Co-occurrence and commensal feeding between Little Egrets (Egretta garzetta) and Eurasian Spoonbills (Platalea leucorodia)

Hamza, F., & Selmi, S. (2016). Co-occurrence and commensal feeding between Little Egrets Egretta garzetta and Eurasian Spoonbills Platalea leucorodia. Bird Study 63: 509–515. doi: 10.1080/00063657.2016.1238035
PDF in RresearchGate

Abstract:

Capsule: The spatial distribution and feeding efficiency of Little Egrets Egretta garzetta wintering in the gulf of Gabès, Tunisia, are affected by a commensal association with the Eurasian Spoonbills Platalea leucorodia.

Aims: To investigate the role of the interspecific interaction between Little Egrets and Eurasian Spoonbills in shaping the spatial distribution and feeding efficiency of Little Egrets.

Methods: Using count and behavioural data, we examined the co-occurrence of these species in flocks, and compared the foraging efficiency of Little Egrets feeding with Eurasian Spoonbills with that of solitary Little Egrets.

Results: We found that the presence of Eurasian Spoonbills doubled the chance of Little Egrets being present. Within mixed flocks, the number of Little Egrets increased with the number of Spoonbills. Moreover, Little Egrets foraging in association with Eurasian Spoonbills took fewer steps, had higher pecking rates and higher prey intake rates than solitary Little Egrets.

Conclusion: Little Egrets appear to obtain foraging efficiency benefits by following Eurasian Spoonbills. This interaction seems to play a role in determining the spatial distribution of Little Egrets.

 

Eurasian Spoonbills (Platalea leucorodia), Gulf of Gabès, Tunisia (Csaba Pigniczki )

Eurasian Spoonbills (Platalea leucorodia), Gulf of Gabès, Tunisia (Csaba Pigniczki )

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)

 

Place des insectes dans les régimes alimentaires de trois Ardéidés en Tunisie septentrionale

Nefla, A., Tlili, W., Ouni, R. & Nouira, S. 2014. Place des insectes dans les régimes alimentaires de trois Ardéidés en Tunisie septentrionale. Alauda 82 (3): 221-232.  PDF

Abstract:

Insects in the diet of three Ardeidae species in Tunisia.

Analysis of 594 pellets of three heron species (Little Egret Egretta garzetta, Cattle Egret Bubulcus ibis and Squacco Heron Ardeola ralloides) collected at colonies in northern Tunisia (Ichkeul National Park, Lebna Dam and Chikli Island). Cattle Egrets consumed preferably insects (most important group in number and biomass), vertebrates did not exceed 1 % and 2 % (in number) and 4 % and 9 % (in biomass) respectively at Ichkeul and Lebna. The diet consisted in Coleoptera, Orthoptera (Caelifera, Gryllidae, Gryllotalapidae) and Hymenoptera (ants). Squacco heron nestlings were fed with annelids, crustaceans and mainly insects (62 % in number and 77 % in biomass) which included larvas of Odonata, Orthoptera (grasshoppers and crickets), Dermaptera (Forficula), Coleoptera and Hymenoptera. The diet of Little Egret consisted mainly in insects (76 % at Ichkeul, 98 % at Chikli). However the percentages of fish did not exceed 10 % and 2 % at both sites respectively.

Related articles:

Mohammedi, A. & Doumandji, S. 2013. Le statut des proies du Héron garde-bœufs (Bubulcus ibis L.) dans la région de Chlef (Algérie). Revue d’écologie 68: 283-289.

Nefla, A., Tlili, W., Ouni, R., & Nouira, S. 2014. Breeding Biology of Squacco Herons (Ardeola ralloides) in Northern Tunisia. Wilson Journal of Ornithology 126 (2): 393–401.

Ouni, R., Nefla, A., El Hili, A., & Nouira, S. 2011. Les populations d’Ardéidés nicheurs en Tunisie. Alauda 79 (2): 157–166.  (PDF)

Heronry of Lebna Dam in Cap Bon, Tunisia

Heronry of Lebna Dam in Cap Bon, Tunisia

Nidification mixte du Héron garde-bœufs et de l’Aigrette garzette sur l’île de Rachgoun en Algérie

Ghermaoui, M., Hassaine, K. & Moulaï, R. (2013). Première observation d’une nidification mixte du Héron garde-bœufs Bubulcus ibis et de l’Aigrette garzette Egretta garzetta en milieu insulaire sur l’île de Rachgoun en Algérie. Alauda 81 (4): 311-312.  PDF

First observation of a mixed breeding colony of Cattle and Little Egrets at Rachgoun Island, Algeria.

Île Rachgoun, ouest algérien

Île Rachgoun, ouest algérien