Glutz von Blotzheim, U.
(* = Kurzbeitrag)
Die Wasservögel und Limikolen des Urnersees: Phänologie, Bestandsentwicklung, home range-Nutzung, Legebeginn, Bruterfolg und anthropogene Einflüsse.
(von 1994 bis 2006 vergeben)
Winterbestand, Brutbestand, Wasserstandsschwankungen, Flachwasserzone, Legebeginn, Zweitbrut, Ersatzgelege, Bruterfolg, Naturschutzgebiet, Störungen
Podiceps cristatus,Tachybaptus ruficollis, Cygnus olor, Anas platyrhynchos, Netta rufina, Aythya ferina, Aythya fuligula, Somateria mollissima, Mergus merganser, Rallus aquaticus, Gallinula chloropus, Fulica atra, Charadrius dubius, Larus michahellis, Larus fuscus intermedius, Gavia arctica, Podiceps grisegena, Podiceps nigricollis, Phalacrocorax carbo, Anser fabalis, Anser albifrons, Anser anser, Tadorna tadorna, Anas penelope, Anas strepera, Anas crecca, Anas acuta, Anas querquedula, Anas clypeata, Anas nyroca, Aythya marila, Clangula hyemalis, Bucephala clangula, Vanellus vanellus, Calidris alpina, Calidris alba, Gallinago gallinago, Limosa lapponica, Numenius arquata, Tringa erythropus, Tringa totanus, Tringa nebularia, Tringa ochropus, Tringa glareola, Actitis hypoleucos, Larus atricilla, Larus ridibundus, Larus melanocephalus, Larus minutus, Larus canus, Larus argentatus, Larus cachinnans, Sterna albifrons, Chlidonias niger, Branta canadensis, Branta leucopsis, Tadorna ferruginea, Aix sponsa, Aix galericulata, Anas sibilatrix
Haubentaucher, Zwergtaucher, Höckerschwan, Stockente, Kolbenente, Tafelente, Reiherente, Eiderente, Gänsesäger, Wasserralle, Teichhuhn, Blässhuhn, Flussregenpfeifer, Mittelmeermöwe, Heringsmöwe, Prachttaucher, Rothalstaucher, Schwarzhalstaucher, Kor-moran, Saatgans, Blässgans, Graugans, Brandgans, Pfeifente, Schnatterente, Krickente, Spiessente, Knäkente, Löffelente, Moorente, Bergente, Eisente, Schellente, Kiebitz, Alpenstrandläufer, Sanderling, Bekassine, Pfuhlschnepfe, Grosser Brachvogel, Dunkler Was-serläufer, Rotschenkel, Grünschenkel, Waldwasserläufer, Bruchwasserläufer, Flussuferläufer, Aztekenmöwe, Lachmöwe, Schwarz-kopfmöwe, Zwergmöwe, Sturmmöwe, Silbermöwe, Steppenmöwe, Zwergseeschwalbe, Trauerseeschwalbe, Kanadagans, Weisswan-gengans, Rostgans, Brautente, Mandarinente, Chile-Pfeifente
Schweiz, Urnersee, Reussdelta, Uri, Brunnen, Muota, Schwyz
Waterbirds and waders among the southernmost oligotrophic part of Lake of Lucerne. The southernmost basin of the Vierwaldstättersee (Lake of Lucerne) called Urnersee (Lake of Uri) is from the ornithological point of view at least of regional conservation concern. The Urnersee covers some 26.8 km2, is situated between steep slopes, has a maximum depth of 199 m, is poor in nutrients and has only two very small delta areas (together some 0.6 km2) with a water depth of less than 5 m. Waterbirds, waders and gulls concentrate mainly on these two delta areas.
The small number of birds allows censusing the year round and investigating reasonably accurately laying time and breeding success. Common Pochard, Tufted Duck and Eurasian Coot are decreasing as wintering birds since the late 1980s. Gadwall and Red-crested Pochard have increased on a very low level. The wintering population of Little Grebe is surprisingly high, those of the Goosander lower than expected.
The beginning of egg-laying by Mallard has not changed since the 1950s in spite of some years with higher spring temperatures. The earliest clutches of Red-crested Pochards belong to the earliest found until now in Central Europe. Coots begin laying about a month earlier on a small channel crossing the centre of Brunnen than on the reed-beds in the two delta regions where nests are suffering from wind and oscillation of water-levels. The breeding success of ducks and coots is poor, but increases towards the end of the breeding season thanks to a more stable water-level and decreasing predation presumably by Yellow-legged Gull. The Yellow-legged Gull is breeding since 2000 on small islets on the southernmost edge of Urnersee. Up to 2012 the number of breeding pairs increased to more than 50. Most young leave the birthplace soon after fledging, so that the numbers still present from July to November did not really increase from 2003 to 2011.
The annual home range of the few Common Eiders (5 ♂, 1 ♀) remaining probably from the last of three remarkable influxes between 1959 and 1988 covers the whole surface of the Urnersee. The ducks are moving in short intervals between the river mouths of Reuss and Muota, a distance of approximately 11 km. During the moulting season the flock breaks up and the main place of residence is not yet known.
The Little Ringed Plover is the only wader species breeding, but in spite of 2 to 3 pairs with extremely poor success. Apart from Common Sandpiper, migrating waders on rest are extremely scarce; the supposed reasons for this fact are the situation of the lake within the Northern Alps, the lack of food on the ever moving young sandbeaches and too many disturbances in spite of nature reserves, which are too small. The possibilities of improving the significance are discussed, but do not show great promise. Much more important are therefore controlled visitor guidance and the establishment of small lagoons or ponds inland if this southernmost basin of Lake of Lucerne should maintain some significance for waterbirds and people interested in it.
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