Breeding ecology of colonial White Storks (Ciconia ciconia) in northeast Algeria

Bouriach, M., Samraoui, F., Souilah, R., Houma, I., Razkallah, I., Alfarhan, A. H. & Samraoui, B. (2015). Does core-periphery gradient determine breeding performance in a breeding colony of White Storks Ciconia ciconia? Acta Ornithologica 50: 149–156. doi: 10.3161/00016454AO2015.50.2.003
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Abstract:

The timing of breeding and nest location in colonial birds may have fitness consequences. In particular, it has been demonstrated that peripheral breeders perform less well than core breeders. To determine whether environmental factors such as date of breeding and nest position influence reproductive success, we studied the breeding ecology of a large colony of White Stork Ciconia ciconia at Dréan, northeast Algeria, during 2011 and 2012. Mean egg-laying dates varied significantly between years and differed between core and peripheral nests with more precocious laying occurring in the center. Egg-laying in larger nests started earlier than in smaller ones in the core area but neither nest size nor nest position along the core-periphery gradient had any influence on studied breeding parameters i.e. clutch size, hatching success and chick productivity. There was no yearly difference in clutch size which averaged 4.7 ± 0.7 eggs (N = 156 clutches). Mean chick productivity was higher in 2012 (2.85 ± 1.21 chicks) than in 2011 (2.29 ± 2.28 chicks) and was marginally associated with egg-laying date. In contrast, nesting success declined with delayed onset of breeding. Results suggest that a low predation rate, abundant resources and a possible trade-off between fitness components may confound adaptive breeding-habitat selection in White Stork.

Young White Storks (Ciconia ciconia) at nest

Young White Storks (Ciconia ciconia) at nest (Frans de Wit, CC-by-nc-nd license)

Factors affecting nesting success in the Great-crested Grebe Podiceps cristatus at Lake Tonga, north-east Algeria

Cheriet, S., Samraoui, F., Alfarhan, A. H. & Samraoui, B. (2015). Factors affecting nesting success in the Great-crested Grebe Podiceps cristatus at Lake Tonga, north-east Algeria. Ostrich 86(3): 239-245.      doi: 10.2989/00306525.2015.1067932
PDF in ResearchGate.net

Abstract:

The breeding ecology of the Great-crested Grebe Podiceps cristatus was investigated over four consecutive years (2009-2012) at Lake Tonga, north-east Algeria. In all four years, the egg-laying period was relatively short, spanning two months (end of March to end of May), and bimodal. Nests were mainly located in Phragmites australis, over water of substantial depth (178 ± 43 cm, N=209), far from the shore and in habitat with low vegetation cover (12.37 ± 7.67%, N=209). The overall clutch size was 3.73 ± 0.92 eggs (N=127) and it decreased marginally over time. The overall nesting success was 70.4% (N=209), with nest failure caused mainly by predation (65%) and flooding (23%). Breeding outcome was significantly and positively related to nest size, with bigger nests conferring better survival to eggs and young probably through affording better protection during spells of adverse weather. However, the benefits of bigger nests may be confounded by the age or intrinsic quality of birds. The location of nests in P. australis, rather than other vegetation types, increased nesting success marginally but significantly. Two cases of interspecific mixed clutches involving the Great-crested Grebe were recorded.

Great-crested Grebe (Podiceps cristatus) and chicks

Great-crested Grebe (Podiceps cristatus) and chicks (Michael Brace, flickr)