23 research outputs found

    Analysis of pellets from a suburban Common Kestrel Falco tinnunculus nest in El Harrach, Algiers, Algeria

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    The diet of a Common Kestrel Falco tinnunculus in a suburban area of Algiers at El Harrach was determined by pellet analysis over two years. In both years, the hybrid sparrow (Passer domesticus x P. hispaniolensis) was the main prey item, based on relative frequency (22.3% and 58.7% in 1999 and 2000, respectively). Greenfinch Carduelis chloris was the next most important prey item in 1999 (14% of relative frequency), followed by Kuhl's Pipistrelle Pipistrellus kuhli (9.4%), striped earwigs Labidura riparia and rose chafers Potosia cuprea (7.9% each) and millipedes Polydesmus sp., which contributed 5.8% of the relative proportion. In 2000, the other prey species in the diet made up less than 5% of the proportion. In terms of biomass, the hybrid sparrow was the main prey represented, with 47.6% in 1999 and 78.7% in 2000, followed by Carduelis chloris, with 29.8% of biomass, and ocellated skink Chalcides ocellatus, with 10.2% of biomass in 1999. In 2000, the other prey species made up less than 10% of the biomass. As with other urban studies in Europe, birds make up an important component of the kestrel's diet. Ostrich 2006, 77(3&4): 175–17

    New African Lower Carboniferous paleomagnetic pole from intrusive rocks of the Tin Serririne basin (Southern border of the Hoggar, Algeria)

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    International audienceA paleomagnetic study has been conducted on intrusive doleritic rocks cropping out within Devonian horizontal tabular formations of the Saharan craton (Tin Serririne basin, South of Hoggar shield). The 40K/40Ar dating of the dolerites gave an age of 347.6 ± 8.1 Ma, i.e. Tournaisian. The paleomagnetic data present three different directions. The first has a paleomagnetic pole close to the previous African poles of Permian age. This direction is therefore interpreted as a Permian remagnetization. The second direction, which is defined by both linear regression and remagnetization circles analysis, is considered as the primary magnetization. It yields a new African Tournaisian paleomagnetic pole (λ = 18.8° S, phi = 31.2° E, K = 29, A95 = 7.5°) very close to the Ben Zireg Tounaisian pole [Aifa, T., Feinberg, H., Pozzi, J.P., 1990. Devonian/Carboniferous paleopoles for Africa. Consequences for Hercynian geodynamics. Tectonophysics, 179, 288–304]. The third direction has intermediate orientation between those of the first or second directions and that of the Upper Cenozoic field. It is interpreted as related to a composite magnetization. This new Tin Serririne pole improves the APWP of Gondwana, for this key period of the evolution of the Pangea. This APWP confirms the previous paleogeographic reconstruction which shows that the pre-Hercynian ocean between Gondwana and Laurussia is still not close during the beginning of the Carboniferous
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