A guest post by KVR Educator Cathy Chybowski
Spring is in the air!
Even if the calendar says “March,” the cold winds blow, and the snow
lingers, those of us tuned in to the changing seasons know that spring is fast
approaching. By observing and recording
natural events year after year, we can accurately predict and anticipate the
sequence in which these events occur.
The study of recurring natural events like the migration of
birds or the flowering of plants and their connection with each other as the
seasons change is called phenology.
Everyone practices phenology whether they realize it or
not—naturalists, gardeners, farmers, and homeowners, among others. “April showers bring May flowers” is pure
phenology.
What tells you that spring has arrived? Is it the first robin of the year? Like Aldo Leopold, many people sense that spring has sprung when they see and hear a flock of geese flying in the typical V-formation proclaiming the change of season.
Leopold continues . . . . “A cardinal whistling spring to a thaw but later finding himself mistaken, can retrieve his error by resuming his winter silence. A chipmunk, emerging for a sunbath but finding a blizzard, has only to go back to bed. But a migrating goose, staking two hundred miles of black night on the chance of finding a hole in the lake, has no easy chance for retreat. His arrival carries the conviction of a prophet who has burned his bridges.”
It is time to check last year’s
phenology records for the order of events. We can predict that in southern Wisconsin, the red-winged
blackbirds return to the marshes before the end of February and the bluebirds
return to nest by March 15. The wood
frogs begin their choral courtship the third week in March and ground squirrels
and woodchucks emerge sleepy from hibernation by the end of March. Hepatica begins to bloom around mid-April and bloodroot blooms about one week later.
Nature’s grand production runs from the time that skunk
cabbage pokes up through the snow, through the time when the woodpeckers begin
to drum, male red-wings “onk-la-ree” from the cattails and pussy willows fluff
out. Killdeer and meadowlarks return, chipmunks awaken from their winter
dormancy, song sparrows sing “hip hip hooray guys, spring is here,” balls of
garter snakes appear, painted turtles pop up on sunning logs, mourning cloak butterflies
and little brown bats flit about, and spring ephemerals emerge from the woodland floor.
All of these observations were made before April 15th. Soon thereafter the great wave of warbler migration begins (about a month after the woodcocks begin their aerial courtship display). Then the tree leaves burst forth, flowers in gardens and fields bloom and the air holds the sweet scent of lilacs just in time for Mother’s Day. The show continues on and on . . .
“During every week from April to September there are on average, ten wild plants coming into first bloom. . . No man can heed all of these anniversaries; no man can ignore all of them.” - Aldo Leopold
No two years are exactly the same and some signs of spring are more reliable than others. Frogs are good predictors of spring. Wood frogs and spring peepers begin to sing soon after ice-out when the water has warmed to 46 degrees F. Earthworm castings become visible when the frost has come out of the ground. The return of robins and bluebirds is not a reliable indicator of spring because some of them stay in our area throughout the winter.
According to Hopkin’s law, phenological events vary at the rate of one day for each fifteen minutes of latitude, 1.25 days for each degree of longitude, and one day for each one hundred feet of altitude, being later northward, eastward, and upward. When applied in Wisconsin, this law seems to hold almost exactly along a north-south axis; except that Lake Michigan retards the spring warmup.
Above is merely a sampling of the discoveries that await the curious nature observer. It is a fun time of year for each of us to get outside and take a closer look at what Aldo Leopold calls the “hundred little dramas” happening right outside the door when spring is in the air.
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