du Rau P.D.,CNERAavifaune migratrice |
Bourgeois K.,University of Auckland |
Bourgeois K.,Aix - Marseille University |
Thevenet M.,Conservatoire du littoral |
And 19 more authors.
Journal of Ornithology | Year: 2015
Scopoli’s Shearwater (Calonectris diomedea) is a Procellariiform endemic to the Mediterranean Basin which is considered to be vulnerable in Europe due to recent local declines and its susceptibility to both marine and terrestrial threats. In the 1970s–1980s, its population size was estimated at 57,000–76,000 breeding pairs throughout the Mediterranean Basin, with the largest colony, estimated at 15,000–25,000 pairs, found on Zembra Island, Tunisia. The objectives of our study were to re-estimate the size of the breeding population on Zembra Island, to reassess the global population size of the species, and to analyse the implications of these findings on status and conservation of this species in the Mediterranean. Using distance sampling, we estimated the Zembra breeding population to be 141,780 pairs (95 % confidence interval 113,720–176,750 pairs). A review of the most recent data on populations of this species throughout the Mediterranean Basin led us to estimate its new global population size at 141,000–223,000 breeding pairs. Using the demographic invariant and potential biological removal approaches, we estimated the maximum number of adults which could be killed annually by all non-natural causes without causing a population decline to be 8800 (range 7700–9700) individuals, of which could be 3700 breeders. Although these results are less alarming in the context of species conservation than previously thought, uncertainties associated with global population size, trends and major threats still raise questions on the future of this species. More generally, we show how a monitoring strategy for a bird supposed to be relatively well known overall can be potentially misleading due to biases in survey design. The reduction of such biases would therefore appear to be an unavoidable prerequisite in cryptic species monitoring before any reliable inference on the conservation status of the species can be drawn. © Dt. Ornithologen-Gesellschaft e.V. 2015
Azafaf H.,Ariana Center |
Feltrup-Azafzaf C.,Ariana Center |
Dlensi H.,Ariana Center |
Isenmann P.,CNRS Center of Evolutionary and Functional Ecology
Alauda | Year: 2015
After the comprehensive annotated checklist of the birds of Tunisia published in 2005, this report deals with records collected between 2005 and 2014. Ten (or perhaps twelve) new species for the country could be added (Lesser Flamingo, Eastern Imperial Eagle, Black-winged Pratincole, Spotted Sandpiper, White-rumped Sandpiper, Lesser Yellowlegs, Sabinés Gull, Rose-ringed Parakeet, Citrine Wagtail, Pallas's Leaf Warbler and presumably Royal Tern and African Reed Warbler). Four species were found breeding for the first time (Yelkouan Shearwater, Glossy Ibis, Black-headed Gull, Grey Wagtail) and the breeding of two others needs to be confirmed (Northern Goshawk, African Reed Warbler). Some rarely recorded species have been recorded again (Red-throated Diver, Red-necked Grebe, Yellow-billed Stork, Greater Scaup, Greater Spotted Eagle, American Golden Plover, Sociable Lapwing, Red Phalarope, Grey-hooded Gull, Caspian Gull, White-rumped Swift, Blue-cheeked Beeeater, Hooded Crow, Brambling). The Slender-billed Curlew having not been recorded in recent years must be considered as extinct.