greater greater europe colloquially north_america mid sized diving duck larger closely related lesser spends summer months breeding alaska northern canada siberia northernmost reaches europe winter south coasts north_america europe japan drake greater larger rounded heads females bright blue bill yellow eyes heads dark green breast black belly white wing shows white stripe females brown white wing dull blue bills white face greater nest near water typically islands northern lakes floating vegetation begin breeding age start building nests year complex courtship takes place return migration summer breeding grounds concludes formation pairs females lay clutch olive buff colored eggs eggs hatch days covered able follow mother search food immediately hatching greater eat aquatic plants insects obtain diving underwater form large groups called number thousands main threat human development preyed humans greater populations declining 1980s listed species concern iucn red list taxonomy genus derived ancient greek refers mentioned aristotle thought refer duck species greek word coal dust greater studied male greater america distinguishable europe asia stronger worm like carvings marks mantle considered separate subspecies females subspecies indistinguishable based size differences pleistocene described fossils recovered greater come scottish northern english word bed duck mating phylogenetic analysis diving ducks examining skeletal anatomy skin found greater lesser closest relatives duck closest relative pair description adult greater long wingspan body mass blue bill yellow eyes heavier longer closely related lesser male dark head green black breast light black tail white underside drake male greater larger rounded head female drake belly flanks bright white neck breast tail feathers glossy black lower flanks gray upper wing white stripe starting extending flight feathers legs feet sexes gray adult female brown body head white wing markings similar male slightly white band brown oval shaped patches base bill slightly shade blue drake juvenile greater look similar adult females greater drake eclipse plumage looks similar breeding plumage pale parts plumage gray distinguishing greater lesser difficult field head greater tends rounded white wing stripe extensive distribution habitat greater distribution breeding north_america spends summer months alaska siberia northern parts europe found asia present year round summer habitat lowland islands fresh water lakes fall greater populations start migration south winter winter pacific atlantic coasts north_america coasts northwest europe black_sea coast japan winter months found coastal bays inland lakes lakes great lakes europe greater breeds iceland northern coasts scandinavian peninsula including northern parts baltic_sea higher mountains scandinavia areas close russia birds spend winters british isles western norway southern tip sweden coast brittany poland including denmark alps eastern adriatic_sea northern western black sea southwestern north_america greater summers newfoundland northern northern northern winters coasts north_america northern british_columbia south nova_scotia new_brunswick south florida shores great lakes gulf_of_mexico behaviour breeding greater breed forest estimated north american population breed alaska typically nest islands large northern lakes greater begin breeding years old start nesting age drake greater soft quick whistle use attract attention courtship takes place late winter early spring way northern breeding grounds female greater single pitch courtship complex results formation pairs pairs nest close proximity large colonies usually near water island shoreline floating vegetation nest consists shallow depression female lined female lays eggs drake female goes large isolated lake lakes close breeding grounds miles away lakes chosen yearly ducks optimal lake fairly shallow abundance food sources cover female lays olive buff colored eggs days larger clutch indicate brood greater ducks species newly hatched chicks covered soon able walk swim feed able fly days hatching vulnerable small chicks follow mother protects predators feeding greater dive obtain food eat surface mainly eat aquatic plants aquatic insects summer months greater eat small aquatic crustaceans report greater leopard frogs body length freshwater pond freshwater ecosystems greater eat seeds leaves stems roots wild owing greater feet weight dive metres stay submerged minute allowing reach food sources diving ducks greater forms large flocks contain thousands birds flocks water face current ducks float backwards fly flock maintain position threats common predators greater humans greater find fishing nets large numbers nets year greater catch future potential threaten greater populations greater faces numerous threats significant challenge survival habitat degradation caused mix human development runoff greater winter threatened escalated levels oil sewage pollution threaten duck greater population winters ducks subject high levels organic increased levels heavy metals foods habitat joint group american canadian scientists researching migration great lakes found female greater female lesser escalated levels bodies occurring trace element occurs naturally soils minute amounts necessary animal life excessive cause reproductive harm highly toxic migration great lakes greater risk eating invasive render causing population decrease study traces iron copper lead tissue samples varying concentrations metals different types tissues analysis revealed highest levels liver highest levels copper liver stomach highest levels lungs liver highest levels iron difference concentration comparing conservation greater rated species concern iucn aerial population surveys greater lesser counted look identical air estimated greater continental population 1980s populations steadily decreasing primary factors contributing decline habitat loss changes breeding habitat lower female survival rate american population survey million worldwide greater population survey estimated mature greater aerial population surveys banding program greater metal leg bands placed killed hunter captured banding group number band reported wildlife organizations banding programs yield valuable data migration patterns harvest rates survival rates human interactions greater popular game bird north_america europe hunted denmark germany greece france united_kingdom ireland iran sport commercial reasons greater hunted shot fly challenging task fly mph greater hunted open water hunting layout boats low profile like boats hunters lie inside hunters frequently use attract birds arranged simulate greater featuring open area attract birds land countries greater hunted duck stamp required normal hunting required pursue game america canada hunted non toxic shot
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