In­crease in Gad­wall num­bers wel­come news

Wicklow People (West Edition) - - LIFESTYLE -

THE de­par­ture of Swal­lows and other sum­mer mi­grants and the ar­rival of au­tumn her­alds the im­mi­nent in­flux of win­ter­ing wa­ter­birds.

Win­ter­ing wa­ter­birds are the species of wild birds that come here an­nu­ally to spend the colder months of the year with us. Our milder oceanic cli­mate at­tracts them when colder parts of main­land Europe are locked in the chilly em­brace of an en­velop­ing blan­ket of ice and/or snow.

Some 800,000 in­di­vid­ual win­ter­ing wa­ter­birds ar­rive here each year com­pris­ing about 70 species. A re­cent re­port on the sta­tus and dis­tri­bu­tion of th­ese win­ter vis­i­tors to our shores found that there has been a re­duc­tion in num­bers in Ire­land of about 15% dur­ing the pe­riod 2012-2016 rel­a­tive to the pre­vi­ous sur­vey pe­riod 2007-2011.

At over 80%, Scaup showed the great­est de­cline. Gold­en­eye and Pochard were down over 50%. Mal­lard, Pin­tail, Red-breasted Mer­ganser, Shov­eler and Tufted Duck were all down by over 25%.

But it wasn’t all bad news. Gad­wall and Lit­tle Egret both showed dra­matic in­creases while Grey Heron and Lit­tle Grebe num­bers were well up.

The in­crease in Gad­wall must be wel­comed as good news but the wel­come has to be damp­ened by the knowl­edge that the species is the duck most as­so­ci­ated with pol­luted wa­ters. Fur­ther­more, the in­crease of 54.9% was cal­cu­lated over a 22-year pe­riod and masks a de­cline of 39.3% dur­ing the most re­cent sur­vey pe­riod (2012-2016).

Smaller and slim­mer than a fe­male Mal­lard, the Gad­wall is an el­e­gant grey­ish-brown dab­bling duck eas­ily recog­nised, es­pe­cially in ma­ture males, by its dis­tinc­tive small white square patch, like a sugar cube, on its side when swim­ming or on the rear of its wings when fly­ing.

The Gad­wall’s diet com­prises mainly seeds and aquatic veg­e­ta­tion with some in­sects.

Male Gad­wall, es­pe­cially in breed­ing plumage, are dis­tinc­tive in that they ex­hibit mark­ings called ver­mic­u­la­tion as fea­tured in the im­age above. A ver­mic­u­la­tion is a mark in the form of a fine wavy line re­sem­bling the track made by a crawl­ing worm. Ver­mic­u­la­tion is a pop­u­lar form of dec­o­ra­tion used in ar­chi­tec­ture where wavy lines are cut into the sur­face of stone to form a re­peat­ing pat­tern.

Gad­wall are not a com­mon duck in Ire­land. About 900 birds win­ter here each year, some 400 in North­ern Ire­land and about 500 scat­tered through­out the Repub­lic. Smaller num­bers of the win­ter­ing birds stay to breed in sum­mer nest­ing in lo­calised ar­eas by shal­low fresh­wa­ter lakes and brack­ish la­goons with abun­dant veg­e­ta­tion.

Male Gad­wall in breed­ing plumage dis­play a strik­ing pat­tern on their breasts.

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