Range expansion of nesting Squacco Heron Ardeola ralloides and Black-crowned Night Heron Nycticorax nycticorax in the Sahara

From a few strongholds in the 19th century, herons and egrets spread across the Algerian coastal strip of North Africa and colonised the Algerian Hauts Plateaux in the second half of the 20th century. Here we report the first breeding of Squacco Heron Ardeola ralloides and Black-crowned Night-Heron Nycticorax nycticorax in a mixed colony at Kef Doukhane, an artificial wetland near Ghardaïa in the northern Sahara. We recorded nine Squacco Heron nests with 37 eggs, with clutch sizes ranging from 1 to 5 eggs (mean = 4.1 + 1.3; N = 9), and three Black-crowned Night-Heron clutches with 3 eggs each. After the first three Squacco Heron clutches hatched, all other nests were wantonly plundered by children in search of eggs and the entire colony was abandoned. The expansion of artificial wetlands in the Sahara and possibly climate change have facilitated the successful colonisation of the Sahara Desert by herons and egrets, but human disturbance and vandalism due to economic hardship and lack of environmental education are currently the major obstacles to range expansion.