Wintering waterbird assemblages in the central part of the Gulf of Gabès in southern Tunisia

Hamza, F., Hammouda, A. & Selmi, S. (2016). Wintering waterbird assemblages in the central part of the Gulf of Gabès in southern Tunisia. Ostrich 87:  217–223. doi: 10.2989/00306525.2016.1207721
PDF

Abstract

Although the Gulf of Gabès is recognised as an Important Bird Area, several aspects of the ecology of waterbirds inhabiting this area still need to be investigated. We observed how waterbird foraging guilds varied among habitats. In total, 49 species belonging to 16 families were recorded. Winter visitors accounted for 73% of counts. The avifauna was dominated by shorebirds (52% of records), followed by large wading birds (25%), open-water birds (18%) and waterfowl (5%). However, the structure of local waterbird communities and their composition in terms of foraging guilds varied according to habitat type. The bird communities of sandy beaches were dominated by open-water birds, whereas large mudflats were dominated by shorebirds, and wadi estuaries showed a more even representation of foraging guilds. Locally rare species had narrow distributions, whereas locally abundant species were found widely within the gulf. For four species the 1% population level criterion of the Ramsar Convention was exceeded. Overall, our results show that the Gulf of Gabès hosts important numbers of waterbirds with different ecological requirements, which confirms the importance of this gulf as a wintering area for Palearctic waterbirds.

Rassemblements hivernaux chez les oiseaux aquatiques de la zone centrale du Golfe de Gabes en Tunisie méridionale

Bien que le Golfe de Gabes soit reconnu comme une zone importante pour la conservation des oiseaux, de nombreux aspects de l’écologie des oiseaux d’eau qui y vivent restent peu connus. Ainsi, l’objectif de ce travail était de décrire la diversité de l’avifaune hivernante dans ce golfe et d’étudier la variation de sa composition, en termes de guildes alimentaires, entre les différents types d’habitat qu’abrite cette région. Au total, 49 espèces appartenant à 16 familles ont été recensées. Les hivernants représentent 73% des effectifs enregistrés. Cette avifaune est dominée par les limicoles (52% des effectifs enregistrés) suivis par les grands échassiers (25%), les laridés (18%) et les canards (5%). Cependant, la structure des communautés locales et leurs compositions en termes de guildes varient en fonction de d’habitat. C’est ainsi que les avifaunes des plages sableuses sont dominées par les laridés, celles des vasières par les limicoles, alors que les estuaires des oueds abritent une avifaune plus équilibrée. Les espèces localement rares ont une répartition restreinte, tandis que les espèces localement abondantes ont une large distribution dans le golfe. D’autre part, pour quatre des espèces recensées, le critère de 1% de la Convention de Ramsar est atteint. Globalement, nos résultats montrent que le Golfe de Gabes abrite un effectif important d’oiseaux d’eau ayant des affinités écologiques variées, ce qui confirme l’importance de ce golfe pour l’avifaune Paléarctique.

Eurasian Spoonbill, Spatule blanche (Platalea leucorodia) ringed in The Netherlands and observed here in gulf of Gabès, Tunisia.

Eurasian Spoonbill, Spatule blanche (Platalea leucorodia). This bird was ringed in summer 2015 in The Netherlands. During the autumn migration, this spoonbill was observed in the gulf of Gabès, Tunisia. Usually, spoonbills from the Netherlands use the East Atlantic flyway and it is uncommon to observe them in Tunisia. This recovery of Dutch spoonbill is the 4th in Tunisia and the first for the gulf of Gabès (Foued HAMZA)

 

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 )

Sexual size dimorphism and morphometric sexing in a North African population of Laughing Doves (Spilopelia senegalensis)

Ayadi, T., Hammouda, A., Kididi, S., Yahyaoui, M. H. & Selmi, S. (2016). Sexual size dimorphism and morphometric sexing in a North African population of Laughing Doves Spilopelia senegalensis. Ostrich 87: 173–177. doi: 10.2989/00306525.2016.1188173

Abstract:

Like the majority of Columbiformes, the Laughing Dove Spilopelia senegalensis is sexually monomorphic in plumage, but seems to be slightly dimorphic in size. However, due to the lack of studies little is known about the sexual size dimorphism in this species. In this work, we used morphometric data on a sample of 61 Laughing Doves from southern Tunisia, and sexed using a DNA-based method, to assess size differences between males and females and to determine a discriminant function useful for sex identification. The results showed that wing length was the most dimorphic trait, which could be due to the effects of sexual selection. The best function for the discrimination between sexes included wing length and head length, which is comparable with findings on other dove species. This discriminant function accurately classified 89% of birds, providing a rapid and accurate tool for sex identification in the studied population. Further data from different populations are needed for firmer conclusions about the extent of sexual size dimorphism and the reliability of the morphometric sexing approach in this dove species.

Assortative mating for carotenoid colouration but not size in the Yellow-legged Gull (Larus michahellis)

Hammouda, A., Hamza, F., Ayadi, T., Pearce-Duvet, J. & Selmi, S. (2016). Assortative mating for carotenoid colouration but not size in the Yellow-legged Gull Larus michahellis. Bird Study 63: 289–292. doi: 10.1080/00063657.2016.1185087
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Abstract:

Mediterranean Yellow-legged GullsYellow-legged Gulls mate assortatively according to carotenoid-based colouration but not in relation to size

In conclusion, our results suggest that carotenoid-based colouration plays a more important role in mate choice than does body size in Mediterranean Yellow-legged Gulls. However, these results might have been impacted by the study’s small sample size. Moreover, our data are descriptive in nature and reveal nothing about potential underlying processes. We thus believe that additional studies involving larger data sets obtained from marked birds and field experiments are necessary to clarify mate choice mechanisms in this species.

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)

 

Predictors of the abundance of shorebirds and wading birds wintering in the Gulf of Gabès, Tunisia

Hamza, F. & Selmi, S. (2015). Habitat features and human presence as predictors of the abundance of shorebirds and wading birds wintering in the Gulf of Gabès, Tunisia. Marine Ecology Progress Series 540: 251–258.  doi: 10.3354/meps11500

Abstract:

Understanding ecological factors and processes affecting waterbird abundance is a major question in ecology and important for conservation purposes. In the Mediterranean, studies dealing with the determinants of waterbird abundance and distribution have mainly been concerned with European coastal habitats, whereas less attention has been paid to coastal areas in North Africa. In this work, we used count data to investigate the relevance of habitat features and human presence as predictors of the abundance of shorebirds and wading birds wintering in the Gulf of Gabès, a particularly important wintering quarter for many Palearctic waterbirds in Tunisia. We found that the strength and direction of the relationships between bird abundance and both habitat and human parameters varied among species, depending on their ecological requirements. Most species occurred more abundantly in large mudflats compared to narrow sandy beaches, while one species showed an opposite trend. We also found that the studied sites were frequently visited by local people, mainly for clam harvesting, thus sharing the intertidal habitats with birds. However, the abundance of most species did not decrease with increasing human presence, suggesting that traditional clam-harvesting activity did not seem to disturb birds. Nonetheless, we believe that further investigations of the interactions between birds and clam-harvesters are needed to better understand the role of traditional clam-harvesting activity in shaping the abundance and diversity of waterbirds wintering in the Gulf of Gabès.

Related papers (PDFs):

  • Sanderling (Calidris alba) colour-ringed in Iceland, and observed wintering in the Gulf of Gabès, Tunisia (Foued Hamza / Birding in Tunisia).
    Sanderling (Calidris alba) colour-ringed in Iceland, and observed wintering in the Gulf of Gabès, Tunisia (Foued Hamza / Birding in Tunisia).

Open trade in protected raptors at Souk Moncef Bey, Tunis

التجارة غير المشروعة في الطيور الجارحة المحمية بسوق المنصف باي، في تونس العاصمة

هذه بعض الصور التي التقطها أحد أفراد الجمعية التونسية للحفاظ على الحياة البرية يوم أمس بسوق المنصف باي الذي أصبح مكانا معتادا للمتاجرة بالأنواع المحميّة و المهدّدة بالإنقراض مثل هذه الصقور. التجاوزات تتم جهرة و بدون خشية من القانون تضيف الجمعية في صفحتها على الفايسبوك

Commerce illégal des rapaces protégées au Souk Moncef Bey, Tunis

Voici quelques photos prises par un membre de l’association Tunisia Wildlife Conservation Society (TWCS) hier (27 décembre 2015) au Souk Moncef Bey, qui est devenu une place familière pour la vente des espèces menacées et protégées. “Les abus sont ouverts et sans crainte de la loi” ajoute l’association TWCS dans sa page facebook.

Lire aussi:

1) Faune sauvage en vente à Tunis, par Mr Abdelmajid Dabbar

2) Nos oiseaux victimes du commerce sur internet (Algérie)

3) Trafic d’oiseaux sur Internet en Algérie et au Maroc

4) Trafic illégal des espèces sauvages protégées en Algérie via l’Internet

Faucon pèlerin (Falco peregrinus), Souk Moncef Bey, Tunis (Tunisia Wildlife Conservation Society, TWCS)

Faucon pèlerin (Falco peregrinus), Souk Moncef Bey, Tunis, 27 décembre 2015 (Tunisia Wildlife Conservation Society, TWCS)

Faucon lanier (Falco biarmicus), Souk Moncef Bey, Tunis (Tunisia Wildlife Conservation Society, TWCS)

Faucon lanier (Falco biarmicus), Souk Moncef Bey, Tunis, 27 décembre 2015 (Tunisia Wildlife Conservation Society, TWCS)

Un indice écologique pour la surveillance des zones humides basé sur l’avifaune aquatique : cas de la Tunisie

Hamdi, N. & Ismail-Hamdi, S. (2015). Un indice écologique pour la surveillance des zones humides basé sur l’avifaune aquatique : cas de la Tunisie. Revue d’Ecologie (Terre et Vie): 328–342.

Resumé :

Nous proposons dans ce travail un indice écologique pour la surveillance des zones humides tunisiennes, basé sur la variation des effectifs annuels moyens d’oiseaux d’eau. Ce nouvel outil offre une méthode applicable à la surveillance de toutes les catégories de zones humides du Nord de l’Afrique ayant des similitudes avifaunistiques et hydrologiques. Cet indice écologique se calcule en quatre étapes : (1) discriminer les zones humides en associations partageant des caractéristiques hydro-écologiques communes ; (2) déterminer la valeur indicatrice de chaque espèce sur ces différentes associations, quantifiant la relation d’une espèce à l’une des associations ; (3) calculer les variations temporelles des effectifs moyens de chacune de ces espèces entre deux périodes de suivi (dans notre cas 1970/2000 et 2001/2013) ; (4) calculer la somme pondérée des produits des deux métriques de toutes les espèces indicatrices pour chaque association. L’application de notre indice aux zones humides tunisiennes suggère une dégradation des conditions d’hivernage des lagunes et des sebkhas ainsi que des milieux côtiers. À l’inverse, les conditions d’hivernage dans les plaines inondées et les garaets semblent s’améliorer, notamment pour les espèces anthropophiles. Cette méthode de surveillance des zones humides constitue un nouvel outil de travail simple et efficace pour les professionnels de l’environnement.

Abstract:

Waterbirds as an ecological indicator for monitoring wetlands: an application to Tunisia.

We propose a simple ecological index to monitor wetlands, based on interannual changes in waterbird numbers and the hydro-ecological characteristics of their wintering sites. This new method provides a simple tool applicable to most types of wetlands in northern Africa with comparable waterbird species and hydrological attributes. Scores of this ecological index are calculated through a four-steps approach: (1) discriminate prospected sites into different associations based on their hydro-ecological characteristics; (2) compute indicator values for each waterbird species considered to quantify the strength of species-habitat relationships in each wetland associations; (3) calculate the relative rate of temporal change in indicator species abundances between two sampling events (in our example 2001-2013 and 1970/2000); (4) compute the weighted sum across species of the product of these two metrics within a given wetlands association. The application of our index to the monitoring of Tunisian wetlands suggests the degradation of wintering lagoons and salt pans and coastal environments. Nevertheless, applying the index in floodplains and garaets tends to indicate improved overwintering conditions, especially for man-tolerant waterbird species. Our new index targets environmental stakeholders seeking for an efficient tool for biodiversity monitoring.

 

Species richness patterns of waterbirds wintering in the gulf of Gabès in relation to habitat and anthropogenic features

Hamza, F., Hammouda, A. & Selmi, S. (2015). Species richness patterns of waterbirds wintering in the gulf of Gabès in relation to habitat and anthropogenic features. Estuarine, Coastal and Shelf Science 165: 254-260.
doi: 10.1016/j.ecss.2015.05.025
PDF in ResearchGate.net

Abstract:

Identifying factors affecting waterbird diversity is a major topic in avian ecology, as well as for conservation purposes. In this work, we investigated the relevance of habitat features and human presence in predicting the diversity of waterbirds wintering in the gulf of Gabès, an important but poorly known wintering area of palearctic waterbirds. This includes two major sources of bias in macroecological studies, namely species imperfect detection and spatial non-independence among sampled communities. Our results showed that species richness overall varied among sites according to habitat quality and tidal area use by humans. In particular, large intertidal areas, characterized by high numbers of tidal channels, elevated amounts of mud and organic materials in the sediment and important coverage of seagrass, hosted a greater diversity of waterbirds with different ecological requirements than did the small and relatively homogeneous sandy beaches. Moreover, we found that intertidal area use by humans for clam harvesting was associated with high diversity of waterbirds, particularly shorebirds, suggesting positive effects of clam harvesting on shorebirds. Further investigations of habitat selection processes and foraging behaviors are however needed to more profoundly understand the role of traditional human activities in the intertidal areas of the gulf of Gabès in shaping wintering waterbird communities.

Calidris alba (Sanderling - Bécasseau sanderling): ringed in Iceland in 2011, and wintering in the Gulf of Gabès, Tunisia

Sanderling (Calidris alba). This bird was ringed in Iceland in 2011, and wintering in the gulf of Gabès, Tunisia, January 2013. (Foued Hamza / Birding in Tunisia).

Atlas Pied Flycatcher: variability of identification characters

Deux articles qui traitent l’identification de Gobemouche de l’Atlas (Ficedula speculigera) et les espèces similaires: Gobemouche noir européen (F.h. hypoleuca) et ibérique (F.h. iberiae), Gobemouche à collier (F. albicollis) et les hybrides albicollis x hypoleuca

Two articles dealing with field identification of the Atlas Pied Flycatcher (Ficedula speculigera) and similar species.

The first article is about the variability of plumage and morphology of the Atlas Pied Flycatcher and the overlapping characters with the Iberian Pied Flycatcher (Ficedula h. iberiae) and other similar species: European Pied Flycatcher (Ficedula h. hypoleuca), Collared Flycatcher (Ficedula albicollis) and also hybrids albicollis x hypoleuca.

Corso, A., Janni, O., Viganò, M. & Starnini, L. (2015). Atlas Pied Flycatcher: variability of identification characters. Dutch Birding 37: 141–160.
PDF in ResearchGate.net

A second article about the call identification:

Robb, M. & The Sound Approach (2015). Call identification of European Pied, Iberian Pied and Atlas Pied Flycatcher. Dutch Birding 37: 161–163.

Atlas Pied Flycatchers Ficedula speculigera (Lorenzo Starnini). Images from birds on breeding grounds in Morocco and Tunisia in May

Atlas Pied Flycatchers Ficedula speculigera (Lorenzo Starnini). Images from birds on
breeding grounds in Morocco and Tunisia in May. From figure 1 of Corso et al. Dutch Birding 37: 141–160.