La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Water temperature and phytophenology indicate the earlier onset of oviposition in Eurasian Dipper (Cinclus cinclus) from the Swiss Lowlands
Auteurs :	J. Hegelbach, Auteur
Type de document :	Article
Dans :	Journal of Ornithology (142(3) JUL 2001)
Article en page(s) :	284-294
Langues:	Anglais
Résumé :	Initiation of reproduction was investigated in Eurasian Dipper (Cinclus cinclus) along riparian habitat of tributaries flowing into lower Lake Zurich (Switzerland). Total length of these drainages is 40 km and Dippers nested from 410 - 680 in asl. From 1992 to 2000 about 46 pairs per year had 552 successful broods with nestlings of at least 8 to 12 days of age. Meterological data (i. e., air temperature, days with rain, amount of rainfall, amount of sunshine) and water temperature in a study area river were obtained from government weather stations. Phytophenological data, i.e. full flowering of Coltsfoot (Tussilago farfara), Wood Anemone (Anemone nemorosa), and Dandelion (Taraxacum officinale), were also available from stations within the study area. Dippers initiated breeding in February or March of each year. with considerable variability among years. Earliest oviposition was 9 February 1995, and again 1997, while latest was 9 March 1992. The median date each year for appearance of the first 25 % of all broods was significantly correlated with February water temperatures (Spearman rank correlation. p

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