The combined actions of climatic variations and landscape barriers shape the history of natural p... more The combined actions of climatic variations and landscape barriers shape the history of natural populations. When organisms follow their shifting niches, obstacles in the landscape can lead to the splitting of populations, on which evolution will then act independently. When two such populations are reunited, secondary contact occurs in a broad range of admixture patterns, from narrow hybrid zones to the complete dissolution of lineages. A previous study suggested that barn owls colonized the Western Palearctic after the last glaciation in a ring-like fashion around the Mediterranean Sea, and conjectured an admixture zone in the Balkans. Here, we take advantage of whole-genome sequences of 94 individuals across the Western Palearctic to reveal the complex history of the species in the region using observational and modeling approaches. Even though our results confirm that two distinct lineages colonized the region, one in Europe and one in the Levant, they suggest that it predates t...
Islands, and the particular organisms that populate them, have long fascinated biologists. Due to... more Islands, and the particular organisms that populate them, have long fascinated biologists. Due to their isolation, islands offer unique opportunities to study the effect of neutral and adaptive mechanisms in determining genomic and phenotypical divergence. In the Canary Islands, an archipelago rich in endemics, the barn owl (Tyto alba) is thought to have diverged into a subspecies (T. a. gracilirostris) on the eastern islands, Fuerteventura and Lanzarote. Taking advantage of 40 whole-genomes and modern population genomics tools, we provide the first look at the origin and genetic makeup of barn owls of this archipelago. We show that the Canaries hold diverse, long-standing and monophyletic populations with a neat distinction of gene pools from the different islands. Using new method, less sensitive to structure than classicalFST, to detect regions involved in local adaptation to the insular environment, we identified a haplotype-like region likely under positive selection in all Can...
Climate change affects timing of reproduction in many bird species, but few studies have investig... more Climate change affects timing of reproduction in many bird species, but few studies have investigated its influence on annual reproductive output. Here, we assess changes in the annual production of young by female breeders in 201 populations of 104 bird species (N = 745,962 clutches) covering all continents between 1970 and 2019. Overall, average offspring production has declined in recent decades, but considerable differences were found among species and populations. A total of 56.7% of populations showed a declining trend in offspring production (significant in 17.4%), whereas 43.3% exhibited an increase (significant in 10.4%). The results show that climatic changes affect offspring production through compounded effects on ecological and life history traits of species. Migratory and larger-bodied species experienced reduced offspring production with increasing temperatures during the chick-rearing period, whereas smaller-bodied, sedentary species tended to produce more offspring....
Rodent pests cause extensive damage to agricultural crops worldwide. Farmers’ ability to monitor ... more Rodent pests cause extensive damage to agricultural crops worldwide. Farmers’ ability to monitor rodent activity and damage within crops is limited due to their inability to simultaneously survey vast agricultural areas for rodent activity, the inability to enter certain fields, and the difficulty of monitoring rodent numbers, as well as using traps due to trap shyness and high labor costs. Drones can potentially be used to monitor rodent numbers and damage because they can cover large areas quickly without damaging crops and carry sensors that provide high-resolution imagery. Here, we investigated whether rodent activity (Levant voles Microtus guentheri and house mice Mus musculus) is related to vegetation health and biomass in Alfalfa (Medicago sativa) fields. We used a drone to photograph one hundred and twenty 10 × 10 m plots in nine fields and calculate the plots’ normalized difference vegetation index (NDVI) and biomass. On each plot, we also trapped rodents, counted rodent bu...
Many nocturnal avian species, such as Strigiformes, Caprimulgiformes and Apterygiformes, have sen... more Many nocturnal avian species, such as Strigiformes, Caprimulgiformes and Apterygiformes, have sensitive vibrotactile bristles on their upper bill, especially on their rictus. The anatomy of these bristles can vary, especially in terms of sensitivity (Herbst corpuscle number), bristle length and bristle number. This variation is thought to be associated with foraging - such that diurnal, open foragers have smaller and less-sensitive bristles. Here, we describe bristle morphology and follicle anatomy in the western barn owl (Tyto alba) for the first time, using both live and roadkill wild owls. We show that T. alba have both narial and rictal bristles that are likely to be vibrotactile, since they have Herbst corpuscles around their follicles. We observed more numerous (~8) and longer bristles (~16 mm) on the nares of T. alba, than on the rictal region (~4 and ~13 mm respectively). However, the narial bristle follicles contained fewer Herbst corpuscles in their surroundings (~5) than the rictal bristles (~7); indicating that bristle length is not indicative of sensitivity. As well as bristle length and number varying between different facial regions, they also varied between individuals, although the cause of this variation remains unclear. Despite this variation, the gross anatomy of facial bristle follicles appears to be conserved between nocturnal Strigiformes, Caprimulgiformes and Apterygiformes. Understanding more about how T. alba use their bristles would, therefore, give us greater insights into the function of avian bristles in general.
P. Gonzalez, T. Lizee, L. Gehring, M. Charter, K. Witzke, FACSM Oregon State University - Cascade... more P. Gonzalez, T. Lizee, L. Gehring, M. Charter, K. Witzke, FACSM Oregon State University - Cascades, Bend, OR Whole-body high-intensity interval training (HIIT) has gained wide popularity in the fitness industry. Research suggests that HIIT benefits can be achieved in less time compared with steady state, moderate-intensity exercise. Published studies using HIIT, however, focus primarily on bicycle ergometer or treadmill-based exercises, with very limited research on the effects of functional exercise such as that used during whole-body HIIT, on heart rate and post-exercise oxygen consumption (EPOC). PURPOSE: To compare the exercise heart rate (HR), respiratory exchange ratio (RER), VO2 and EPOC following a 10-minute whole-body HIIT workout and a 20-minute steady-state, moderate-intensity workout. METHODS: Seven low-risk subjects (6 females and 1 male) aged 33.4±7.2y, who participated in whole-body HIIT a minimum of 3 d/wk for 6 months provided consent for the study. On day one, subjects performed a 20-minute rowing ergometer exercise at an intensity of +5 bpm of 70% age-predicted max HR. On a separate day, they performed a 10-minute whole-body HIIT workout consisting of as many continuous reps as possible of 10 barbell thrusters (men 75lbs/women 55 lbs) and 10 burpees over the barbell. Heart rate, VO2, RER and EPOC were measured using indirect calorimetry immediately following each exercise and throughout recovery until VO2 and RER returned to pre-workout levels. Heart rate was continuously monitored during the workouts and throughout recovery. Differences in time to recovery for VO2 and RER were determined using dependent t-tests (p\u3c0.05). RESULTS: Subjects achieved 97.3+3.7% of their predicted max HR during the whole-body HIIT workout, classifying it as a maximal-effort exercise. A significant difference was found in the time to return to resting RER values between the two workouts (16.7+4.0 min after the row vs. 29.2+9.7 min after whole-body HIIT, p\u3c0.01). Peak VO2 levels immediately after exercise differed between workouts (19.5+4.8 ml/kg/min after rowing vs. 32.9+6.0 ml/kg/min after whole-body HIIT, p\u3c0.001), as did the time for VO2 recovery (13.25+8.5 min after rowing vs. 25.5+14.75 min after whole-body HIIT, p\u3c0.05). CONCLUSION: There was a significant 12.5 and 12.25 min longer recovery time for RER and VO2, respectively, following whole-body HIIT. This was likely due to a longer time to restore ATP-PC and O2 stores, remove lactate, and restore cardiovascular and respiratory function following whole-body HIIT. Heart rate never returned to baseline during recovery following whole-body HIIT. Longer recovery times suggest a higher caloric expenditure following whole-body HIIT compared to moderate-intensity exercise, despite half the workout time
The biodiversity of native species is diminishing in many regions as natural habitats are being r... more The biodiversity of native species is diminishing in many regions as natural habitats are being replaced by human settlements and agriculture. Top predators, such as large raptors, are especially sensitive to habitat change, and they present flagship species due to the interest in them by the public. By protecting the raptors’ habitats we also protect other species that reside within these habitats. A large population of Short-toed Eagles ( Circaetus gallicus, hereafter StE) were studied in the Judea region of Israel across a 1,175 km2 study site during the 2006–2008 breeding seasons, in order to determine whether the different types of habitat affect the number of successful breeding pairs. During the three-year study, we recorded 288 breeding attempts by StE pairs in 156 different nests located mainly on trees. Of the successful StE pairs, 76.9% bred in natural habitats while fewer pairs than expected bred in agricultural areas and human settlements. The mean number of successful ...
Patients undergoing elective surgery for removal of brain tumors, aneurysms, or other vascular ma... more Patients undergoing elective surgery for removal of brain tumors, aneurysms, or other vascular malformations were administered a single oral dose of sparfloxacin (400 mg; 16 patients) or ciprofloxacin (750 mg; 5 patients) either 3 to 5 h or 22 to 26 h before surgery. Serum samples were taken from all patients at 0, 1, 3 to 5, 7 to 9, and 22 to 26 h after dosing; an additional serum sample was obtained at 48 h from patients who received sparfloxacin. A single sample of brain tissue was taken from all patients; a sample of cerebrospinal fluid (CSF) uncontaminated with blood was obtained from five patients. Serum and brain tissue samples were assayed by high-pressure liquid chromatography. Drug concentrations in brain tissue exceeded those in CSF by 1.8- to 19.4-fold. Kinetic modeling suggested that peak sparfloxacin concentrations in brain tissue may have occurred later than 3 to 5 h and that actual peak concentrations may therefore have been higher (up to 10 micrograms/g of tissue). ...
Preserving ecosystem services, such as natural enemies that can provide pest control, can positiv... more Preserving ecosystem services, such as natural enemies that can provide pest control, can positively impact crops without compromising agricultural yield. Even though controlling pests by natural enemies has been suggested to reduce pests in agriculture, growers continue using conventional pesticides that kill beneficial predators. Here we studied whether the predation of avian and insect-beneficial predators varies in an apple orchard with conventional insecticide use compared to a bordering tree stand without insecticides. We studied the predation rates of mealworm pupae as a proxy to coddling moth pupae at 42 stations in both an apple orchard and a Eucalyptus stand at three distances (0 m, 50 m, and 100 m) from the border. Half of the stations were netted to prevent bird predation but were accessible to insects. The other half were non-netted and accessible to birds. We conducted six trials, each lasting two weeks, during which we recorded the predation of 504 stations with 5040 ...
Even though birds are some of the most common road-killed animals, it remains to be determined wh... more Even though birds are some of the most common road-killed animals, it remains to be determined whether avian roadkills are related to breeding numbers and breeding success, mainly due to a lack of study areas that monitor breeding populations and roadkills. We studied whether barn owl breeding numbers and breeding success are related to roadkills. We monitored yearly barn owl breeding numbers (2174 breeding attempts and 1682 adults ringed) and breeding success (9380 nestlings ringed) and monitored 95 km of roads weekly for roadkills from 2009 to 2017 in the Beit Shean and Emek Yizreel Valleys, Israel. During the study period, we documented 1073 road-killed barn owls, of which 328 were ring recoveries. The highest mortality occurred between July to September, coinciding with the barn owl post-fledging period. The number of breeding pairs and the number of nestlings ringed were positively related to the total number of barn owl roadkill, the proportion of roadkill ring recoveries, and...
Fledgling birds sometimes abandon their own nest and move to neighboring nests where they are fed... more Fledgling birds sometimes abandon their own nest and move to neighboring nests where they are fed by host parents. This behaviour, referred to as “nest‐switching”, is well known in precocial birds that are mobile soon after hatching and can easily reach foster nests. In contrast, due to the difficulty of observing nest‐switching in territorial altricial birds, the causes and consequences of moving to others’ nests are poorly known in this group of birds. Nest‐switchers can be adopted by the foster parents or they can steal food from the host parents meant for their offspring, a form of kleptoparasitism, which may result in reduced breeding success of the host nest. In Israel, 12 barn owl fledglings left their natal nests and were found in 9 host nests out of 111 monitored nests (8.1%). Nest‐switchers that fledged earlier in the breeding season flew shorter distances to reach host nests probably because the density of nests with younger nestlings is higher early in the season. The number of host nestlings fledged and the percentage of nestlings fledged was lower in host nests than in nest without switchers. The occasional nest‐switchers were always older than host nestlings (respectively 80 and 50 days of age, on average) and host parents fledged fewer young when nest‐switchers occupied host nests with younger nestlings. This suggests that nest‐switchers are kleptoparasites because the presence of the older alien fledglings is associated with a lower breeding success of the host parents
The Barn Owl is one of the most widespread (Burton 1984) and researched owls in the world, but in... more The Barn Owl is one of the most widespread (Burton 1984) and researched owls in the world, but information on its breeding success in the Middle East is limited (Kahila 1992). Barn Owls are obligate cavity nesters that nest in a wide variety of natural cavities such as in holes in trees and caves (Taylor 1994) and in abandoned Hamerkop Scopus umbretta nests in Africa (Wilson et al 1986, Fry et al 1988). There is also a long history of Barn Owls using buildings and other manmade structures as nest sites; eg in roofs of houses, towers and castles, on silos, water tanks, in barns, even in wells and of course in nest boxes (de Bruijn 1984, Petty et al 1994, Taylor 1994). The Barn Owl is one of the commonest owls in Israel (Shirihai 1996) but little information has been published of basic biology other than dietrelated aspects (Dor 1982, Kahila 1992, Pokines & Peterhans 1997, YomTov & Wool 1997, Tores & YomTov 2003, Tores et al 2005, Charter et al 2007), although data are available on br...
The combined actions of climatic variations and landscape barriers shape the history of natural p... more The combined actions of climatic variations and landscape barriers shape the history of natural populations. When organisms follow their shifting niches, obstacles in the landscape can lead to the splitting of populations, on which evolution will then act independently. When two such populations are reunited, secondary contact occurs in a broad range of admixture patterns, from narrow hybrid zones to the complete dissolution of lineages. A previous study suggested that barn owls colonized the Western Palearctic after the last glaciation in a ring-like fashion around the Mediterranean Sea, and conjectured an admixture zone in the Balkans. Here, we take advantage of whole-genome sequences of 94 individuals across the Western Palearctic to reveal the complex history of the species in the region using observational and modeling approaches. Even though our results confirm that two distinct lineages colonized the region, one in Europe and one in the Levant, they suggest that it predates t...
Islands, and the particular organisms that populate them, have long fascinated biologists. Due to... more Islands, and the particular organisms that populate them, have long fascinated biologists. Due to their isolation, islands offer unique opportunities to study the effect of neutral and adaptive mechanisms in determining genomic and phenotypical divergence. In the Canary Islands, an archipelago rich in endemics, the barn owl (Tyto alba) is thought to have diverged into a subspecies (T. a. gracilirostris) on the eastern islands, Fuerteventura and Lanzarote. Taking advantage of 40 whole-genomes and modern population genomics tools, we provide the first look at the origin and genetic makeup of barn owls of this archipelago. We show that the Canaries hold diverse, long-standing and monophyletic populations with a neat distinction of gene pools from the different islands. Using new method, less sensitive to structure than classicalFST, to detect regions involved in local adaptation to the insular environment, we identified a haplotype-like region likely under positive selection in all Can...
Climate change affects timing of reproduction in many bird species, but few studies have investig... more Climate change affects timing of reproduction in many bird species, but few studies have investigated its influence on annual reproductive output. Here, we assess changes in the annual production of young by female breeders in 201 populations of 104 bird species (N = 745,962 clutches) covering all continents between 1970 and 2019. Overall, average offspring production has declined in recent decades, but considerable differences were found among species and populations. A total of 56.7% of populations showed a declining trend in offspring production (significant in 17.4%), whereas 43.3% exhibited an increase (significant in 10.4%). The results show that climatic changes affect offspring production through compounded effects on ecological and life history traits of species. Migratory and larger-bodied species experienced reduced offspring production with increasing temperatures during the chick-rearing period, whereas smaller-bodied, sedentary species tended to produce more offspring....
Rodent pests cause extensive damage to agricultural crops worldwide. Farmers’ ability to monitor ... more Rodent pests cause extensive damage to agricultural crops worldwide. Farmers’ ability to monitor rodent activity and damage within crops is limited due to their inability to simultaneously survey vast agricultural areas for rodent activity, the inability to enter certain fields, and the difficulty of monitoring rodent numbers, as well as using traps due to trap shyness and high labor costs. Drones can potentially be used to monitor rodent numbers and damage because they can cover large areas quickly without damaging crops and carry sensors that provide high-resolution imagery. Here, we investigated whether rodent activity (Levant voles Microtus guentheri and house mice Mus musculus) is related to vegetation health and biomass in Alfalfa (Medicago sativa) fields. We used a drone to photograph one hundred and twenty 10 × 10 m plots in nine fields and calculate the plots’ normalized difference vegetation index (NDVI) and biomass. On each plot, we also trapped rodents, counted rodent bu...
Many nocturnal avian species, such as Strigiformes, Caprimulgiformes and Apterygiformes, have sen... more Many nocturnal avian species, such as Strigiformes, Caprimulgiformes and Apterygiformes, have sensitive vibrotactile bristles on their upper bill, especially on their rictus. The anatomy of these bristles can vary, especially in terms of sensitivity (Herbst corpuscle number), bristle length and bristle number. This variation is thought to be associated with foraging - such that diurnal, open foragers have smaller and less-sensitive bristles. Here, we describe bristle morphology and follicle anatomy in the western barn owl (Tyto alba) for the first time, using both live and roadkill wild owls. We show that T. alba have both narial and rictal bristles that are likely to be vibrotactile, since they have Herbst corpuscles around their follicles. We observed more numerous (~8) and longer bristles (~16 mm) on the nares of T. alba, than on the rictal region (~4 and ~13 mm respectively). However, the narial bristle follicles contained fewer Herbst corpuscles in their surroundings (~5) than the rictal bristles (~7); indicating that bristle length is not indicative of sensitivity. As well as bristle length and number varying between different facial regions, they also varied between individuals, although the cause of this variation remains unclear. Despite this variation, the gross anatomy of facial bristle follicles appears to be conserved between nocturnal Strigiformes, Caprimulgiformes and Apterygiformes. Understanding more about how T. alba use their bristles would, therefore, give us greater insights into the function of avian bristles in general.
P. Gonzalez, T. Lizee, L. Gehring, M. Charter, K. Witzke, FACSM Oregon State University - Cascade... more P. Gonzalez, T. Lizee, L. Gehring, M. Charter, K. Witzke, FACSM Oregon State University - Cascades, Bend, OR Whole-body high-intensity interval training (HIIT) has gained wide popularity in the fitness industry. Research suggests that HIIT benefits can be achieved in less time compared with steady state, moderate-intensity exercise. Published studies using HIIT, however, focus primarily on bicycle ergometer or treadmill-based exercises, with very limited research on the effects of functional exercise such as that used during whole-body HIIT, on heart rate and post-exercise oxygen consumption (EPOC). PURPOSE: To compare the exercise heart rate (HR), respiratory exchange ratio (RER), VO2 and EPOC following a 10-minute whole-body HIIT workout and a 20-minute steady-state, moderate-intensity workout. METHODS: Seven low-risk subjects (6 females and 1 male) aged 33.4±7.2y, who participated in whole-body HIIT a minimum of 3 d/wk for 6 months provided consent for the study. On day one, subjects performed a 20-minute rowing ergometer exercise at an intensity of +5 bpm of 70% age-predicted max HR. On a separate day, they performed a 10-minute whole-body HIIT workout consisting of as many continuous reps as possible of 10 barbell thrusters (men 75lbs/women 55 lbs) and 10 burpees over the barbell. Heart rate, VO2, RER and EPOC were measured using indirect calorimetry immediately following each exercise and throughout recovery until VO2 and RER returned to pre-workout levels. Heart rate was continuously monitored during the workouts and throughout recovery. Differences in time to recovery for VO2 and RER were determined using dependent t-tests (p\u3c0.05). RESULTS: Subjects achieved 97.3+3.7% of their predicted max HR during the whole-body HIIT workout, classifying it as a maximal-effort exercise. A significant difference was found in the time to return to resting RER values between the two workouts (16.7+4.0 min after the row vs. 29.2+9.7 min after whole-body HIIT, p\u3c0.01). Peak VO2 levels immediately after exercise differed between workouts (19.5+4.8 ml/kg/min after rowing vs. 32.9+6.0 ml/kg/min after whole-body HIIT, p\u3c0.001), as did the time for VO2 recovery (13.25+8.5 min after rowing vs. 25.5+14.75 min after whole-body HIIT, p\u3c0.05). CONCLUSION: There was a significant 12.5 and 12.25 min longer recovery time for RER and VO2, respectively, following whole-body HIIT. This was likely due to a longer time to restore ATP-PC and O2 stores, remove lactate, and restore cardiovascular and respiratory function following whole-body HIIT. Heart rate never returned to baseline during recovery following whole-body HIIT. Longer recovery times suggest a higher caloric expenditure following whole-body HIIT compared to moderate-intensity exercise, despite half the workout time
The biodiversity of native species is diminishing in many regions as natural habitats are being r... more The biodiversity of native species is diminishing in many regions as natural habitats are being replaced by human settlements and agriculture. Top predators, such as large raptors, are especially sensitive to habitat change, and they present flagship species due to the interest in them by the public. By protecting the raptors’ habitats we also protect other species that reside within these habitats. A large population of Short-toed Eagles ( Circaetus gallicus, hereafter StE) were studied in the Judea region of Israel across a 1,175 km2 study site during the 2006–2008 breeding seasons, in order to determine whether the different types of habitat affect the number of successful breeding pairs. During the three-year study, we recorded 288 breeding attempts by StE pairs in 156 different nests located mainly on trees. Of the successful StE pairs, 76.9% bred in natural habitats while fewer pairs than expected bred in agricultural areas and human settlements. The mean number of successful ...
Patients undergoing elective surgery for removal of brain tumors, aneurysms, or other vascular ma... more Patients undergoing elective surgery for removal of brain tumors, aneurysms, or other vascular malformations were administered a single oral dose of sparfloxacin (400 mg; 16 patients) or ciprofloxacin (750 mg; 5 patients) either 3 to 5 h or 22 to 26 h before surgery. Serum samples were taken from all patients at 0, 1, 3 to 5, 7 to 9, and 22 to 26 h after dosing; an additional serum sample was obtained at 48 h from patients who received sparfloxacin. A single sample of brain tissue was taken from all patients; a sample of cerebrospinal fluid (CSF) uncontaminated with blood was obtained from five patients. Serum and brain tissue samples were assayed by high-pressure liquid chromatography. Drug concentrations in brain tissue exceeded those in CSF by 1.8- to 19.4-fold. Kinetic modeling suggested that peak sparfloxacin concentrations in brain tissue may have occurred later than 3 to 5 h and that actual peak concentrations may therefore have been higher (up to 10 micrograms/g of tissue). ...
Preserving ecosystem services, such as natural enemies that can provide pest control, can positiv... more Preserving ecosystem services, such as natural enemies that can provide pest control, can positively impact crops without compromising agricultural yield. Even though controlling pests by natural enemies has been suggested to reduce pests in agriculture, growers continue using conventional pesticides that kill beneficial predators. Here we studied whether the predation of avian and insect-beneficial predators varies in an apple orchard with conventional insecticide use compared to a bordering tree stand without insecticides. We studied the predation rates of mealworm pupae as a proxy to coddling moth pupae at 42 stations in both an apple orchard and a Eucalyptus stand at three distances (0 m, 50 m, and 100 m) from the border. Half of the stations were netted to prevent bird predation but were accessible to insects. The other half were non-netted and accessible to birds. We conducted six trials, each lasting two weeks, during which we recorded the predation of 504 stations with 5040 ...
Even though birds are some of the most common road-killed animals, it remains to be determined wh... more Even though birds are some of the most common road-killed animals, it remains to be determined whether avian roadkills are related to breeding numbers and breeding success, mainly due to a lack of study areas that monitor breeding populations and roadkills. We studied whether barn owl breeding numbers and breeding success are related to roadkills. We monitored yearly barn owl breeding numbers (2174 breeding attempts and 1682 adults ringed) and breeding success (9380 nestlings ringed) and monitored 95 km of roads weekly for roadkills from 2009 to 2017 in the Beit Shean and Emek Yizreel Valleys, Israel. During the study period, we documented 1073 road-killed barn owls, of which 328 were ring recoveries. The highest mortality occurred between July to September, coinciding with the barn owl post-fledging period. The number of breeding pairs and the number of nestlings ringed were positively related to the total number of barn owl roadkill, the proportion of roadkill ring recoveries, and...
Fledgling birds sometimes abandon their own nest and move to neighboring nests where they are fed... more Fledgling birds sometimes abandon their own nest and move to neighboring nests where they are fed by host parents. This behaviour, referred to as “nest‐switching”, is well known in precocial birds that are mobile soon after hatching and can easily reach foster nests. In contrast, due to the difficulty of observing nest‐switching in territorial altricial birds, the causes and consequences of moving to others’ nests are poorly known in this group of birds. Nest‐switchers can be adopted by the foster parents or they can steal food from the host parents meant for their offspring, a form of kleptoparasitism, which may result in reduced breeding success of the host nest. In Israel, 12 barn owl fledglings left their natal nests and were found in 9 host nests out of 111 monitored nests (8.1%). Nest‐switchers that fledged earlier in the breeding season flew shorter distances to reach host nests probably because the density of nests with younger nestlings is higher early in the season. The number of host nestlings fledged and the percentage of nestlings fledged was lower in host nests than in nest without switchers. The occasional nest‐switchers were always older than host nestlings (respectively 80 and 50 days of age, on average) and host parents fledged fewer young when nest‐switchers occupied host nests with younger nestlings. This suggests that nest‐switchers are kleptoparasites because the presence of the older alien fledglings is associated with a lower breeding success of the host parents
The Barn Owl is one of the most widespread (Burton 1984) and researched owls in the world, but in... more The Barn Owl is one of the most widespread (Burton 1984) and researched owls in the world, but information on its breeding success in the Middle East is limited (Kahila 1992). Barn Owls are obligate cavity nesters that nest in a wide variety of natural cavities such as in holes in trees and caves (Taylor 1994) and in abandoned Hamerkop Scopus umbretta nests in Africa (Wilson et al 1986, Fry et al 1988). There is also a long history of Barn Owls using buildings and other manmade structures as nest sites; eg in roofs of houses, towers and castles, on silos, water tanks, in barns, even in wells and of course in nest boxes (de Bruijn 1984, Petty et al 1994, Taylor 1994). The Barn Owl is one of the commonest owls in Israel (Shirihai 1996) but little information has been published of basic biology other than dietrelated aspects (Dor 1982, Kahila 1992, Pokines & Peterhans 1997, YomTov & Wool 1997, Tores & YomTov 2003, Tores et al 2005, Charter et al 2007), although data are available on br...
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