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Wojciechowski M.S.,Nicolaus Copernicus University | Yosef R.,International Birding and Research Center in Eilat
Journal of Ethology | Year: 2011

We designed a field experiment on breeding house martins (Delichon urbica) which build conspicuous nests in human structures, which require the parents to be wary of potential predators. Some birds therefore avoid entering the nest in the presence of a potential nest predator when the parent is most vulnerable when inside the nest. Therefore, the hesitation to enter the nest in the presence of a potential predator might be for the bird's own safety. A number of species show such a hesitation in response to a human observer. Using this behaviour exhibited by the house martin, we show here that the bird appreciates the perspective of the observer and behaves as if it can understand what the observer 'knows'. © 2010 Japan Ethological Society and Springer.

Zduniak P.,Adam Mickiewicz University | Yosef R.,International Birding and Research Center in Eilat | Sparks T.H.,University of Life Sciences in Poznań | Smit H.,International Birding and Research Center in Eilat | Tryjanowski P.,University of Life Sciences in Poznań
Climate Research | Year: 2010

We examined phenological change in the spring migratory passage of the predatory steppe eagle Aquila nipalensis from 1977 to 2008. Data were collected at Eilat, Israel, a globally important site for migrating raptors. Changes in the observation dates of spring passage migration were examined using correlation and regression analyses to assess changes over time as well as potential relationships with temperature and with the Indian Ocean Dipole, an index of climate in the wintering area. Over the study period, the number of recorded steppe eagles decreased significantly, as did the proportion of juveniles. Despite the population decrease there was a rapid advance in first spring passage date. Although changes in passage dates were related to environmental conditions in wintering and en-route areas, we suggest that one possible additional reason for such a rapid advance is due to increasing competition between individuals for breeding territories due to dwindling habitats. In addition, changes to some aspects of the passage distribution may be a consequence of a changing age structure. © Inter-Research 2010.

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.

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.

Keynan O.,Tel Aviv University | Yosef R.,International Birding and Research Center in Eilat
Behavioural Processes | Year: 2010

The Southern Grey Shrike (Lanius meridionalis) is a common resident along the rift valley. During 2007-2008 we studied the impaling behavior of Southern Grey Shrikes at the Shezaf nature reserve by food supplementation. Our findings indicate seasonal shifts in impaling behavior. During the winter, there was no difference between the sexes and shrikes impaled house mice (Mus musculus) close to their territorial boundaries with neighboring conspecifics. All impaled mice disappeared from the tree within a few hours of impalement. During the mating season, males impaled the whole prey and let females eat it, and prey was impaled by both sexes only in order to dismember and feed the nestlings. Shrikes impaled and cached meal worms only after they were satiated. The number of meal worms taken to be hoarded increased during the non-breeding season, but during the breeding season male shrikes preferred to feed the females. During the entire research period we did not find any specific cache sites or trees and no prey remained impaled for extended periods of time. In conclusion, impaling prey changed temporally and between sexes: from being a signal for conspecifics to pair bonding. © 2010 Elsevier B.V.

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.

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.

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.

Zduniak P.,Adam Mickiewicz University | Yosef R.,International Birding and Research Center in Eilat
Ornis Fennica | Year: 2011

We studied the migration patterns of Red-throated (Anthus cervinus) and Tree Pipits (A. trivialis) ringed during 25 years at Eilat, Israel. The number of migrants was four times greater in spring than in autumn for the Tree Pipit but was similar for the Red-throated Pipit. Stop-over during the migration seasons was also different. Both young and old Redthroated Pipits used Eilat as a stop-over site at similar intensity during both seasons. However, most of the Tree Pipits in autumn were juveniles, but young and old individuals were almost equally abundant in spring. In both species, body-condition index was higher in autumn than in spring and was not related to the age of the birds. This finding illustrates differences in body condition before and after the crossing of the Saharo-Arabian desert belt.

Yosef R.,International Birding and Research Center in Eilat | Zduniak P.,Adam Mickiewicz University
Acta Ethologica | Year: 2011

Sandgrouse (Pterocles spp.) are adapted to extreme desert environments. One such adaptation is that males transport water in their abdominal feathers to water the nesting female and hatchlings. Hence, understanding sandgrouse drinking regime and regularly used water holes is of great conservation importance. We studied the arrival of four sandgrouse species at a single water hole in the western Negev Desert, Israel. During our visits, the most numerous species was the Spotted Sandgrouse, and in decreasing abundance, we found Black-bellied Sandgrouse, Crowned Sandgrouse, and Pin-tailed Sandgrouse. Black-bellied Sandgrouse arrived significantly earlier than Spotted Sandgrouse and Crowned Sandgrouse. Spotted Sandgrouse arrival peaked later in the morning than Black-bellied Sandgrouse and Crowned Sandgrouse. The data suggest that this is connected to the absolute number of birds for each of the species which influences their synchronous arrival. Also, we find that the amount of time a species spends at the water hole is influenced by the number of birds present, i. e., the species that stay the longest are also the most numerous. The mean temperature when Spotted Sandgrouse peaked was marginally higher (21.2°C) than recorded for Black-bellied (19.5°C) and Crowned Sandgrouse (19.3°C). © 2010 Springer-Verlag and ISPA.

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