaning, comfort in a cheerless world. I will turn your body into a life raft and hold on with a desperate but ultimately futile grip. No smokers.
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SWM For Ladies or Couples – Single guy, looking for no strings adult fun. Into bondage, discipline. No smokers, please.
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Mature blonde lady – High-level Washington administrator with energy to spare. Hobbies: camping, 4-wheeling, oil exploration in Arctic. Seeks teddy bear for ESA de-listing. No smokers.
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Frustrated – Where’s my duct tape? WHERE’S THE GODDAMNED W-D40? I can’t believe this shit!!! No smokers.

I’m reading Paul Zweig. This is the fifteenth poem in the third (“Eternity’s Woods”) section of his Selected and Last Poems, followed by my response. See here for details on this experiment in responsive reading. I’ll remove Zweig’s poems after a week or so to prevent egregious copyright infringement.

Bless the Earth, Bless the Fire
by Paul Zweig

Here is the wanderer with
His unwrapped soul, his parcels of pure voice …

* * * *

Hourglass

I sit as stolidly as a column of cold ash,
longing for a bell’s clapper, or the skin
of a drum that shivers under the blows
of a pair of brushes. I have held
this shape too long, I tell myself.
The fine teeth of my thoughts
are through with falling.

Across the lawn, the French lilac
still glows green against the gray trees
as if summer could last forever –
as if a craze of twigs were some disgrace,
& not the soul’s own map –
& I feel a sigh coming toward me
from the edge of the world.

Grain by grain,
the shadows are losing their firm outlines.
The sun buries itself in a white sand sky.

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The first frost came on Friday night as we sat around drinking. At a certain point, we had to bring the beer in from the porch to keep it from freezing. While I slept the dreamless sleep of inebriation, the air was crystallizing around every leaf and blade of grass, like frozen foam from the season’s drained cup.

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I love the way a beer with good head retention leaves a record of its passing in the white, lacy rings on the side of the glass. It’s a good argument for sipping rather than chugging. But that’s the funny thing about consumption, isn’t it? The more attached you become to the act of consuming, the less you enjoy it. To get the most out of a beer – or anything, really – you have to take it one sip at a time.

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The bark of pignut hickories forms rings, too, healing over the lines of holes drilled by yellow-bellied sapsuckers. They are slow-growing, long-lived trees, seemingly unaffected by the intensive tapping of their sap. Their nuts aren’t as sweet as those of shagbark hickories, but the squirrels still seem to catch most of them before they hit the ground.

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The red, black and scarlet oaks are the last trees on the mountain to turn color, long after the understorey black gums, sassafras, witch hazel and spicebush have shed their leaves. By holding onto their leaves so long, they risk damage from early snows or ice storms, but oaks are very good at sealing off wounds to prevent infection from spreading to the rest of the tree. And shedding leaves, it turns out, is about more than just letting go; new research suggests that trees attempt to poison the ground against competitors with the chemicals that form in their leaves as they turn color.

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Within the space of a few days last week, high winds stripped the ridges mostly bare, and now suddenly one can see for hundreds of yards through the woods. The rising sun hits my front porch an hour earlier, even as the dawn comes later. I don’t think of winter as a dark time, but a time of clearer light and more interesting shadows. While vistas are opening up, life is turning in upon itself, rediscovering the rewards of contemplation and of altered states.

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Who can blame shamans for trying to become bears, those champion sleepers and masters of retention? Right now, they’re living quite literally off the fat of the land, but when a bear enters hibernation, its large intestine forms what is called a fecal plug. Winter, in other words, is the one time of the year when a bear does not shit in the woods. You can walk along enjoying the dawn or sunset sky without a thought for where you put your feet.

I finally got around to reading the September issue of Natural History – possibly my favorite magazine – which features a marvelous article on how ants disperse seeds: “Jaws of Life,” by Robert R. Dunn. I knew this was an important topic for Appalachian forest ecology, because many of our spring wildflowers, such as bloodroot, Dutchman’s breeches and stinking Benjamin, depend on ants as the sole or primary agent of seed dispersal. This means, among other things, that once such wildflowers are eliminated from an area by several decades of overbrowsing by deer, or through large-scale clearcutting or other landscape alterations, they may take centuries to return on their own. As Dunn puts it, “Getting dispersed by ants… is like trying to get out of town on the local city bus. As often as not, you circle back to where you started. Seeds carried by ants are rarely taken more than a few feet from where they fall.”

So this obviously raises the question of why plants rely on ant dispersal in the first place: what advantage does it confer? Suggestions include protection from predators or from fire, or taking advantage of the rich nutrients available for the seeds’ growth in an ant nest’s midden. This last suggestion seems especially likely for the thin, acid soils of the Appalachians.

The plants go to the trouble of manufacturing a special ant lure, “a small, fatty appendage known as an elaiosome, from the Greek elaios, ‘oil,’ and soma, ‘body.’” The ants seem to find it more economical to carry the entire seed back to their nests so their larvae can eat the elaiosome, following which the seed gets chucked into their compost heap. “Elaiosomes… have evolved at least eighty-six and perhaps several hundred times around the globe…. In the Liliales (the group that includes the lilies) alone, ant dispersal may have evolved independently at least eight times.”

So it’s obvious that ants are highly valued partners for plants, even if we can’t determine the exact reasons yet. Nor is this rather extreme example of convergent evolution restricted to the plant kingdom, as a sidebar explains. This is worth quoting in full, I think. It accompanies an arresting photo of green and yellow, seed-like things with brown knobs on their ends.

The eggs of some stick insects, like the seeds of many plants, have nourishing appendages that encourage ants to pick them up and carry them away. The appendage of an insect egg is called a capitulum, and ants can remove it without damaging the egg. In the photograph above, for instance, eggs from the Central American stick-insect genus Bacteria are shown, magnified roughly fifteen diameters; the brown, knobby protuberances are the capitula.

The parallels between the elaiosomes of plant seeds and the capitula of insect eggs were first highlighted in 1992 by Mark Westoby and Lesley Hughes, both ecologists at MacQuarie University in Sydney, Australia. They gave seeds with elaiosomes and stick-insect eggs with capitula, along with several control items, to various ant species in southeastern Australia. The ants removed the seeds and eggs at a similar rate, treated them similarly, and threw them together into their garbage piles. The apparent advantage for the eggs is that, buried in the debris, they are less likely to be parasitized by wasps.

Perhaps it is appropriate that stick insects, which as adults mimic sticks, start out by living the lives of seeds.