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Yosef R.,International Birding and Research Center in Eilat
Wilson Journal of Ornithology | Year: 2010

Birds in hyper-arid environments have acute problems of energy and water balance, and thermoregulate both physiologically and behaviorally. I report on European Bee-eaters (Merops apiaster) engaged in a previously unreported thermoregulatory behavior of diving into the sea and in salt ponds with high levels of salinity. This behavior may also explain the previously reported, but unexplained, finding of bee-eaters inside a tiger shark (Galeocerdo cuvier) in the Red Sea. These observations should instigate future experiments on the subject of selective use of salt water for evaporative cooling and thermoregulatory behavior by desert birds. © 2010 by the Wilson Ornithological Society. Source


Yosef R.,International Birding and Research Center in Eilat | Wineman A.,Middlebury College
Journal of Arid Environments | Year: 2010

We studied the stopover ecology of Blackcaps in Eilat, Israel, at the northern edge of the Saharan desert crossing. We investigated the Blackcaps with regard to differential migration by sex or age class in spring and autumn, and the stopover site in spring and autumn were compared. Using data from 1984 to 2003, we studied stopover length and fat deposition patterns differentiated by sex. In spring, Blackcap females remained in Eilat significantly longer than males. This suggests that males maintain a migration strategy of time-minimization, while females place more importance on energy-maximization. This difference is probably due to upcoming reproductive roles at the breeding grounds. © 2009 Elsevier Ltd. All rights reserved. Source


Zduniak P.,Adam Mickiewicz University | Yosef R.,International Birding and Research Center in Eilat
Journal of Arid Environments | Year: 2012

The Lesser Whitethroat is a very common passerine species with two of the main populations breeding in Europe and in southwest Asia, both wintering in East Africa. These populations must therefore cross the Sahara-Arabian desert belt twice each year. Ring recoveries from northwestern Europe indicate the importance of the eastern Mediterranean flyway between breeding and wintering grounds for this species funneling through Israel. The aim of the study was to describe the staging patterns and phenology of migratory Lesser Whitethroat at the Eilat stopover site located on the threshold of the Sahara-Arabian desert. The number of individuals ringed in spring was on average as much as 25.2 times higher than in autumn passage. We did not find any significant differences in age ratios between passage seasons; however in both seasons adults were recorded earlier than juveniles. Furthermore, the body condition was better during autumn than spring. An analysis of Lesser Whitethroats recaptured during spring passage showed that Eilat is a suitable stopover site for both age classes, which displayed similar staging pattern. Recaptured birds were in better body condition than at first capture, and the improvement of body condition was positively connected with the length of stay at the stopover site. © 2011 Elsevier Ltd. Source


Keynan O.,Tel Aviv University | Yosef R.,International Birding and Research Center in Eilat
Wilson Journal of Ornithology | Year: 2010

We studied the breeding ecology of the Southern Grey Shrike (Lanius meridionalis) at the Shezaf Nature Reserve, Arava Valley, Israel, an extremely arid desert with mean annual rainfall of 30 mm. We color-banded 128 shrikes during 2007-2009. The breeding season lasted from late February until late June. We found 34 nests and a correlation between years with amount of precipitation and number of breeding pairs. Second broods after successful broods were found only in 2007 and were all unsuccessful. Most nests were in Acacia trees; pairs that nested in dry trees, lacking foliage, were more likely to fail. The average clutch size was 3.44; average number of nestlings was 1.95; and average number of nestlings that fledged was 1.24. These results are lower than other studies of the species, probably a result of the scarcity of food in the arid environment. Nest survival rate was higher during incubation than during rearing of nestlings (0.71vs. 0.62), and total nest survival was 44.5%. The arid Arava Valley influences breeding success of Southern Grey Shrikes, and the present severe drought could negatively influence persistence of the shrike population in the Arava Valley. © 2010 by the Wilson Ornithological Society. Source


Yosef R.,International Birding and Research Center in Eilat | Yosef N.,Tel Aviv University
Journal of Ethology | Year: 2010

We describe cooperative hunting by Brown-necked Raven (Corvus ruficollis) on Egyptian Mastigure (Uromastyx aegyptius) in the Arava Valley, Israel. At first, in all nine observed hunts, the ravens were observed to be in the vicinity and were seen simultaneously. The Mastigure was almost always at a distance from the burrow entrance and either foraging on the bushes or lying flattened on a bush sunning itself. The attack started when a circling pair of ravens flew in at high speed and landed on the entrance of the burrow, cutting off the escape route of the lizard. Following this maneuver, the other ravens attacked the lizard. The ravens pecked randomly at the most exposed part of the lizard, eventually causing its death. Only when the lizard was evidently dead did the two individuals that blocked the escape route join in the feeding ravens. © Japan Ethological Society and Springer 2009. Source

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