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)

 

Significant population of Egyptian Vulture (Neophron percnopterus) found in Morocco

Amezian, M. & El Khamlichi, R. 2016. Significant population of Egyptian Vulture Neophron percnopterus found in Morocco. Ostrich 87: 73–76.

Abstract:

The Egyptian Vulture Neophron percnopterus population in Morocco has undergone a marked decline since the 1980s to the point of nearing local extinction in the twenty-first century. A field study of some possible sites for Egyptian Vultures was carried out over six days during June 2014 in the Middle Atlas Mountains, Morocco. We counted a total of 48 Egyptian Vultures at three different localities: two occupied breeding sites and one communal roost that hosted 40 vultures of different ages. A (probable) singe adult bird at the breeding site was located and a previously occupied site was also visited. A preliminary survey amongst local people indicated that threats faced by this species are predator poisoning in some areas, and the use of vulture parts for traditional medicine. Given that the species is considered globally Endangered and populations continue to decline in many areas, the discovered population reported here, although relatively small, is of national and regional (North-west Africa) importance. We expect this new situation will revive the hopes for studying and conserving this and other vulture species in Morocco and North-west Africa in general.

More details / Plus de détails:

The plight of the Egyptian Vulture and hopes for the future.

Traduit aussi en français: Les vautours au Maghreb: une situation critique et espoirs pour l’avenir.

Videos of the communal roost of Egyptian Vultures,  Morocco / Dortoir de Vautours percnoptères:

Adult Egyptian Vulture (Neophron percnopterus), Middle Atlas, Morocco
Egyptian Vulture (Neophron percnopterus), Middle Atlas, Morocco.

Breeding ecology of Turtle Doves (Streptopelia turtur) on intensively cultivated farmland

Hanane, S. (2016). Effects of location, orchard type, laying period and nest position on the reproductive performance of Turtle Doves (Streptopelia turtur) on intensively cultivated farmland. Avian Research 7: 4.  doi: 10.1186/s40657-016-0039-0 (Open Access)

Abstract

Background
Until recently little was known about factors affecting reproductive parameters of the Turtle Dove (Streptopelia turtur) on intensively cultivated farmland in the Mediterranean area. In this study, the reproductive parameters of this game species were evaluated in relation to location, orchard type, laying period and nest position in central Morocco.

Methods
A total of 317 nests were found and analyzed across five breeding seasons (2004–2008) in the Haouz and Tadla regions, over two major agro-ecosystems made up of olive and orange orchards. Nest position, laying period, clutch size and the number of chicks hatched and fledged per nest were determined on 120 study plots. I used Generalized Linear Models (GLMs) with a Poisson distribution and a log link function, including the logarithm of the number of eggs in each clutch as an offset to model the number of chicks hatched and fledged per nest.

Results
Clutch-size was not affected by location, orchard type, laying period or nest position. The number of chicks hatched per nest differed between orchard types; they were greater in olive orchards (1.33 ± 0.06) than in orange ones (1.03 ± 0.08), whereas the number of chicks fledged per nest consistently differed with laying period and orchard type, which were higher in the early laying period (1.22 ± 0.07) than in the late period (0.93 ± 0.08) and higher in olive orchards (1.22 ± 0.06) than in orange orchards (0.90 ± 0.06). Neither location nor nest position were related to variation in the fledging success of the Turtle Dove.

Conclusions
Olive orchards and the early laying period confer better nesting conditions than orange orchards and the late laying period. Although nest position could be different in each orchard type, it did not affect the breeding success of the Turtle Dove, suggesting that factors other than tree characteristics are influential. Further studies are needed to improve our understanding of the effects of anthropogenic disturbance, especially agricultural activities and hunting, on the productivity of Turtle Dove nests.

 

Turtle Doves: nest with two eggs, newly hatched chick, and adult at nest with its chicks

a) A nest of a Turtle Dove with two eggs on an olive tree. b) A nest of Turtle Dove with a newly hatched chick on an orange tree. c) A Turtle Dove at nest with its chicks on an orange tree (Saâd Hanane)

 

 

Food from dumps increases the reproductive value of last laid eggs in the White Stork Ciconia ciconia

Djerdali, S., Guerrero-Casado, J. & Tortosa, F. S. (2016). Food from dumps increases the reproductive value of last laid eggs in the White Stork Ciconia ciconia. Bird Study 63: 107–114.  doi: 10.1080/00063657.2015.1135305

Abstract:

Capsule: Accessing extra food from waste dumps increases egg volume and hatching mass in White Storks.

Aim: To test how White Storks vary their investment in egg size, especially in last laid eggs, in relation to food availability, and to improve our understanding of the importance of extra feeding on intra-clutch variation.

Methods: The study was carried out in three White Stork breeding colonies in northern Algeria. Breeding performance was recorded in 70 nests over three years. White Stork colonies situated close to chicken farms were considered to be part of a ‘pseudo experiment’ where parents had access to extra food. Egg volume, laying order, hatching order and hatching weight were recorded.

Results: Egg volume and hatching mass in White Storks was significantly greater when they had access to extra food. The reproductive value of last laid eggs (fourth and fifth) doubled when females had access to extra food.

Conclusion: Laying smaller last eggs within a clutch provides a mechanism to facilitate early brood reduction in the White Stork, and so should be advantageous when food is scarce. On the contrary, when females had access to extra food, last laid eggs were as big as first eggs which suggests egg size variation is adaptable to local conditions.

White Storks (Ciconia ciconia) at nest, Algeria

White Storks (Ciconia ciconia) at nest, Algeria (Ali Mehadji, flickr)

Costs of migratory decisions: A comparison across eight white stork populations

Flack, A., Fiedler, W., Blas, J., Pokrovsky, I., Kaatz, M., Mitropolsky, M., Aghababyan, K., Fakriadis, I., Makrigianni, E., Jerzak, L. and Azafzaf, H., Feltrup-Azafzaf, C., Rotics, S., Mokotjomela, T. M., Nathan, R. & Wikelski, M. 2016. Costs of migratory decisions: A comparison across eight white stork populations. Science Advances 2(1): p.e1500931. doi: 10.1126/sciadv.1500931 (Open Access)

Abstract:

Annual migratory movements can range from a few tens to thousands of kilometers, creating unique energetic requirements for each specific species and journey. Even within the same species, migration costs can vary largely because of flexible, opportunistic life history strategies. We uncover the large extent of variation in the lifetime migratory decisions of young white storks originating from eight populations. Not only did juvenile storks differ in their geographically distinct wintering locations, their diverse migration patterns also affected the amount of energy individuals invested for locomotion during the first months of their life. Overwintering in areas with higher human population reduced the stork’s overall energy expenditure because of shorter daily foraging trips, closer wintering grounds, or a complete suppression of migration. Because migrants can change ecological processes in several distinct communities simultaneously, understanding their life history decisions helps not only to protect migratory species but also to conserve stable ecosystems.

Migratory behavior of juveniles from eight different White Stork populations

Fig. 1. Migratory behavior of juveniles from eight different White Stork populations (Flack et al. 2016)