Diet of adult Cattle Egrets Bubulcus ibis in a new North African colony (Soummam, Cabilia, Argeria): taxonomic composition and sensorial variability

Full article

Published:

Volume 48(2), December 2001. Pages 217-223.

Language:

English

Keywords:

Argelia, biodiversidad, Bubulcus ibis, dieta, Garcilla Bueyera, Soummam Kabylie

Abstract:

We examined 100 pellets regurgitated by adult Cattle Egrets Bubulcus ibis and collected monthly between May 1996 and February 1997 in an area of Soummam Kabylie, Algeria. We analyzed some 11000 fragments and identified 3493 individual prey animals of 73 species or genera, 35 families and 12 orders. The prey biomass per pellet was on average 62.25 g of fresh weight, which corresponds to mean daily consumption. Insects were the most common prey (99.0 % in number and 73.3 % in biomass). Orthoptera were the main insect prey (63.2% in numbers and 53.6% in biomass). Vertebrates (Rodentia, Muridae) accounted for only 0.8% of prey items and 26.2% of the total biomass. The diet was highly variable between seasons, both quantitatively and qualitatively. The prey diversity (Shannon index) was inversely related to its biomass. During the year cycle, the species showed a high adaptability and ecological plasticity in a newly colonized area. To our knowledge, this is the first diet study of adult Cattle Egrets based only on the examination of pellets.