Overwintering areas can act as reservoirs for haemosporidians, and their blood-sucking vectors may easily survive and flourish in warm climates. The American Kestrel (Falco sparverius) is a small-sized raptor that includes both resident and migratory individuals that overwinter in agriculture areas of the Baja California peninsula, Mexico. We measured and collected blood samples from 54 individual kestrels captured in a fragmented habitat located within a matrix of agricultural and native scrub in the southern part of the peninsula during the autumn and winter of 2018–2019 and 2019–2020. We identified and quantified haemosporidians in blood smears of each individual. We used decision tree classification models of prevalence and intensities of haemosporidians to assess the importance of season, host body size, and environmental characteristics of the capture site (proximity to the nearest infected host, number of ponds used for irrigation, Normalized Difference Vegetation Index [NDVI], distance to the edge of the agricultural matrix, and distance to the nearest city). Overall prevalence was 42.6%, with an average intensity of 2.4 haemosporidian-infected cells per 2000 erythrocytes. Most haemosporidians (91.3%) were identified as Haemoproteus tinnunculi, and the rest as Plasmodium spp. The prevalence of haemosporidians increased with pond availability, the distance from the edge of the agricultural matrix, and the proximity of infected individuals. Parasite intensity increased with the availability of ponds, the distance to the edge of the agriculture matrix, and the NDVI. Spatial and temporal patterns of parasite prevalence and intensity illustrated local infection dynamics, suggesting a complex scenario of haemosporidian transmission in migratory and resident kestrels.
{"title":"FACTORS INFLUENCING PREVALENCE AND INTENSITY OF HAEMOSPORIDIAN INFECTION IN AMERICAN KESTRELS IN THE NONBREEDING SEASON ON THE BAJA CALIFORNIA PENINSULA, MEXICO","authors":"M. Frixione, R. Rodríguez-Estrella","doi":"10.3356/jrr-22-74","DOIUrl":"https://doi.org/10.3356/jrr-22-74","url":null,"abstract":"\u0000 Overwintering areas can act as reservoirs for haemosporidians, and their blood-sucking vectors may easily survive and flourish in warm climates. The American Kestrel (Falco sparverius) is a small-sized raptor that includes both resident and migratory individuals that overwinter in agriculture areas of the Baja California peninsula, Mexico. We measured and collected blood samples from 54 individual kestrels captured in a fragmented habitat located within a matrix of agricultural and native scrub in the southern part of the peninsula during the autumn and winter of 2018–2019 and 2019–2020. We identified and quantified haemosporidians in blood smears of each individual. We used decision tree classification models of prevalence and intensities of haemosporidians to assess the importance of season, host body size, and environmental characteristics of the capture site (proximity to the nearest infected host, number of ponds used for irrigation, Normalized Difference Vegetation Index [NDVI], distance to the edge of the agricultural matrix, and distance to the nearest city). Overall prevalence was 42.6%, with an average intensity of 2.4 haemosporidian-infected cells per 2000 erythrocytes. Most haemosporidians (91.3%) were identified as Haemoproteus tinnunculi, and the rest as Plasmodium spp. The prevalence of haemosporidians increased with pond availability, the distance from the edge of the agricultural matrix, and the proximity of infected individuals. Parasite intensity increased with the availability of ponds, the distance to the edge of the agriculture matrix, and the NDVI. Spatial and temporal patterns of parasite prevalence and intensity illustrated local infection dynamics, suggesting a complex scenario of haemosporidian transmission in migratory and resident kestrels.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42796953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
American Kestrel (Falco sparverius) populations are generally declining across the species' North American distribution but the population in the Southern High Plains region currently appears to be stable. Historical evidence suggests the region formerly had a low abundance of kestrels, and that their current numbers are due to landscape changes associated with European settlement. We conducted monthly surveys for American Kestrels across 2 yr to estimate seasonal densities and identify land cover associations in the Southern High Plains of Texas. We found an overall estimated density of 0.99 birds/km2 (95% CI = 0.406, 1.582) across the 2-yr period, with seasonal estimated densities highest in autumn and winter (0.92–2.53/km2), and lowest in spring (0.49–0.67/km2). Whereas other studies have found that temperature influenced detection of wintering kestrels, we found an interaction of drought conditions and snow most strongly influenced the number of kestrels in our study area. Kestrels largely used land cover types in proportion to availability but there was some evidence of seasonal shifts. Generally, they tended to avoid cotton fields and sometimes selected for areas with woodlots, abandoned or occupied houses, and barns, all of which likely provided nesting and roosting opportunities. Our study provides the first contemporary assessment of seasonal abundance and habitat associations of American Kestrels in the Southern High Plains, where their presence and abundance has been unintentionally facilitated by landscape changes following settlement. We provide a baseline for population monitoring and studies assessing response to additional landscape changes (e.g., development of wind energy facilities) and a changing climate.
{"title":"SEASONAL ABUNDANCE AND HABITAT ASSOCIATIONS OF AMERICAN KESTRELS ON THE SOUTHERN HIGH PLAINS OF TEXAS","authors":"Kristen Linner-Warren, B. Bibles, C. Boal","doi":"10.3356/jrr-22-22","DOIUrl":"https://doi.org/10.3356/jrr-22-22","url":null,"abstract":"\u0000 American Kestrel (Falco sparverius) populations are generally declining across the species' North American distribution but the population in the Southern High Plains region currently appears to be stable. Historical evidence suggests the region formerly had a low abundance of kestrels, and that their current numbers are due to landscape changes associated with European settlement. We conducted monthly surveys for American Kestrels across 2 yr to estimate seasonal densities and identify land cover associations in the Southern High Plains of Texas. We found an overall estimated density of 0.99 birds/km2 (95% CI = 0.406, 1.582) across the 2-yr period, with seasonal estimated densities highest in autumn and winter (0.92–2.53/km2), and lowest in spring (0.49–0.67/km2). Whereas other studies have found that temperature influenced detection of wintering kestrels, we found an interaction of drought conditions and snow most strongly influenced the number of kestrels in our study area. Kestrels largely used land cover types in proportion to availability but there was some evidence of seasonal shifts. Generally, they tended to avoid cotton fields and sometimes selected for areas with woodlots, abandoned or occupied houses, and barns, all of which likely provided nesting and roosting opportunities. Our study provides the first contemporary assessment of seasonal abundance and habitat associations of American Kestrels in the Southern High Plains, where their presence and abundance has been unintentionally facilitated by landscape changes following settlement. We provide a baseline for population monitoring and studies assessing response to additional landscape changes (e.g., development of wind energy facilities) and a changing climate.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48477869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We analyzed long-term datasets from nest box programs, Breeding Bird Surveys run by the US Geological Survey, Christmas Bird Counts run by the National Audubon Society, and counts from two key fall migration watch sites, Hawk Mountain Sanctuary and Cape May Hawkwatch. We found that populations of American Kestrels (Falco sparverius) in North America are generally still declining, albeit with some caveats. Some populations are actually increasing, while others are remaining stable. Overall, the magnitude of annual change appears to be decreasing slightly during recent years. To understand potential causes of the decline, we recommend the following courses of action in no particular order: (1) determine whether the increase in Cooper's Hawk (Accipiter cooperii) populations is restricting kestrel distributions by the mere presence of the larger raptor; (2) study the effects of habitat loss and/or degradation on the falcon's wintering range; (3) further investigate on a broader spatial scale whether within-season habitat alterations are creating ecological traps for breeding kestrels; (4) determine the importance of arthropods in the diet of kestrels, especially the long-term population trends and timing of emergence of grasshoppers in relation to kestrel breeding chronology; (5) discover whether rodenticides pose a serious risk to American Kestrels across North America; (6) learn more about possible effects, both direct and indirect, that the use of neonicotinoids may have on kestrels; and (7) continue ongoing studies of the effect of climate change on these birds.
{"title":"EVIDENCE OF CONTINUING DOWNWARD TRENDS IN AMERICAN KESTREL POPULATIONS AND RECOMMENDATIONS FOR RESEARCH INTO CAUSAL FACTORS","authors":"D. M. Bird, John A. Smallwood","doi":"10.3356/jrr-22-35","DOIUrl":"https://doi.org/10.3356/jrr-22-35","url":null,"abstract":"\u0000 We analyzed long-term datasets from nest box programs, Breeding Bird Surveys run by the US Geological Survey, Christmas Bird Counts run by the National Audubon Society, and counts from two key fall migration watch sites, Hawk Mountain Sanctuary and Cape May Hawkwatch. We found that populations of American Kestrels (Falco sparverius) in North America are generally still declining, albeit with some caveats. Some populations are actually increasing, while others are remaining stable. Overall, the magnitude of annual change appears to be decreasing slightly during recent years. To understand potential causes of the decline, we recommend the following courses of action in no particular order: (1) determine whether the increase in Cooper's Hawk (Accipiter cooperii) populations is restricting kestrel distributions by the mere presence of the larger raptor; (2) study the effects of habitat loss and/or degradation on the falcon's wintering range; (3) further investigate on a broader spatial scale whether within-season habitat alterations are creating ecological traps for breeding kestrels; (4) determine the importance of arthropods in the diet of kestrels, especially the long-term population trends and timing of emergence of grasshoppers in relation to kestrel breeding chronology; (5) discover whether rodenticides pose a serious risk to American Kestrels across North America; (6) learn more about possible effects, both direct and indirect, that the use of neonicotinoids may have on kestrels; and (7) continue ongoing studies of the effect of climate change on these birds.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49353209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Allison Cornell, M. Fowler, Courtney Zimmerman, Zainab Khaku, J. Therrien
Diet is an important component of life history that can vary with, and ultimately determine, individual variation in phenotypically plastic traits. American Kestrels (Falco sparverius) generally have low post-fledging survival rates, which suggests a need to better understand what ecological factors, such as diet, influence nestling maturity. The generalist diet of kestrels makes it unlikely that all nestlings in a population receive the same diet. We investigated how breeding phenology and nestling sex ratio interact with diet metrics (diet diversity, percentage of prey types, rate of prey biomass delivery) and relate to nestling maturity (mass, tarsus length, wing length, hematocrit, hemoglobin concentration). We hypothesized that: (1) phenology and nestling sex ratio would correlate with inter-nest diet variation; (2) diet metrics would be predictive of nestling development; and (3) the manipulation of food quantity through food supplementation would lead to nestlings with greater developmental maturity. We found that inter-nest variation in diet was correlated with breeding phenology and nestling sex ratio, independently. However, the variation in diet was unrelated to nestling maturity. In response to food supplementation, kestrel parents decreased their food-provisioning rate, indicating that food quantity regulates parental care. Male nestlings appeared to benefit from supplementation while females did not. Our data demonstrated high inter-brood variation in nestling diet, and suggested that diet variation interacts with sex to influence growth and development of nestlings, which could potentially be linked to population decline.
{"title":"THE ROLE OF FOOD QUANTITY AND PREY TYPE IN NESTLING DEVELOPMENT OF AMERICAN KESTRELS","authors":"Allison Cornell, M. Fowler, Courtney Zimmerman, Zainab Khaku, J. Therrien","doi":"10.3356/jrr-22-10","DOIUrl":"https://doi.org/10.3356/jrr-22-10","url":null,"abstract":"\u0000 Diet is an important component of life history that can vary with, and ultimately determine, individual variation in phenotypically plastic traits. American Kestrels (Falco sparverius) generally have low post-fledging survival rates, which suggests a need to better understand what ecological factors, such as diet, influence nestling maturity. The generalist diet of kestrels makes it unlikely that all nestlings in a population receive the same diet. We investigated how breeding phenology and nestling sex ratio interact with diet metrics (diet diversity, percentage of prey types, rate of prey biomass delivery) and relate to nestling maturity (mass, tarsus length, wing length, hematocrit, hemoglobin concentration). We hypothesized that: (1) phenology and nestling sex ratio would correlate with inter-nest diet variation; (2) diet metrics would be predictive of nestling development; and (3) the manipulation of food quantity through food supplementation would lead to nestlings with greater developmental maturity. We found that inter-nest variation in diet was correlated with breeding phenology and nestling sex ratio, independently. However, the variation in diet was unrelated to nestling maturity. In response to food supplementation, kestrel parents decreased their food-provisioning rate, indicating that food quantity regulates parental care. Male nestlings appeared to benefit from supplementation while females did not. Our data demonstrated high inter-brood variation in nestling diet, and suggested that diet variation interacts with sex to influence growth and development of nestlings, which could potentially be linked to population decline.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44340161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"KEVIN J. KRITZ 1959–2022","authors":"","doi":"10.3356/jrr-in-memoriam","DOIUrl":"https://doi.org/10.3356/jrr-in-memoriam","url":null,"abstract":"","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":"120 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88597408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
American Kestrel (Falco sparverius) populations have been declining in North America during recent decades and potential causes, including climate change, currently are under investigation. Many studies of migratory birds have demonstrated the effects of climate change, including changes in local weather conditions and the increase in extreme weather, but the relationship between local weather and kestrel ecology in the northeastern United States has received little attention. We examined the relationship of local weather conditions and kestrel breeding performance in northwestern New Jersey between 1996 and 2016. We also obtained temperature, rainfall, and snowfall data from weather stations within or adjacent to our study area. We did not detect significant changes in climate over the study period, but we did find significant associations between local weather conditions and kestrel breeding performance. Warmer temperatures during the breeding season were significantly correlated with earlier nesting, and early nesting had significant positive correlations with clutch size, hatching rate, nestling survival, and nesting success (raising at least one young to fledging). We did not detect a significant relationship between rainfall and nesting variables, but snowfall during autumn was strongly related to kestrel breeding performance the following year. Compared to years when there was no snowfall in our study area the preceding autumn, kestrels breeding in years following autumn snow had significantly smaller clutches, lower hatching rates, lower nestling survival rate, and lower nesting success. Kestrels in our region are partial migrants; first-year birds generally migrate to southern wintering grounds while older birds may remain in the region, presumably in response to local conditions. We suggest that substantial snow during autumn may drive a larger percentage of adults to migrate south, as indicated by the greater number of kestrels counted at representative autumn hawk watch sites during years with substantial autumn snow. Our study concludes that variations in local weather conditions throughout the year can affect the breeding performance of American Kestrels, whether or not they are associated with climate change.
{"title":"THE EFFECT OF LOCAL WEATHER CONDITIONS ON AMERICAN KESTREL (FALCO SPARVERIUS) REPRODUCTION","authors":"","doi":"10.3356/jrr-22-40","DOIUrl":"https://doi.org/10.3356/jrr-22-40","url":null,"abstract":"\u0000 American Kestrel (Falco sparverius) populations have been declining in North America during recent decades and potential causes, including climate change, currently are under investigation. Many studies of migratory birds have demonstrated the effects of climate change, including changes in local weather conditions and the increase in extreme weather, but the relationship between local weather and kestrel ecology in the northeastern United States has received little attention. We examined the relationship of local weather conditions and kestrel breeding performance in northwestern New Jersey between 1996 and 2016. We also obtained temperature, rainfall, and snowfall data from weather stations within or adjacent to our study area. We did not detect significant changes in climate over the study period, but we did find significant associations between local weather conditions and kestrel breeding performance. Warmer temperatures during the breeding season were significantly correlated with earlier nesting, and early nesting had significant positive correlations with clutch size, hatching rate, nestling survival, and nesting success (raising at least one young to fledging). We did not detect a significant relationship between rainfall and nesting variables, but snowfall during autumn was strongly related to kestrel breeding performance the following year. Compared to years when there was no snowfall in our study area the preceding autumn, kestrels breeding in years following autumn snow had significantly smaller clutches, lower hatching rates, lower nestling survival rate, and lower nesting success. Kestrels in our region are partial migrants; first-year birds generally migrate to southern wintering grounds while older birds may remain in the region, presumably in response to local conditions. We suggest that substantial snow during autumn may drive a larger percentage of adults to migrate south, as indicated by the greater number of kestrels counted at representative autumn hawk watch sites during years with substantial autumn snow. Our study concludes that variations in local weather conditions throughout the year can affect the breeding performance of American Kestrels, whether or not they are associated with climate change.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":"2 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77262383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT. The strategies that migratory raptors adopt during migration reveal their long-term adaptations to different environments along their migration routes and of their stopover sites. We recorded the daily departure time of Chinese Sparrowhawks (Accipiter soloensis) and Gray-faced Buzzards (Butastur indicus) during their southward migration in autumn 2019 at Kenting National Park, southern Taiwan, and 2020 in Yushan National Park, central Taiwan. At both watchsites, Gray-faced Buzzards started their migration journey about 1 hr earlier than Chinese Sparrowhawks. After adjusting for the local sunrise time, the first daily appearance time of Gray-faced Buzzards (–2.5 ± 9.3 min) was significantly earlier than that of Chinese Sparrowhawks (47.0 ± 29.3 min) by about 50 min at Kenting National Park. Though they initiated migration later in morning at montane stopover sites in Yushan National Park, the same trend was observed and with even greater difference, about 70 min. These results indicate that these two species migrate in different daily periods and suggest that Chinese Sparrowhawks might choose to exploit stronger thermal uplifts in September before leaving the island, as they started migration later in the morning. In contrast, Gray-faced Buzzards, a species more dependent on soaring-gliding flight, set off earlier in the day, probably to take advantage of stronger northeastern tailwinds that begin in October. We conclude that the prevailing monthly wind conditions, particularly influenced by the northeast monsoons, shape the different diurnal migration times of these two raptors migrating along the East-Asian Oceanic Flyway. RESUMEN.— Las estrategias que adoptan las rapaces migratorias durante la migración revelan sus adaptaciones a largo plazo a diferentes ambientes a lo largo de sus rutas migratorias y de sus sitios de parada. Registramos la hora de partida diaria de Accipiter soloensis y Butastur indicus durante su migración hacia el sur en el otoño de 2019 en el Parque Nacional Kenting, en el sur de Taiwán, y en 2020 en el Parque Nacional Yushan, en el centro de Taiwán. En ambos sitios de observación, B. indicus comenzó su migración aproximadamente 1 hora antes que A. soloensis. Después de ajustar por la hora local del amanecer, el primer horario diario de aparición de B. indicus (–2,5 ± 9,3 min) fue significativamente más temprano que el de A. soloensis (47,0 ± 29,3 min) por unos 50 min en Kenting. Aunque iniciaron la migración más tarde en la mañana en los sitios montanos de parada en Yushan, se observó la misma tendencia y con una diferencia aún mayor, alrededor de 70 min. Estos resultados indican que estas dos especies migran en diferentes períodos diarios y sugieren que A. soloensis podría optar por explotar corrientes térmicas ascendentes más fuertes en septiembre antes de abandonar la isla, ya que comenzó a migrar más tarde en la mañana. Por el contrario, B. indicus, una especie que depende más del vuelo planeado, partió más t
摘要迁徙猛禽在迁徙过程中采取的策略揭示了它们对迁徙路线和中途停留地不同环境的长期适应。本文分别于2019年秋季和2020年秋季在台湾南部垦丁国家公园和中部玉山国家公园对中华雀鹰(Accipiter soloensis)和灰面秃鹰(Butastur indicus)南迁期间的每日出发时间进行了记录。在两个观察点，灰面秃鹰比雀鹰早1小时左右开始迁徙。经当地日出时间调整后，垦丁国家公园灰面秃鹰日首次出现时间(-2.5±9.3 min)明显早于华雀鹰(47.0±29.3 min)约50 min。在玉山国家公园的高山中转点，雀鹰的迁徙开始时间较晚，但两者的迁徙趋势相同，差异更大，均在70分钟左右。这些结果表明，这两个物种的迁徙时间不同，表明雀鹰可能会选择在9月离开岛屿前利用更强的热升，因为它们的迁徙开始时间较晚。相比之下，灰脸秃鹰，一种更依赖于翱翔滑翔飞行的物种，在一天的早些时候出发，可能是为了利用10月开始的更强的东北顺风。我们的结论是，盛行的月风条件，特别是受东北季风的影响，塑造了这两种猛禽沿东亚海洋飞行路线的不同日迁徙时间。RESUMEN。-在不同的环境中采用不同的策略，在不同的环境中采用不同的策略，在不同的环境中采用不同的策略，在不同的环境中采用不同的策略，在不同的环境中采用不同的策略。1 . soloiter (soloiter) (soloiter (soloiter))与巴西梧桐(Butastur indicus durente) (migración)联合登记:1 . 2019年1 .垦丁国家公园，2 . Taiwán国家公园，2 . 2020年1 .玉山国家公园，1 . Taiwán国家中心。研究结果表明:(1)巴西梧桐(observación) comenzó su migración与巴西梧桐(soloensis)相近。在垦丁，温度变化的时间为(47.0±29.3 min)，温度变化的时间为(- 2,5±9.3 min)，温度变化的时间为(- 2,5±9.3 min)。Aunque iniciaron la migracion mas tarde en la明天在洛杉矶sitios montano de parada玉山,se observo堂吉诃德tendencia y初步diferencia aun市长alrededor 70分钟。且resultados糖苷,是dos especies migran en不同periodos diario y sugieren, a soloensis podria optar为什么explotar科连特斯termicas运道mas要塞en septiembre都低于abandonar风光秀丽,丫,comenzo migrar mas tarde en la明天。穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷穷结论:多数情况下，男性在亚洲地区占主导地位，特别是在亚洲地区的影响下，男性在亚洲地区的影响更大，女性在亚洲地区的影响更大，女性在亚洲的影响更大。[Traducción del equipo社论]
{"title":"Migratory Daily Departure Times of Chinese Sparrowhawks (Accipiter soloensis) and Gray-Faced Buzzards (Butastur indicus) in Taiwan","authors":"I-Chen Wu, Yu-Jung Cheng, H. Lai, Chao-Chieh Chen","doi":"10.3356/JRR-22-64","DOIUrl":"https://doi.org/10.3356/JRR-22-64","url":null,"abstract":"ABSTRACT. The strategies that migratory raptors adopt during migration reveal their long-term adaptations to different environments along their migration routes and of their stopover sites. We recorded the daily departure time of Chinese Sparrowhawks (Accipiter soloensis) and Gray-faced Buzzards (Butastur indicus) during their southward migration in autumn 2019 at Kenting National Park, southern Taiwan, and 2020 in Yushan National Park, central Taiwan. At both watchsites, Gray-faced Buzzards started their migration journey about 1 hr earlier than Chinese Sparrowhawks. After adjusting for the local sunrise time, the first daily appearance time of Gray-faced Buzzards (–2.5 ± 9.3 min) was significantly earlier than that of Chinese Sparrowhawks (47.0 ± 29.3 min) by about 50 min at Kenting National Park. Though they initiated migration later in morning at montane stopover sites in Yushan National Park, the same trend was observed and with even greater difference, about 70 min. These results indicate that these two species migrate in different daily periods and suggest that Chinese Sparrowhawks might choose to exploit stronger thermal uplifts in September before leaving the island, as they started migration later in the morning. In contrast, Gray-faced Buzzards, a species more dependent on soaring-gliding flight, set off earlier in the day, probably to take advantage of stronger northeastern tailwinds that begin in October. We conclude that the prevailing monthly wind conditions, particularly influenced by the northeast monsoons, shape the different diurnal migration times of these two raptors migrating along the East-Asian Oceanic Flyway. RESUMEN.— Las estrategias que adoptan las rapaces migratorias durante la migración revelan sus adaptaciones a largo plazo a diferentes ambientes a lo largo de sus rutas migratorias y de sus sitios de parada. Registramos la hora de partida diaria de Accipiter soloensis y Butastur indicus durante su migración hacia el sur en el otoño de 2019 en el Parque Nacional Kenting, en el sur de Taiwán, y en 2020 en el Parque Nacional Yushan, en el centro de Taiwán. En ambos sitios de observación, B. indicus comenzó su migración aproximadamente 1 hora antes que A. soloensis. Después de ajustar por la hora local del amanecer, el primer horario diario de aparición de B. indicus (–2,5 ± 9,3 min) fue significativamente más temprano que el de A. soloensis (47,0 ± 29,3 min) por unos 50 min en Kenting. Aunque iniciaron la migración más tarde en la mañana en los sitios montanos de parada en Yushan, se observó la misma tendencia y con una diferencia aún mayor, alrededor de 70 min. Estos resultados indican que estas dos especies migran en diferentes períodos diarios y sugieren que A. soloensis podría optar por explotar corrientes térmicas ascendentes más fuertes en septiembre antes de abandonar la isla, ya que comenzó a migrar más tarde en la mañana. Por el contrario, B. indicus, una especie que depende más del vuelo planeado, partió más t","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":"1 1","pages":"344 - 351"},"PeriodicalIF":1.7,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83206562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marisela Martínez-Ruíz, C. Dykstra, Travis L. Booms, Michael T Henderson
Global climate change is an ongoing pervasive global conservation concern, with significant negative impacts for many species and populations. This Conservation Letter provides a scientific review of the effects of global climate change on raptors and concludes by highlighting potential mitigations and research needs. This letter is not intended as an exhaustive literature review. Rather, the intent of the Raptor Research Foundation (RRF) is to provide readers with enough evidence-based examples that they can appreciate the scope and prevalence of climate change impacts, understand their effects on raptor species and populations, and recognize some of the challenges associated with addressing climate change’s effects on raptors across regions. Climate change is caused by the release of atmospheric greenhouse gases (primarily carbon dioxide) resulting in changes in global climate-related parameters, mainly temperature and precipitation. In this scenario, the trend of increasing global temperatures is predicted to continue (Intergovernmental Panel on Climate Change [IPCC] 2021), influencing other climatic parameters and events. Increasing temperatures can impact raptors directly (e.g., Jaffré et al 2013, Dykstra et al. 2021b) and indirectly by driving disruptions to water cycles ranging from more frequent heavy precipitation events (Trenberth et al. 2003, Min et al. 2011, Anctil et al. 2014) to more severe drought (Cook et al. 2018, Smith et al. 2020). Further, the nature of climate events is also changing, encompassing more severe hurricanes and tropical cyclones (Emanuel 2005, 2013, Holland and Bruyère 2014), a poleward expansion of tropical cyclones (Studholme et al. 2022), and shifts in precipitation temporal trends (Dunning et al. 2018), exposing raptors to stochastic events. Climatic changes also alter the distributions of primary producers (Sturm et al. 2001, Tape et al. 2006) creating bottom-up effects that alter ecosystem function (i.e., ‘‘regime shifts’’; Rodionov 2004, Ripple et al. 2014). Moreover, the risk of wildlife extinctions is substantially accelerated by climate change (Urban 2015), and climate warming is related to the recent extinctions of at least one raptor (Sergio et al. 2021). This suggests there may be major negative effects of climate change for raptors (McClure et al 2018). Raptors are valuable and important study systems for investigating the effects of climate change because raptors are widespread, perform important ecological functions and can serve as flagship species for biodiversity (Donázar et al. 2016). As long-lived top predators holding large home ranges and preying on a wide variety of vertebrates and invertebrates, raptors are influenced by the effects of environmental change on lower trophic levels (Meserve et al. 2003, Schmidt et al. 2018) and can serve as biotic multipliers of climate change (Urban et al. 2017). Raptors have been the focus of multiple long-running studies on 1 The editorial processing and
全球气候变化是一个持续普遍存在的全球保护问题，对许多物种和种群产生了重大的负面影响。这封保护信提供了全球气候变化对猛禽影响的科学回顾，并在结论中强调了潜在的缓解措施和研究需求。这封信的目的不是作为一个详尽的文献综述。相反，猛禽研究基金会(RRF)的目的是为读者提供足够的基于证据的例子，使他们能够了解气候变化影响的范围和普遍性，了解它们对猛禽物种和种群的影响，并认识到与应对气候变化对跨地区猛禽的影响相关的一些挑战。气候变化是由于大气温室气体(主要是二氧化碳)的释放导致全球气候相关参数的变化，主要是温度和降水。在这种情景下，预计全球气温上升的趋势将继续(政府间气候变化专门委员会[IPCC] 2021)，影响其他气候参数和事件。气温升高可以直接影响猛禽(例如，jaffr等人2013年，Dykstra等人2021b)，也可以间接影响水循环，从更频繁的强降水事件(Trenberth等人2003年，Min等人2011年，Anctil等人2014年)到更严重的干旱(Cook等人2018年，Smith等人2020年)。此外，气候事件的性质也在发生变化，包括更严重的飓风和热带气旋(Emanuel 2005,2013, Holland and bruyre 2014)，热带气旋向极地扩展(Studholme et al. 2022)，以及降水时间趋势的变化(Dunning et al. 2018)，使猛禽暴露在随机事件中。气候变化也改变了初级生产者的分布(Sturm et al. 2001, Tape et al. 2006)，产生自下而上的影响，改变生态系统功能(即“政权转移”;Rodionov 2004, Ripple et al. 2014)。此外，气候变化大大加速了野生动物灭绝的风险(Urban 2015)，气候变暖与最近至少一种猛禽的灭绝有关(Sergio et al. 2021)。这表明气候变化可能对猛禽产生重大负面影响(McClure et al . 2018)。迅猛龙是调查气候变化影响的有价值和重要的研究系统，因为迅猛龙分布广泛，具有重要的生态功能，可以作为生物多样性的旗舰物种(Donázar et al. 2016)。猛禽作为长寿的顶级捕食者，拥有广阔的栖息地，捕食各种脊椎动物和无脊椎动物，受到环境变化对低营养水平影响的影响(Meserve等人，2003年，Schmidt等人，2018年)，可以作为气候变化的生物乘数(Urban等人，2017年)。猛禽一直是多个长期研究的焦点1 .本文的编辑处理和审查由副主编James F. Dwyer处理。2通讯作者:cheryldykstra@gmail.com
{"title":"Conservation Letter: Effects of Global Climate Change on Raptors","authors":"Marisela Martínez-Ruíz, C. Dykstra, Travis L. Booms, Michael T Henderson","doi":"10.3356/JRR-22-75","DOIUrl":"https://doi.org/10.3356/JRR-22-75","url":null,"abstract":"Global climate change is an ongoing pervasive global conservation concern, with significant negative impacts for many species and populations. This Conservation Letter provides a scientific review of the effects of global climate change on raptors and concludes by highlighting potential mitigations and research needs. This letter is not intended as an exhaustive literature review. Rather, the intent of the Raptor Research Foundation (RRF) is to provide readers with enough evidence-based examples that they can appreciate the scope and prevalence of climate change impacts, understand their effects on raptor species and populations, and recognize some of the challenges associated with addressing climate change’s effects on raptors across regions. Climate change is caused by the release of atmospheric greenhouse gases (primarily carbon dioxide) resulting in changes in global climate-related parameters, mainly temperature and precipitation. In this scenario, the trend of increasing global temperatures is predicted to continue (Intergovernmental Panel on Climate Change [IPCC] 2021), influencing other climatic parameters and events. Increasing temperatures can impact raptors directly (e.g., Jaffré et al 2013, Dykstra et al. 2021b) and indirectly by driving disruptions to water cycles ranging from more frequent heavy precipitation events (Trenberth et al. 2003, Min et al. 2011, Anctil et al. 2014) to more severe drought (Cook et al. 2018, Smith et al. 2020). Further, the nature of climate events is also changing, encompassing more severe hurricanes and tropical cyclones (Emanuel 2005, 2013, Holland and Bruyère 2014), a poleward expansion of tropical cyclones (Studholme et al. 2022), and shifts in precipitation temporal trends (Dunning et al. 2018), exposing raptors to stochastic events. Climatic changes also alter the distributions of primary producers (Sturm et al. 2001, Tape et al. 2006) creating bottom-up effects that alter ecosystem function (i.e., ‘‘regime shifts’’; Rodionov 2004, Ripple et al. 2014). Moreover, the risk of wildlife extinctions is substantially accelerated by climate change (Urban 2015), and climate warming is related to the recent extinctions of at least one raptor (Sergio et al. 2021). This suggests there may be major negative effects of climate change for raptors (McClure et al 2018). Raptors are valuable and important study systems for investigating the effects of climate change because raptors are widespread, perform important ecological functions and can serve as flagship species for biodiversity (Donázar et al. 2016). As long-lived top predators holding large home ranges and preying on a wide variety of vertebrates and invertebrates, raptors are influenced by the effects of environmental change on lower trophic levels (Meserve et al. 2003, Schmidt et al. 2018) and can serve as biotic multipliers of climate change (Urban et al. 2017). Raptors have been the focus of multiple long-running studies on 1 The editorial processing and","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":"9 1","pages":"92 - 105"},"PeriodicalIF":1.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76309734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When designing nest monitoring protocols for raptors, investigators face a tradeoff between the desire to detect all nesting attempts and limited time and resources. American Kestrel (Falco sparverius) nest box occupancy (i.e., traditionally defined as number of nest boxes used divided by number of nest boxes available) is often the principal metric for tracking kestrel population size and trend. However, traditional nest box monitoring can lead to underestimates of local population size when kestrel pairs establish territories at nest boxes but are undetected because they do not lay eggs or their nests fail early in the nesting cycle. We analyzed empirical data collected during frequent visits (1–7 d intervals) to nest boxes throughout the breeding season (March–June during 2008–2014) in a dynamic occupancy modeling framework to assess the timing and intensity of monitoring needed to detect (with the same confidence level provided by frequent visits) the presence of kestrels on nest box sites in Florida. Modeled estimates of occupancy were similar to observed rates but trended slightly higher, especially in years with infrequent monitoring. Detection probability varied markedly over the duration of the breeding season; therefore, using a constant detection probability to determine the minimum number of visits needed to detect kestrel presence at a 95% confidence level produced misleading results. Modeling results indicated that >3 nest box inspections per season did not improve estimates of nest box occupancy. The common practice of monitoring American Kestrel nest boxes at approximately monthly intervals appears sufficient to detect the percentage of nest box sites (rather than nest boxes) used by kestrels, provided that monitoring visits are timed to straddle the peak period of egg laying. We recommend three nest box visits during the breeding season in Florida coincident with mid-March, mid-April, and mid-to-late May to maximize detection of kestrel nests. Investigators in other areas of the species' range will need to adjust the timing of our recommendations to local phenology. In addition, if accurately tracking local kestrel population size and trend is a project goal, then studies would benefit from using an occupancy approach rather than simply recording the percentage of nest boxes with nests, especially in years when fewer visits are possible.
{"title":"Maximizing Nest Box Monitoring Effort To Detect American Kestrel Site Occupancy","authors":"K. Miller, Jessi L. Brown","doi":"10.3356/jrr-22-46","DOIUrl":"https://doi.org/10.3356/jrr-22-46","url":null,"abstract":"\u0000 When designing nest monitoring protocols for raptors, investigators face a tradeoff between the desire to detect all nesting attempts and limited time and resources. American Kestrel (Falco sparverius) nest box occupancy (i.e., traditionally defined as number of nest boxes used divided by number of nest boxes available) is often the principal metric for tracking kestrel population size and trend. However, traditional nest box monitoring can lead to underestimates of local population size when kestrel pairs establish territories at nest boxes but are undetected because they do not lay eggs or their nests fail early in the nesting cycle. We analyzed empirical data collected during frequent visits (1–7 d intervals) to nest boxes throughout the breeding season (March–June during 2008–2014) in a dynamic occupancy modeling framework to assess the timing and intensity of monitoring needed to detect (with the same confidence level provided by frequent visits) the presence of kestrels on nest box sites in Florida. Modeled estimates of occupancy were similar to observed rates but trended slightly higher, especially in years with infrequent monitoring. Detection probability varied markedly over the duration of the breeding season; therefore, using a constant detection probability to determine the minimum number of visits needed to detect kestrel presence at a 95% confidence level produced misleading results. Modeling results indicated that >3 nest box inspections per season did not improve estimates of nest box occupancy. The common practice of monitoring American Kestrel nest boxes at approximately monthly intervals appears sufficient to detect the percentage of nest box sites (rather than nest boxes) used by kestrels, provided that monitoring visits are timed to straddle the peak period of egg laying. We recommend three nest box visits during the breeding season in Florida coincident with mid-March, mid-April, and mid-to-late May to maximize detection of kestrel nests. Investigators in other areas of the species' range will need to adjust the timing of our recommendations to local phenology. In addition, if accurately tracking local kestrel population size and trend is a project goal, then studies would benefit from using an occupancy approach rather than simply recording the percentage of nest boxes with nests, especially in years when fewer visits are possible.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":"53 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91302361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Oleyar, L. Goodrich, D. Ethier, D. Brandes, Rebekah Smith, Julie Brown, Jason Sodergren
Using fall migration trend data from the Raptor Population Index analyses (n = 59 count sites) paired with winter Christmas Bird Count trend data at the USA state and Canadian province level, we evaluated continental and regional patterns in trends of American Kestrels (Falco sparverius) over the last 30 yr. Long-term trends at the continental and regional level showed widespread declines in the number of kestrels counted during both fall migration and winter. The lone exception was in western North America where declining migration counts were evident, but could at least partly be explained by increasing winter counts. These results suggest that western kestrels are shifting migratory tendencies, migrating shorter distances (short-stopping), or are not migrating at all. This contrasts with patterns in central and eastern North America where kestrel counts declined in both fall and winter over the last 20- and 30-yr periods. Recent trends (2009–2019) showed less widespread declines in both fall and winter across North America and for most regions, suggesting kestrel declines might have moderated in the past decade. However, the species remains at significantly reduced abundance levels compared to the recent past and has not rebounded.
{"title":"Thirty Years of Migration and Winter Count Data Indicate Regional Differences In Population Trajectories For American Kestrels In North America","authors":"D. Oleyar, L. Goodrich, D. Ethier, D. Brandes, Rebekah Smith, Julie Brown, Jason Sodergren","doi":"10.3356/jrr-22-17","DOIUrl":"https://doi.org/10.3356/jrr-22-17","url":null,"abstract":"\u0000 Using fall migration trend data from the Raptor Population Index analyses (n = 59 count sites) paired with winter Christmas Bird Count trend data at the USA state and Canadian province level, we evaluated continental and regional patterns in trends of American Kestrels (Falco sparverius) over the last 30 yr. Long-term trends at the continental and regional level showed widespread declines in the number of kestrels counted during both fall migration and winter. The lone exception was in western North America where declining migration counts were evident, but could at least partly be explained by increasing winter counts. These results suggest that western kestrels are shifting migratory tendencies, migrating shorter distances (short-stopping), or are not migrating at all. This contrasts with patterns in central and eastern North America where kestrel counts declined in both fall and winter over the last 20- and 30-yr periods. Recent trends (2009–2019) showed less widespread declines in both fall and winter across North America and for most regions, suggesting kestrel declines might have moderated in the past decade. However, the species remains at significantly reduced abundance levels compared to the recent past and has not rebounded.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":"938 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77555582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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