Diet of chicks of Cattle EgretsBubulcus ibisin the lower Soummam valley, Algeria

Abstract

The diet of Cattle Egret chicks in the lower Soummam valley, Algeria, was investigated in 1998 and 2006, when 145 and 23 regurgitates were collected, respectively. In 1998, 1 698 individual prey items were identified. Insects formed the bulk of the diet of chicks: 94% in terms of frequency, 71% in terms of mass. Orthopterans were dominant, especially in terms of biomass (22% by frequency, 58% by mass), whilst Dipterans were well represented in numbers (59% by frequency). Vertebrates, despite their lesser frequency (3%), contributed 23% by mass of the diet. In 2006, 441 prey items were identified. The contribution of insects decreased to 79% by frequency and 15% by mass (mostly Orthopterans) but vertebrates made up a higher frequency: 20% of prey items and 85% by mass of the diet. The availability of prey items was not correlated to their occurrence in the diet, suggesting that the Cattle Egret is a selective predator, with adults selecting prey species for their chicks. A drought in the spring of 2006 increased the availability of fish and lizards to the Cattle Egrets.

How food supply in rubbish dumps affects the breeding success and offspring mortality of cattle Egret Bubulcus ibis?

“…12 Indeed, B. ibis is a food opportunist, and its diet mainly composed of insects, is complimented by Amphibians, Reptilian and small Mammals; it is known as a predatory bird. [13][14][15][16] The species invasion is favored by the creation of numerous and favorable feeding habitats (irrigation, agriculture), above all, the highly developed specific alimentary opportunism. 11,17 In addition to climate change, the rapidly increasing human population causes an increase in food demand and further increase in intensive agricultural land use, which is significantly correlated to Cattle Egret expansion.…”