author(s)
Hadia Rizi, Nadia Ziane, Rachid Rouag and Mohamed Salah Boulaakoud

abstract
The objective of our study is the monitoring of the population of the ferruginous duck (Aythya nyroca) in perinesting and nesting periods over two consecutive years (2006 and 2007). The choice of this species is related to its status of species listed in the red list of the IUCN as threatened, it is also protected by the Algerian legislation as threatened with extinction. The study is conducted on Lac Tonga, Ramsar site and one of the most important wetlands for nesting of Aythya nyroca in North Africa. The weekly and monthly surveys on the change in the number of adults and chicks and the comparison with Boumezbeur data (1993) show an increase in number, which testify for the importance of the Lac Tonga as a nesting site for a large number of waterbirds.