WA­TER­SIDE WILDLIFE

We think of au­tumn colours as go­ing from green to brown, but drakes have dif­fer­ent ideas, says Pip Web­ster

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Go­ing green for au­tumn

Every­one must take time to sit and watch the leaves turn” (Eliz­a­beth Lawrence)… From tired greens to shades of ochre, au­tumn can be a beau­ti­ful sea­son with its many moods and car­pets of fallen leaves – lovely to scrunch through, though not such fun to clear off your nar­row­boat.

Wild cherry and dog­wood in the hedgerows stand out in shades of pink, red or even crim­son, but most of our na­tive Bri­tish trees turn yel­low or brown. The small lobed leaves of field maple turn a par­tic­u­larly vi­brant yel­low while the more sub­tle ash turns light green, then yel­low.

Ash leaves can fall very sud­denly leav­ing the tree still hold­ing on to bunches of ash ‘keys’ (dry brown winged seeds) on its bare branches. The op­po­site ex­treme is seen in beech, where the tree hangs on tena­ciously to its or­angey-bronze leaves of­ten through to the win­ter.

De­creas­ing day length trig­gers the pro­duc­tion of the glo­ri­ous au­tumn colours. Wa­ter is lost through the broad leaves of de­cid­u­ous trees and avail­able wa­ter can be sur­pris­ingly scarce in the harsh win­ter months when the ground is frozen.

Sun­light to syn­the­sise sug­ars is also of­ten in short sup­ply, so the tree loses its leaves and be­comes dor­mant. The green colour fades away as chloro­phyll (the chem­i­cal re­spon­si­ble for cap­tur­ing the en­ergy of sun­light) is bro­ken down, re­veal­ing the un­der­ly­ing yel­lows and or­anges of the more sta­ble carotene pig­ments. The tree re­sorbs many use­ful chem­i­cals be­fore a corky ab­scis­sion layer even­tu­ally seals off the leaves from the twigs and the leaves fall.

The most spec­tac­u­lar au­tumn colours are pro­duced when dry sunny days are ac­com­pa­nied by cool, crisp nights. Late high lev­els of sugar fa­cil­i­tate the syn­the­sis in some species of an­tho­cyanins, with their deeper red and pur­ple colours. Sealed off in the dy­ing leaf, they add spec­tac­u­lar colour to au­tumn: “asec­ond spring when ev­ery leaf is a flower” (Al­bert Ca­mus).

While leaves turn from green to brown, male mal­lards do the re­verse, emerg­ing from their moult­ing or ‘eclipse’ plumage by the end of Septem­ber to sport those mag­nif­i­cent glossy dark green heads, one of sev­eral meth­ods em­ployed to at­tract the at­ten­tion of the still drab-look­ing fe­males.

Al­though se­ri­ous pair­ing of­ten does not oc­cur un­til early spring you can still en­joy watch­ing plenty of courtship dis­plays dur­ing Oc­to­ber. The drakes will flick their heads and jab their bills into the wa­ter, splash­ing and show­ing off their black, curled tail feath­ers. When ap­proached by a fe­male, the drake of­ten re­sponds by tuck­ing his head down to his ch­est and rear­ing the front half of his body right out of the wa­ter and emit­ting a low grunt, im­me­di­ately fol­lowed by a whis­tle. Drakes can ut­ter an oc­ca­sional wheezy quack, but only the fe­males pro­duce that se­ries of noisy but di­min­ish­ing nag­ging sounds like a belly laugh.

Our res­i­dent Bri­tish mal­lards are joined in Oc­to­ber by many mi­grants from Ice­land and north­ern Europe, come to over-win­ter in our milder cli­mate. The males tend to ar­rive first, leav­ing the fe­males com­plet­ing the task of rear­ing the pre­vi­ous sea­son’s young.

Mal­lards are dab­bling ducks – shal­low wa­ter ducks that feed pri­mar­ily along the sur­face or by tip­ping head­first into the wa­ter. The in­side of their beaks have tiny rows of plates (lamel­lae) through which they can fil­ter the wa­ter, trap­ping food – you have prob­a­bly no­ticed the rough­ness of a mal­lard’s beak if you have been nipped by one when it takes food from your fin­gers. Mal­lards are om­niv­o­rous, eat­ing plant mat­ter, in­sects and worms. They dive in­fre­quently – of­ten just to avoid pre­da­tion – and are equally happy grazing on the land.

Mal­lards are the species most of­ten called “wild ducks” – and that state­ment is a real et­y­mo­log­i­cal tan­gle. “Ducks” are fe­male. “Mal­lard” is thought to de­rive from the old French ‘malart’ for wild drake (male) and orig­i­nally re­ferred to any species of wild drake.

En­joy au­tumn’s beau­ties.

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