Trends in number of wildfowl Anatidae and coot Fulica atra winteringin France between 1987 and 2003: Is January a sufficient reference?

摘要

The monitoring of widlfowl and Coot numbers in France allows detecting significant trends at medium to short term, a crucial tool for management and conservation. Given the place of the country along the flyway for some species, or its role as a wintering area for others, french numbers are essential for a proper analysis of population trends at the European scale. The monitoring took place at 98 wetlands scattered all over France. Wildfowl and Coot were monitored every winter in mid-December, January and February. We used Log-linear Poisson regressions to estimate missing count using TRIM software. A diagnosis allows assigning the results of a TRIM analysis to one of eight possible trend classes: strong, medium or low decrease, unknown trend, stable numbers, low, medium or strong increase. Among the 20 species studied, Mallard, Coot, Pochard, Goldeneye and Shelduck showed different trends in December, January and February.