Environmental factors affecting the foraging behavior of herons in Ichkeul National Park, Tunisia

Nefla, A. & Nouira, S. 2016. Environmental factors affecting the foraging behavior of herons in Ichkeul National Park, Tunisia. Waterbirds 39: 99–103. doi: 10.1675/063.039.0112

Abstract:

This study was carried out at Ichkeul National Park, Tunisia, during 2009 and 2010. The influence of environmental variables on the foraging behavior of three Ardeid species was studied. Grey Herons (Ardea cinerea) were the least active of the three species, having the greatest resting percentages in 2009 (55.0%) and 2010 (64.9%); they primarily used the “standing and wait” hunting behavior (68.5%). Great Egrets (A. alba) (93.6%) and Little Egrets (Egretta garzetta) (86.5%) primarily adopted a “walking slowly” strategy. Little Egrets also frequently used the “walking quickly” behavior, a more active hunting technique. Both Little and Great egrets varied their hunting behaviors according to water depth. In shallows, they used the “walking quickly” behavior, while in deeper waters they used the “standing and wait” behavior (Little Egret: r = -0.26, P < 0.001; Great Egret: r = -0.44, P < 0.01). For Little Egrets only, high temperature (F = 42.77, df = 1, P < 0.001) and high wind velocity (F = 63.81, df = 1, P < 0.001) promoted an active “walking quickly” hunting behavior, while high light intensity frequently promoted the “standing and wait” and “walking slowly” behaviors (F = 5.48, df = 1, P < 0.05).

Grey Heron (Ardea cinerea) foraging, Ain Yagout, north-east Algeria

Grey Heron (Ardea cinerea) foraging, Ain Yagout, north-east Algeria (Raouf Guechi Nature & Wildlife Photography)

 

Ecologie alimentaire de Sterne hansel (Gelochelidon nilotica) en période de nidification à Sebkha Zima, Maroc

Aourir, M., Radi, M. & Znari, M. (2013). Habitat d’alimentation et régime alimentaire de la Sterne hansel, Gelochelidon nilotica, en période de nidification à Sebkha Zima, centre-ouest du Maroc. Ecologia Mediterranea 39(2): 31-38.   PDF

Résumé :

L’analyse du régime alimentaire par examen de pelotes de réjection au niveau d’une colonie de la Sterne hansel, Gelochelidon nilotica, nichant à Sebkha Zima, centre-ouest du Maroc, a montré un spectre alimentaire réduit chez cette espèce. Son régime alimentaire est caractérisé par la prédominance des proies des régions environnantes du site de nidification. Les invertébrés terrestres : Orthoptères (Acrididés), Coléoptères (Scarabéidés et Lucanidés), des Scorpionidés et les lézards acanthodactyles constituent les proies principales. En revanche, les invertébrés aquatiques Artemiidea et Dytiscidés constituent des proies secondaires.

Poussin de la Sterne hansel (Gelochelidon nilotica )en train d’avaler un Acanthodactyle

Poussin de la Sterne hansel (Gelochelidon nilotica) en train d’avaler un Acanthodactyle (Sebkha Zima, Maroc)

Foraging Habitat and Diet of Gull-billed Tern, Gelochelidon nilotica, during the nesting period in Sebkha Zima, West-central Morocco.

Abstract:

Analysis of pellets from a colony of Gull-billed Terns, Gelochelidon nilotica, nesting in Sebkha Zima, West-central Morocco, revealed a reduced food spectrum in this species. Its diet is predominantly made of preys from areas around the nesting site. Terrestrial invertebrates: Orthoptera (Acrididae), Coleoptera (Scarabeidae and Lucanidae), Scorpionidae along with Acanthodactylus lizards were the major prey items. Aquatic invertebrates rather secondary prey categories.