NATCHEZ NATURALIST
NEWSLETTER:
from the woods near Natchez, Mississippi, USA

July 6, 2003

GRAZING RABBIT AT DUSK
Dusk usually finds me sitting in my rocking chair reading in the office/barn's breezeway, binoculars ready beside me. That position affords a wonderful view toward the west across the Loblolly-sapling field, to the tree line along Sandy Creek, and beyond. You can see a fine picture of me in the breezeway, taken by my neighbor Karen Wise, at www.backyardnature.net/j/jimsdoor.jpg

Often when I'm sitting there a certain young Eastern Cottontail, SYLVILAGUS FLORIDANUS, forages in the grass about 30 feet away. When he appears I put down the book, bring up the binoculars, and watch. I'm always impressed by two observations.

First, a rabbit's head and neck are strikingly similar to those of a deer, just much smaller and with the snout shorter. They're the same color, have similar short, thick fur, and both have wide cheeks, big black eyes and noses, and tall, slender, ever-twitching ears. Of course such similarities might be expected because both rabbit and deer reside near the bottom of the food pyramid where both spend a lot of time nibbling herbage.

The nibbling is the second interesting point. The rabbit I watch snips off a grass stem, then that entire stem disappears into the rabbit's mouth, and it's the same with the next grass stem, then the next and the next. One just wonders how a little rabbit can consume and digest such a large mass of coarse, tough roughage. Naturally, this wonder sent me Googling the keywords "rabbit digestion."

From my own hunting days as a kid on the Kentucky farm I remember that rabbits contain more than their share of guts. To be precise, a Googled-up site informed me that a rabbit's digestive system accounts for almost 20% of it's weight. The fact I hadn't known earlier was that this impressive gut produces two distinct types of feces.

When a rabbit eats, its food goes down the esophagus into the stomach, which does little more than sterilize the food and forward it into the small intestine. While in the small intestine up to 90% of the protein, starches and sugar are absorbed. After these nutrients are removed, the small intestine sorts what's left. Undigested fibrous material is passed into the colon, where it is formed into the hard, round pellets we often find in our gardens, for, once the pellets are formed, they are defecated.

However, that's not the whole story. The small intestine's softer, moister food, instead of being sent into the colon like the hard, round pellets, is shunted into a special pouch known as the caecum (SEE- kum). Here anaerobic bacteria ferment the material, making vitamins and proteins available. Part of this is absorbed into the rabbit's body, but some is left, and what is left is then formed into a second kind of pellet. These pellets are soft and moist, and known as caecotrophs. The caecotrophs are then emptied from the caecum, pass through the colon, and are finally voided.

Therefore, rabbits excrete two kinds of pellets, one being hard, dry and spherical (the ones we find in our gardens), and the others, the caecotrophs, being soft, moist and clustered together like grapes.

We seldom see caecotrophs, however, because they are typically expelled at night and, more to the point, the rabbit quickly eats them, typically taking them directly from its anus. Of course this is done to recycle the nutrients, to assure that none are wasted. You can read more about this and see a nice diagram of the rabbit digestive tract at www.nixonandmarshall.co.uk/rabbitdigestiontract.html

*****

BEES COLLECTING GRASS POLLEN
The grass in which my evening cottontail hops is Carpetgrass, genus AXONOPUS. It's a tough species with thick, wiry stolens, a species mostly restricted to the Deep South, and which in our area often takes over marginal land that's occasionally bush-hogged. Carpetgrass blades look like any lawn grass, but its flowering shoots, or inflorescences, grow nearly knee high and consist of two slender flower spikes arranged in a shallow V atop a slender stem. If you're trying to keep your lawn "neat" and you have Carpetgrass, these flowering spikes will drive you nuts, for they emerge soon after any mowing, and are pretty conspicuous.

Certain bees love this grass. Nowadays you see them collecting pollen from the purplish-black anthers dangling from the inflorescence's flowers on slender white filaments. The bee lands at the bottom of the inflorescence's V, takes two to five seconds to climb up a spike, then flies to the next grass to repeat the operation. This is done again and again. During these climbs pollen catches in hairs on the bees' legs. The bees then pack the pollen into little pollen baskets on their legs. You can see a picture of a bee with full pollen baskets on its back legs at www.durhamsbeefarm.com/images/honey_bee_with_pollen.jpg

If bees can collect nectar, why should they bother with dusty, messy pollen? The main answer is that nectar, just like Coke and Pepsi, contains plenty of calories, but not enough protein, vitamins and other nutrients to keep a body alive. Using special glands in their heads, bees convert pollen into a highly nutritional "brood food" for their young.

In fact, the sale of bee-collected pollen has become a real industry among humans, too. The hype at one Web site selling "bee pollen" tells us that bee pollen contains "All 22 elements of the human system. All essential amino acids and is a complete protein. Vitamins A, B Complex series C, D, E, K and Rutin. 28 Minerals, Trace Mineral needed for good health. Enzymes and Co-Enzymes necessary for good digestion. No cholesterol. Only 90 calories per ounce... "

Happily, bees are not killed in order to rob them of their pollen bags. When bees from which pollen is to be collected enter their hives they crawl through a series of 1/4-inch wiring. During this maneuver pollen is scrapped harmlessly from their legs, then drops into a tray for collection.

You can receive a free sample of bee pollen by filling in the form at www.pollenpower.com/

*****

TOBACCO HORNWORM
I only have four tomato plants in my new garden, so when one morning I saw that some leaves on one of the plants had disappeared, I knew I had trouble. Searching my plant I found what I expected: a glossy, green, finger-sized hornworm.

I'd been thinking of suckering my tomatoes, so each day I began placing my hornworm on a sucker I was glad to be rid of, and each night he'd eat two or three sucker leaves. After about four days the caterpillar was over 3 inches long (75 mm) and he was eating more every day. Just as I was running out of suckers, suddenly one night he disappeared. Either a critter ate him, or else he crawled off to metamorphose.

Naturally I assumed that this was a Tomato Hornworm. However, I wanted to scan him for my nature-study site, and during my research for writing about him I came to realize that really he was a Tobacco Hornworm, MANDUCA SEXTA. It turns out that these two hornworm species are very similar in appearance and both eat tomato plants (both tobacco and tomato plants are in the Black Nightshade Family, the Solanaceae). However, the Tomato Hornworm has a black "horn," while the Tobacco Hornworm bears a red one. You can see on the scanned image that my tomato-eater had a red horn. He's at www.backyardnature.net/pix/t-hrnwrm.jpg

*****

THE BIRDS OF INDEPENDENCE DAY
On Friday, July 4th, I made my first serious bird walk at this new location, beginning around 8 AM. At first it didn't seem like a good birding day at all. Thursday afternoon we'd received over an inch of rain so that morning everything was soggy. It was overcast and foggy, rather somber, with more crickets calling than birds. As I started off it was a muggy 78° (26C) but by 10 AM it was 87° (31C) with sunlight breaking between gorgeous white thunderheads building all around, and already it was thundering in preparation for the afternoon storm. Here are the birds found, listed in the order seen, to help you imagine the flow of music accompanying my passage:

The two greatest surprises about the birds here are that Painted Buntings are so common, and that Blue Grosbeaks, while not common, aren't uncommon. Both of these are seed-eaters, so they are at home here because for several years the fields here have been growing up, "going to seed."

I think that sometimes Blue Grosbeaks are misidentified as Indigo Buntings or maybe even as Eastern Bluebirds. Bluebirds have rusty-red breasts while the males of the other two species are nearly entirely blue. However, Blue Grosbeaks are much larger than Indigo Buntings, have more massive beaks and a sort of black eye-mask, and the wings of Blue Grosbeaks bear conspicuous brown bars while the wings of mature Indigo Buntings seldom show much brown at all. You might want to compare a picture of the Indigo Bunting at www.naturesound.com/birds/hires/bntng.jpg with that of a Blue Grosbeak presented at www.imperial.cc.ca.us/birds/bluegros.jpg

Friday's list will serve as my "baseline list" for the birds here. These are species so perfectly adapted to this land and climate that they choose to raise their families here. Neither transient migrants appear on the list nor "snow birds" -- species who come here just to escape the cold winters farther north. In a sense, the fundamental nature of this landscape has been encoded in these birds' genes. If this spot of land has a voice, then it is surely the singing of the birds on this list.

*****

ATOP THE ECOLOGICAL PYRAMID
Earlier I alluded to the fact that rabbits and deer occupy a low position on the ecological pyramid.

There are many ecological pyramids and they are fun to think about. Back in college ecology class we studied the ecological pyramid for a field of bluegrass. In one study it took 5,842,424 "producers" (plants capturing sunlight energy) to support 708,624 plant- eating invertebrates such as snails and millipedes, who in turn supported 354,904 predatory invertebrates like spiders and predaceous beetles, who themselves constituted the food supply of 3 vertebrates at the top of the pyramid, mainly birds and moles.

Another study showed that it took 20,000,000 alfalfa plants weighing 17,850 pounds to fuel 4.5 calves weighing 2,250 pounds, to maintain one human boy weighing 105 pounds.

These data are worth reflecting on. Seldom do we see so starkly the fact that Life on Earth is structured in such a way that, generally, many must contribute to the welfare of a few "higher up."

A thought that occurred to me this week was that we at the top of all the main ecological pyramids -- we who can sit in our comfortable rocking chairs at dusk and gaze at hungry, nervous cottontails while our own bellies are satisfied with the evening's bowl of oatmeal and blackberries -- we become something like ecosystems ourselves.

But instead of being composed of species as are biological ecosystems, we are packages of ideas. Instead of needing to maintain a proper equilibrium among primary producers, herbivores and carnivores, we must struggle to maintain equilibrium in our emotional, intellectual and spiritual realms. Instead of evolving toward ever more complex biological organisms and communities of organisms, it is our destiny to evolve toward ever more sophisticated insights and patterns of feeling and behavior.

Moreover, as the ultimate state of the evolving ecosystem appears to be that condition in which energy is transferred most efficiently among interdependent organisms and communities, I would guess that the final desired state of us at the top of the Earthly Pyramid of Life is this: To evolve toward gracing our every moment of life with feelings of awe for the beauty of the Universe, love for all things around us, and reverence for the Creator of all these things.

For, awe, love and reverence are the most concentrated forms of human feeling I know, so expressing them must be the most efficient manner of "being human."