Ecological characteristics of the reproduction of the nyroca duck (Aythya nyroca) breeding in lake Tonga (Northeast of Algeria)

The habitats and ecosystems of the Mediterranean Sea are of prime strategic interest both ecologically and economically. The Ferruginous duck, a species widely distributed in Africa, Europe and Asia, these numbers have experienced declines and changes in distribution in recent decades. The primary reasons for these declines are mainly due to habitat degradation and loss and hunting for local consumption (Robinson & Hughes 2003).

Our study was carried out on the Ferruginous Duck (Aythya nyroca) in Lake Tonga (El Kala National Park), during the period from September 2020 to August 2021. This duck classified as a near threatened species (IUCN, Red list 2022), a regular breeder in this body of water.

We observed the evolution of the numbers of this species during the wintering season, the maximum of 830 of which was noted during the month of December. This Anatidae also prefers to install its nests on islands of Typha angustifolia with a rate of 64%.

It appears that the date of the beginning of the laying is estimated towards the end of April, the nests contain on average 10 to 12 eggs with a maximum of 23 eggs. The monitoring of biometric parameters exposes us to very variable measurements, i.e., an external diameter of 25.8cm [18-35.5], an internal diameter of 16.46cm [12.5-22], a depth of 9.44cm [4.5-17], an elevation of the nests compared to the water around 11.75cm [4-20] and an average inter-nest distance of 5cm [1.75-22.84].