What ecology theories are present in Aldo Leopold's A SandCounty Almanac in chapters 1-6?

Each year in late January comes a thaw. The hibernating skunkrouses and walks through the snow, leaving a track behind him. AldoLeopold, author and speaker, follows the track, wondering about theskunk's purpose and destination. There is time for such musings inJanuary.

Following the skunk track Leopold notices more signs of animalactivity as a result of the thaw. A mouse runs across the skunktrack. The thaw has exposed its network of tunnels beneath thesnow. A hawk dives from the sky for prey, \"well aware that snowmelts in order that hawks may again catch mice.\" Rabbits run morefreely, giving owls opportunities to feed.

The skunk track ends at a pile of driftwood, so Leopold goeshome again.

According to Leopold, among the benefits of owning a farm is agreater understanding of where food and heat come from. Using theexample of a felled oak used as fuel for the fire, he examines theorigin of the energy in the wood and the process that led to itsbeing used to provide warmth.

This particular oak had reached a diameter of 30 inches, made upof 80 rings. This dates the first ring to the end of the Civil War.The heat generated by burning the wood is, then, \"eighty years ofJune sun.\" And this heat is greatly appreciated by Leopold'sdog.

The oak had been struck and killed by lightning in a summerstorm. Leopold felled it, imagining that the \"saw was biting itsway, stroke by stroke, decade by decade, into the chronology of alifetime, written in concentric annual rings of good oak.\" Hethinks of the oak over the years as he saws, imagining backward intime through the Great Depression, years of changes to conservationlaws, and other significant dates in Wisconsin's conservation andforestry history. He also describes the function of the saw, wedge,and axe—tools for cutting up wood—not only as they relate just tocutting the tree but also how they interact with and reveal theyears represented by the rings.

The return of geese in March means spring has truly and fullycome. Other animals—cardinals and chipmunks—do not migrate, so theycan be mistaken about the coming of spring. But geese migrate, sothere is no room for error in timing. The return of hundreds ofgeese to the marsh on Leopold's property is a sure sign that theseason is changing. The geese show their presence and eat lastyear's corn from fields that have been hidden under snow allwinter.

Leopold notes some of the geese are \"singles—lone geese that domuch flying about and much talking.\" After careful observation heconcludes these are \"bereaved survivors of the winter's shooting,searching in vain for their kin.\" Leopold describes the noise ofthe birds in the marsh as a robust and boisterous conversationthat, by May when the geese have migrated on, becomes much quieter.Through the migration of the geese, Leopold notes, the leftovercorn from Illinois is transformed under the Arctic June sun intogoslings.

Come High Water

Because of melting snow and the farm's proximity to the river,April often brings flooding to Leopold's farm. This causes bothhumans and animals to be stranded on high areas surrounded byfields rapidly being transformed into lakes. The geese struggle tofind a place to land and feed, while the carp enjoy their largerworld. Random pieces of lumber float down the river from areasupriver. Over the years these have been collected in a lumber pilethat is \"an anthology of human strivings in upriver farms andforests.\"

Draba

The tiny white blossoms of the Draba flower can gounnoticed by those who are not looking for them. It is a humble andoverlooked flower that thrives in sand that is too poor for otherflowers. Draba is not a romantic flower, but it does its\"small job quickly and well.\"

Bur Oak

Because of its thick bark the bur oak is the only Wisconsin treethat can survive a prairie fire: \"Bur oaks were the shock troopssent by the invading forest to storm the prairie; fire is what theyhad to fight.\" Botanists can use pollen embedded in the wood oftrees to track the expansion and contraction of the Wisconsinforest over the course of this long battle between forest andprairie. Because of \"allies\"—rabbits, mice, squirrels, Junebeetles—that helped both the prairie and the forest, \"the netoutcome of the battle was a draw.\" That is, until human settlersintervened in the battle. Settlers plowed fields so that prairiefires were less common. This gave oaks an advantage as more oftheir seedlings could survive. This allowed much of the land thatwas prairie to be transformed into thick oak forest.

Sky Dance

In April and May the \"sky dance\" occurs at dusk and dawn overthe woods of the Leopold farm. \"Showtime\" changes over the weeks asthe times of sunrise and sunset change. At the appointed time themale woodcock bird appears and begins to perform a song and dancedesigned to appeal to his \"lady.\" He spirals into the sky andswoops down for an hour or more, his \"dance\" accompanied by hisunique call. Despite Leopold's careful observation of this skydance he has many unanswered questions about it, such as where thefemale is during this dance and the exact mechanism of themusic.

When dandelions begin to bloom in Wisconsin, one can listen forthe \"final proof of spring\"—the song of the upland plover, whichmigrates far to the Argentine during the winter. The plover can beseen flying overhead or alighting gracefully on fence posts. Overthe next several weeks the hens nest; the chicks hatch out and growquickly; by August the chicks have learned to fly.

The plover has adapted well to the changes human agriculture haswrought on the landscape—it lives as easily among cows and farmlandas among buffalo and prairie. They have also benefitted fromfederal migratory bird laws that protect them from hunters.

The Alder Fork—A Fishing Idyl

In this episode Leopold fishes for trout in a stream but haslittle luck. He relocates his fishing efforts to the Alder Fork—apart of the stream nearer the headwaters. While catching trout,Leopold sits on a rock and considers how much humans are like fish:\"ready, nay eager, to seize upon whatever new thing some wind ofcircumstance shakes down upon the river of time!\" He notes thatthis haste may sometimes have bad effects, but a life devoid ofthis eagerness would be very dull. Prudence may often be a virtue,but a life wholly prudent is boring. In fact, he remarks: \"Noprudent man is a fisherman.\"