Sara J. Miller, C. Dykstra, Virginie Rolland, Melinda M. Simon, Jeffrey L. Hays, J. Bednarz
ABSTRACT. In many raptor species, hatching asynchrony results in a size hierarchy among nestlings, which may facilitate brood reduction by means of sibling aggression-induced mortality, especially in times of low food resources. However, few researchers have investigated the relationships among hatching asynchrony, sibling aggression, and nestling feeding rates in raptors. We studied the influence of hatch rank, brood size, and brood age on aggression and feeding rates among Red-shouldered Hawk (Buteo lineatus) nestlings in suburban southwestern Ohio. Despite relatively modest hatching asynchrony, nestling hatch rank (along with brood size and brood age) was an important predictor of the amount of aggression exhibited by individual nestlings. The oldest nestlings exhibited more aggressive behavior than younger nestlings, although they did not consume significantly more food. Aggression rates were higher in broods of three than broods of two nestlings, and aggression decreased from week 2 to week 3, post-hatching. However, hatch rank was not an important determinant of nestling food consumption, and food consumption rates were unrelated to sibling aggression rates. Identifiable prey delivered to nestling Red-shouldered Hawks was diverse and consisted of 28.3% birds, 25.7% mammals, 23.4% amphibians, 16.4% reptiles, and 6.2% invertebrates (by biomass). The relatively high percentage of birds in the diet may reflect food availability in the suburban habitat surrounding the nests. Sibling aggression did not result in direct siblicide in our study, but four nestlings apparently starved. Overall, the oldest Red-shouldered Hawk nestlings in our study established their dominance early but this was not associated with a detectable advantage in terms of food consumption. RESUMEN. En muchas especies de aves rapaces, la asincronía en la eclosión da como resultado una jerarquía de tamaño entre los polluelos, lo que puede facilitar la reducción de la nidada por medio de la mortalidad inducida por la agresión entre hermanos, especialmente en épocas de bajos recursos alimenticios. Sin embargo, pocos investigadores han estudiado las relaciones entre la asincronía en la eclosión, la agresión entre hermanos y las tasas de alimentación de los polluelos en las aves rapaces. Estudiamos la influencia del ranking de eclosión, el tamaño de la nidada y la edad de la nidada en la agresión y las tasas de alimentación entre polluelos de Buteo lineatus en los suburbios del suroeste de Ohio. A pesar de una asincronía en la eclosión relativamente moderada, el ranking de eclosión de los polluelos (junto con el tamaño y la edad de la nidada) fue un predictor importante de la cantidad de agresión exhibida por los polluelos individuales. Los polluelos mayores exhibieron un comportamiento más agresivo que los polluelos más jóvenes, aunque no recibieron una cantidad significativamente mayor de alimento. Las tasas de agresión fueron más altas en las nidadas de tres que en las nidadas d
摘要在许多猛禽物种中，孵化的不同步导致雏鸟之间的大小等级，这可能通过兄弟姐妹攻击引起的死亡来促进雏鸟数量的减少，特别是在食物资源匮乏的时候。然而，很少有研究人员调查了迅猛龙的孵化不同步、兄弟姐妹攻击和雏鸟摄食率之间的关系。本文研究了俄亥俄州西南郊区红肩鹰(Buteo lineatus)雏鸟的孵化等级、巢数和巢龄对其攻击性和摄食率的影响。尽管相对适度的孵化不同步，雏鸟孵化等级(以及窝的大小和窝的年龄)是一个重要的预测个体雏鸟表现出的攻击量。年龄最大的雏鸟表现出比年幼的雏鸟更具攻击性的行为，尽管它们消耗的食物并没有明显更多。三窝的攻击率高于两窝，并且在孵化后的第2周至第3周，攻击率下降。然而，孵化等级不是雏鸟食物消耗的重要决定因素，食物消耗率与兄弟姐妹攻击率无关。红肩鹰的可识别猎物种类繁多，其中鸟类占28.3%，哺乳动物占25.7%，两栖动物占23.4%，爬行动物占16.4%，无脊椎动物占6.2%(按生物量计算)。饮食中相对较高的鸟类比例可能反映了鸟巢周围郊区栖息地的食物供应情况。在我们的研究中，兄弟姐妹的攻击并没有直接导致兄弟姐妹的死亡，但四只雏鸟显然是饥饿的。总的来说，在我们的研究中，最老的红肩鹰雏鸟很早就确立了自己的统治地位，但这与食物消耗方面的明显优势无关。RESUMEN。就像其他国家一样，这些国家还包括:asincronía和eclosión . com和eclosión . com和eclosión . com和jerarquía . com和tamaño . com和eclosión . com和eclosión . com和reducción . com和agresión . com。com和eclosión . com和agresión . com。在禁运期间，pocos调查了两个研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心，一个是研究中心。Estudiamos la influiccia del ranking de eclosión, el tamaño de la nidada de la nidada de la agresión y las tasas de alimentación entre polluelos de Buteo lineatus de los suburbios del suroeste Ohio。A pesar de una asincronía en la eclosión relativamente moderada, el ranking de eclosión de los polluelos (junto con el tamaño y la edad de la nidada) fupredictor importante de la cantidad de agresión exhibida por los polluelos individuales。Los polluelos mayores exhibieron un comportamiento más积极的que Los polluelos más jóvenes，独特的没有recibieron uncantidad significativeente mayor de alimento。Las tasas de agresión fueron más altas en Las nidadas de res res de Las nidadas de res res res res污染者，la agresión disminuyó de la semana do a la semana res res res res despuveres de la eclosión。在禁运期间，我们的排名是eclosión没有确定的重要性，消费和食品的重要性，污染和污染的重要性，消费和食品的重要性，污染和污染之间的关系，以及消费和食品的重要性，污染和污染之间的关系。可识别的种类包括:鱼类28.3%，mamíferos 25.7%，抗生动物23.4%，爬行动物16.4%，无脊椎动物6.2%。El porcentaje relativamente alto de aves en la dieta puede reflejar la disabilidad de alimentos en hábitat suburbano que rodea los nidos。La agresión entre hermanos no resultó en un fratricicidio directo en nueststro estudio, pero aparentemente curo polluelos mureron de hambre。总而言之，污染指数(más)与污染指数(1 / 2)之间的差距(1 / 2)与污染指数(1 / 3)之间的差距(1 / 3)与污染指数(1 / 3)之间的差距(1 / 3)。[Traducción del equipo社论]
{"title":"Sibling Aggression, Feeding Rates, and Hatch Rank of Nestling Red-Shouldered Hawks (Buteo lineatus)","authors":"Sara J. Miller, C. Dykstra, Virginie Rolland, Melinda M. Simon, Jeffrey L. Hays, J. Bednarz","doi":"10.3356/JRR-22-76","DOIUrl":"https://doi.org/10.3356/JRR-22-76","url":null,"abstract":"ABSTRACT. In many raptor species, hatching asynchrony results in a size hierarchy among nestlings, which may facilitate brood reduction by means of sibling aggression-induced mortality, especially in times of low food resources. However, few researchers have investigated the relationships among hatching asynchrony, sibling aggression, and nestling feeding rates in raptors. We studied the influence of hatch rank, brood size, and brood age on aggression and feeding rates among Red-shouldered Hawk (Buteo lineatus) nestlings in suburban southwestern Ohio. Despite relatively modest hatching asynchrony, nestling hatch rank (along with brood size and brood age) was an important predictor of the amount of aggression exhibited by individual nestlings. The oldest nestlings exhibited more aggressive behavior than younger nestlings, although they did not consume significantly more food. Aggression rates were higher in broods of three than broods of two nestlings, and aggression decreased from week 2 to week 3, post-hatching. However, hatch rank was not an important determinant of nestling food consumption, and food consumption rates were unrelated to sibling aggression rates. Identifiable prey delivered to nestling Red-shouldered Hawks was diverse and consisted of 28.3% birds, 25.7% mammals, 23.4% amphibians, 16.4% reptiles, and 6.2% invertebrates (by biomass). The relatively high percentage of birds in the diet may reflect food availability in the suburban habitat surrounding the nests. Sibling aggression did not result in direct siblicide in our study, but four nestlings apparently starved. Overall, the oldest Red-shouldered Hawk nestlings in our study established their dominance early but this was not associated with a detectable advantage in terms of food consumption. RESUMEN. En muchas especies de aves rapaces, la asincronía en la eclosión da como resultado una jerarquía de tamaño entre los polluelos, lo que puede facilitar la reducción de la nidada por medio de la mortalidad inducida por la agresión entre hermanos, especialmente en épocas de bajos recursos alimenticios. Sin embargo, pocos investigadores han estudiado las relaciones entre la asincronía en la eclosión, la agresión entre hermanos y las tasas de alimentación de los polluelos en las aves rapaces. Estudiamos la influencia del ranking de eclosión, el tamaño de la nidada y la edad de la nidada en la agresión y las tasas de alimentación entre polluelos de Buteo lineatus en los suburbios del suroeste de Ohio. A pesar de una asincronía en la eclosión relativamente moderada, el ranking de eclosión de los polluelos (junto con el tamaño y la edad de la nidada) fue un predictor importante de la cantidad de agresión exhibida por los polluelos individuales. Los polluelos mayores exhibieron un comportamiento más agresivo que los polluelos más jóvenes, aunque no recibieron una cantidad significativamente mayor de alimento. Las tasas de agresión fueron más altas en las nidadas de tres que en las nidadas d","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86240783","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}
R. Petrov, I. Lazarova, D. Yarkov, Y. Andonova, Stefka Dimitrova
ABSTRACT. We collected blood samples from 44 Western Saker Falcons (Falco cherrug cherrug) and 68 Eastern Saker Falcons (Falco cherrug milvipes) in captivity at two facilities in Bulgaria to evaluate the health of individuals involved in a reintroduction project, and to gain insight into appropriate veterinary care and treatment of the birds. We compared the values of 18 biochemical parameters between the two subspecies and also between females and males. We found significant differences between the two subspecies for some of the parameters tested; however, they likely resulted from different feeding regimes at the two breeding facilities—one housing most of the Western Saker Falcons and the other all the Eastern Saker Falcons. Further tests should compare the biochemical values between birds of the two subspecies housed in the same facility. We also found significant differences in the biochemistry of female and male falcons across some parameters tested. After 20 yr without a record of Saker Falcons (Falco cherrug) nesting in Bulgaria, this globally endangered species has been successfully breeding there since 2018 as a result of an ongoing reintroduction project. By establishing baseline information on the differences in the biochemistry of Saker Falcons, our research may guide future studies of this rare species and aid veterinary care and treatment of the birds breeding in captivity. RESUMEN. Tomamos muestras de sangre de 44 individuos de Falco cherrug cherrug y de 68 individuos de Falco cherrug milvipes en cautividad en dos instalaciones en Bulgaria para evaluar la salud de los individuos involucrados en un proyecto de reintroducción, y para obtener información sobre los procedimientos de cuidado veterinario y de tratamiento de las aves. Comparamos los valores de 18 parámetros bioquímicos entre las dos subespecies y también entre hembras y machos. Encontramos diferencias significativas entre las dos subespecies para algunos de los parámetros evaluados; sin embargo, probablemente fueron el resultado de diferentes regímenes de alimentación en las dos instalaciones de cría: una albergaba a la mayoría de los individuos de F. c. cherrug y la otra a todos los individuos de F. c. milvipes. Las evaluaciones adicionales deberían comparar los valores bioquímicos entre las aves de las dos subespecies alojadas en la misma instalación. También encontramos diferencias significativas en la bioquímica de individuos machos y hembras en algunos parámetros probados. Después de 20 años sin registros de nidificación de F. cherrug en Bulgaria, esta especie en peligro de extinción a nivel mundial ha estado reproduciéndose exitosamente allí desde 2018 como resultado de un proyecto de reintroducción en curso. Al establecer información de base sobre las diferencias en la bioquímica de F. cherrug, nuestra investigación puede guiar los estudios futuros de esta rara especie y ayudar al cuidado veterinario y al tratamiento de las aves que se reproducen en cautividad. [T
摘要我们收集了保加利亚两个设施圈养的44只西部萨克猎鹰(Falco cherrug cherrug)和68只东部萨克猎鹰(Falco cherrug milvipes)的血液样本，以评估参与重新引入项目的个体的健康状况，并深入了解鸟类的适当兽医护理和治疗。我们比较了两个亚种之间以及雌雄之间18项生化指标的值。我们发现两个亚种在某些测试参数上存在显著差异;然而，它们可能是由于两个繁殖设施的不同喂养制度造成的——一个饲养大部分西部Saker猎鹰，另一个饲养所有东部Saker猎鹰。进一步的测试应比较同一设施中饲养的两个亚种鸟类的生化值。我们还发现，雌性和雄性猎鹰的生物化学在一些测试参数上存在显著差异。在保加利亚20年没有Saker Falcons (Falco cherrug)筑巢的记录之后，由于正在进行的重新引入项目，这种全球濒危物种自2018年以来在那里成功繁殖。通过建立Saker猎鹰生物化学差异的基线信息，我们的研究可以指导未来对这一稀有物种的研究，并帮助兽医护理和治疗圈养鸟类。RESUMEN。在保加利亚，有44人被宰杀，68人被宰杀，68人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀，1人被宰杀。comparative amos los valores de 18 parámetros bioquímicos entre las dos subspecies y tamamicass . entre embras y machos.。不同亚种间的显著性差异研究(parámetros evaluados)在禁运期间，可能会有一种不同的结果regímenes de alimentación，因为它可以安装到cría: una albergaba和la mayoría de de de f.c. cherrug的个人资料，以及la la la de de f.c. milvipes的个人资料。Las evaluaciones adicionales deberían compare los valores bioquímicos entre Las aves de Las dos subspecies alojadas en la misma instalación。tamamicans与其他个体(bioquímica de individuos machos)和其他个体(algunos parámetros probados)之间存在显著差异。2008年的数据汇总años在保加利亚的数据汇总中，特别是在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中，在保加利亚的数据汇总中。Al建立者información在基础上的区别在于bioquímica de F. cherrug, nuestra investigación在基础上的区别在于，在基础上的区别在于，在基础上的区别在于，在基础上的区别在于，在基础上的区别在于，在基础上的区别在于，在基础上的区别在于，在基础上的区别在于，在基础上的区别在于:[Traducción del equipo社论]
{"title":"First Biochemical Comparison Between Saker Falcon Subspecies Falco cherrug cherrug and Falco cherrug milvipes","authors":"R. Petrov, I. Lazarova, D. Yarkov, Y. Andonova, Stefka Dimitrova","doi":"10.3356/JRR-22-28","DOIUrl":"https://doi.org/10.3356/JRR-22-28","url":null,"abstract":"ABSTRACT. We collected blood samples from 44 Western Saker Falcons (Falco cherrug cherrug) and 68 Eastern Saker Falcons (Falco cherrug milvipes) in captivity at two facilities in Bulgaria to evaluate the health of individuals involved in a reintroduction project, and to gain insight into appropriate veterinary care and treatment of the birds. We compared the values of 18 biochemical parameters between the two subspecies and also between females and males. We found significant differences between the two subspecies for some of the parameters tested; however, they likely resulted from different feeding regimes at the two breeding facilities—one housing most of the Western Saker Falcons and the other all the Eastern Saker Falcons. Further tests should compare the biochemical values between birds of the two subspecies housed in the same facility. We also found significant differences in the biochemistry of female and male falcons across some parameters tested. After 20 yr without a record of Saker Falcons (Falco cherrug) nesting in Bulgaria, this globally endangered species has been successfully breeding there since 2018 as a result of an ongoing reintroduction project. By establishing baseline information on the differences in the biochemistry of Saker Falcons, our research may guide future studies of this rare species and aid veterinary care and treatment of the birds breeding in captivity. RESUMEN. Tomamos muestras de sangre de 44 individuos de Falco cherrug cherrug y de 68 individuos de Falco cherrug milvipes en cautividad en dos instalaciones en Bulgaria para evaluar la salud de los individuos involucrados en un proyecto de reintroducción, y para obtener información sobre los procedimientos de cuidado veterinario y de tratamiento de las aves. Comparamos los valores de 18 parámetros bioquímicos entre las dos subespecies y también entre hembras y machos. Encontramos diferencias significativas entre las dos subespecies para algunos de los parámetros evaluados; sin embargo, probablemente fueron el resultado de diferentes regímenes de alimentación en las dos instalaciones de cría: una albergaba a la mayoría de los individuos de F. c. cherrug y la otra a todos los individuos de F. c. milvipes. Las evaluaciones adicionales deberían comparar los valores bioquímicos entre las aves de las dos subespecies alojadas en la misma instalación. También encontramos diferencias significativas en la bioquímica de individuos machos y hembras en algunos parámetros probados. Después de 20 años sin registros de nidificación de F. cherrug en Bulgaria, esta especie en peligro de extinción a nivel mundial ha estado reproduciéndose exitosamente allí desde 2018 como resultado de un proyecto de reintroducción en curso. Al establecer información de base sobre las diferencias en la bioquímica de F. cherrug, nuestra investigación puede guiar los estudios futuros de esta rara especie y ayudar al cuidado veterinario y al tratamiento de las aves que se reproducen en cautividad. [T","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84227387","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}
M. Abé, Hiroshi K. Nakamura, A. Higuchi, Hirohiko Sano, Chikako Hashimoto
ABSTRACT. The Mountain Hawk Eagle (Nisaetus nipalensis orientalis) is classified as endangered in Japan and poorly studied throughout its range. We assessed prey fed to a nestling between hatching and fledging (16 April to 31 July) in central Japan. We used a time lapse camera to record prey deliveries and facilitate prey identification, and we estimated prey biomass and energy content across the nesting season. Of 140 prey items delivered to the single nestling, 65 (46.4%) were of five species of snake, 50 (35.7%) were of nine species of birds, 24 (17.1%) were of seven species of mammals, and one was unknown. The diurnal feeding rhythm showed a peak in prey deliveries at midday; all three classes of prey were delivered at various times of the day in a balanced manner. Snakes were especially prominent in the early stages of the brooding period, but diet shifted toward young birds and mammals in the latter half of the season when the prey species' young had become independent of their parents. Snakes made up the greatest percentage of biomass delivered, followed by mammals and then birds. However, mammals provided more energy per g of prey mass than birds and snakes. The adult eagles relied on large snakes awakened from hibernation in early spring, when prey was scarce, and then shifted to mammals with higher energy value during the peak growth period of the eaglet. An additional 233 prey remains collected from 31 other Mountain Hawk-Eagle nests comprised 20 species of birds and 10 species of mammals, and several unidentified snakes. Pooling results, we identified five species of snakes, 24 species of birds, and 14 species of mammals. These results add to the knowledge of the hawk-eagle's diet and will help to inform management of the species. RESUMEN. En Japón, Nisaetus nipalensis orientalis está clasificada como en peligro de extinción y ha sido relativamente poco estudiada en toda su área de distribución. Evaluamos las presas con que alimentaron a un polluelo entre la eclosión y el emplumamiento (16 de abril al 31 de julio) en el centro de Japón. Usamos una cámara rápida (time lapse) para registrar las entregas de presas y facilitar su identificación, y estimamos la biomasa y el contenido de energía de las presas durante la temporada de anidación. De las 140 presas entregadas a un solo polluelo, 65 (46.4%) pertenecieron a cinco especies de serpientes, 50 (35.7%) a nueve especies de aves, 24 (17.1%) a siete especies de mamíferos y una no fue identificada. El ritmo de alimentación diurno mostró un pico en las entregas de presas al mediodía; las tres clases de presas se entregaron en varios momentos del día de manera balanceada. Las serpientes fueron especialmente prominentes en las primeras etapas del período de cría, pero la dieta se desplazó hacia las aves jóvenes y los mamíferos en la segunda mitad de la temporada, cuando los juveniles de las especies presa se independizaron de sus progenitores. Las serpientes constituyeron el mayor porcentaje
摘要山鹰鹰(Nisaetus nipalensis orientalis)在日本被列为濒危物种，对其分布范围的研究很少。我们评估了日本中部雏鸟在孵化和羽化之间(4月16日至7月31日)喂养的猎物。我们使用延时摄像机来记录猎物的交付和方便猎物的识别，我们估计了整个筑巢季节猎物的生物量和能量含量。其中，5种蛇类65件(46.4%)，9种鸟类50件(35.7%)，7种哺乳动物24件(17.1%)，1件未知。白天的进食节奏显示，中午是猎物交付的高峰;这三种类型的猎物都在一天中的不同时间以平衡的方式被运送。在孵化期的早期阶段，蛇的作用尤为突出，但在繁殖季的后半段，当被捕食物种的幼鸟已经独立于它们的父母时，它们的饮食转向了年幼的鸟类和哺乳动物。蛇类所占的生物量比例最大，其次是哺乳动物，然后是鸟类。然而，哺乳动物比鸟类和蛇提供更多的能量。成鸟以早春时节从冬眠中醒来的大型蛇类为食，在幼鹰生长高峰期以能值较高的哺乳动物为食。另外，从其他31个山鹰巢中收集到的233具猎物遗骸包括20种鸟类和10种哺乳动物，以及几条身份不明的蛇。结果发现蛇类5种，鸟类24种，哺乳动物14种。这些结果增加了对鹰的饮食的了解，并将有助于为该物种的管理提供信息。RESUMEN。En Japón, Nisaetus nipalensis orientalis estestclassificada como En peligro de extinción y . sido relativamente poco estudiada En toda su área de distribución。1 .对污染中心(eclosión)和污染中心(Japón)(4月16日至7月31日)进行评估。Usamos una cámara rápida(时间延迟)para registrar las entregas de presas y facilitsu identificación, y estimamos la biomasa y el contenido de energía de presas durante la temporada de anidación。共发现140种单一污染，5种蛇类65种(46.4%)，5种蛇类50种(35.7%)，6种蛇类24种(17.1%)。El ritmo de alimentación diurno mostró un pico en enregas de presas al mediodía;这三种类型的压力和压力与不同时刻的压力和压力的平衡有关。Las serpientes fueron especientes enlas primeras etapas período de cría, pero la dieta se desplazó haacia Las aves jóvenes y los mamíferos en la secunda mitad de la temporada, cuando los juveniles de Las species presa se independdizaron de sus progenores。Las serpientes constituyeron el mayor porcentaje de biomasa entregada, seguidas穷人mamíferos y luego Las aves。在禁运期间，los mamíferos proporcionaron más energía por gramo de masa de presa que las serpientes。拉·阿古里亚·adultas dependieron de serpientes大despertaban de la hibernacion principios de la白桃花心木,cuando Las声部进入记号fueron escasas,采纳cambiaron mamiferos反对市长英勇energetico杜兰特el periodo de crecimiento maximo del aguilucho。共发现31种东方蛇，代表20种东方蛇和10种东方蛇。综合分析结果，鉴定出5种蛇属、24种蛇属、14种mamíferos属。Estos resulttados使用human al conocimiento de la dieta de n.n.orientalis通过ayudarán a mejorar el manejo de la especie。[Traducción del equipo社论]
{"title":"Food Habits of the Mountain Hawk-Eagle (Nisaetus nipalensis orientalis) During the Nesting Period in Japan","authors":"M. Abé, Hiroshi K. Nakamura, A. Higuchi, Hirohiko Sano, Chikako Hashimoto","doi":"10.3356/JRR-21-07","DOIUrl":"https://doi.org/10.3356/JRR-21-07","url":null,"abstract":"ABSTRACT. The Mountain Hawk Eagle (Nisaetus nipalensis orientalis) is classified as endangered in Japan and poorly studied throughout its range. We assessed prey fed to a nestling between hatching and fledging (16 April to 31 July) in central Japan. We used a time lapse camera to record prey deliveries and facilitate prey identification, and we estimated prey biomass and energy content across the nesting season. Of 140 prey items delivered to the single nestling, 65 (46.4%) were of five species of snake, 50 (35.7%) were of nine species of birds, 24 (17.1%) were of seven species of mammals, and one was unknown. The diurnal feeding rhythm showed a peak in prey deliveries at midday; all three classes of prey were delivered at various times of the day in a balanced manner. Snakes were especially prominent in the early stages of the brooding period, but diet shifted toward young birds and mammals in the latter half of the season when the prey species' young had become independent of their parents. Snakes made up the greatest percentage of biomass delivered, followed by mammals and then birds. However, mammals provided more energy per g of prey mass than birds and snakes. The adult eagles relied on large snakes awakened from hibernation in early spring, when prey was scarce, and then shifted to mammals with higher energy value during the peak growth period of the eaglet. An additional 233 prey remains collected from 31 other Mountain Hawk-Eagle nests comprised 20 species of birds and 10 species of mammals, and several unidentified snakes. Pooling results, we identified five species of snakes, 24 species of birds, and 14 species of mammals. These results add to the knowledge of the hawk-eagle's diet and will help to inform management of the species. RESUMEN. En Japón, Nisaetus nipalensis orientalis está clasificada como en peligro de extinción y ha sido relativamente poco estudiada en toda su área de distribución. Evaluamos las presas con que alimentaron a un polluelo entre la eclosión y el emplumamiento (16 de abril al 31 de julio) en el centro de Japón. Usamos una cámara rápida (time lapse) para registrar las entregas de presas y facilitar su identificación, y estimamos la biomasa y el contenido de energía de las presas durante la temporada de anidación. De las 140 presas entregadas a un solo polluelo, 65 (46.4%) pertenecieron a cinco especies de serpientes, 50 (35.7%) a nueve especies de aves, 24 (17.1%) a siete especies de mamíferos y una no fue identificada. El ritmo de alimentación diurno mostró un pico en las entregas de presas al mediodía; las tres clases de presas se entregaron en varios momentos del día de manera balanceada. Las serpientes fueron especialmente prominentes en las primeras etapas del período de cría, pero la dieta se desplazó hacia las aves jóvenes y los mamíferos en la segunda mitad de la temporada, cuando los juveniles de las especies presa se independizaron de sus progenitores. Las serpientes constituyeron el mayor porcentaje","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81526223","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}
K. N. Smith, W. A. Cox, K. Miller, Lauren L. Plussa
ABSTRACT. Swallow-tailed Kites (Elanoides forficatus) continue to rebound from population declines during the late 19th and early 20th centuries, and they are considered a species of concern in several southeastern states in the United States. During 2018–2019, we located and monitored 132 active Swallow-tailed Kite nests in and around the Corkscrew Regional Ecosystem Watershed Wildlife and Environmental Area in southwest Florida, USA, to determine how nest site characteristics affect nest survival. Including both years, the earliest active nest (with eggs or young) was discovered on 12 March and the latest nest fledged young on 23 July. Modeled survival of nests from the onset of incubation to fledging was 57.7% (95% CI: 44.5–68.9) and apparent nest survival was 48.7%. Daily survival rate was negatively correlated with ordinal date. Consequently, nests initiated early in the nesting season (mid-March) were more than three times as likely to fledge young as nests initiated late in the season (mid-May). Daily nest survival was positively correlated with nest tree diameter at breast height, indicating that Swallow-tailed Kites had greater nest survival when using larger, more mature trees. We found 99.0% (n = 102) of Swallow-tailed Kite nests in south Florida slash pine (Pinus elliottii var. densa) trees and one nest in bald cypress (Taxodium distichum). Trees used for nesting in our study area were among the largest nest trees reported for the species. Our results suggest that the large pine trees and large cypress trees formerly available in old growth bottomland hardwoods and lowland pine forests of the United States may have provided superior nesting opportunities for Swallow-tailed Kites. RESUMEN. Elanoides forficatus continúa recuperándose de las disminuciones poblacionales ocurridas a fines del siglo XIX y principios del XX y se considera una especie de preocupación en conservación en varios estados del sureste de los Estados Unidos. Durante 2018–2019, localizamos y seguimos 132 nidos activos de E. forficatus, dentro y en la periferia del Área de Vida Silvestre y Medio Ambiente de la Cuenca del Ecosistema Regional Corkscrew en el suroeste de Florida, EEUU, con el fin de determinar cómo las características del sitio de anidación afectan la supervivencia de los pollos en el nido. Incluyendo ambos años, nuestro primer nido activo (con huevos o crías) fue descubierto el 12 de marzo y el último volantón dejó el nido el 23 de julio. La supervivencia modelada de los nidos desde el inicio de la incubación hasta el emplumamiento fue del 57.7% (IC al 95%: 44.5–68.9) y la supervivencia aparente del nido fue del 48.7%. La tasa de supervivencia diaria se correlacionó negativamente con la fecha ordinal. En consecuencia, los nidos iniciados temprano en la temporada de anidación (mediados de marzo) tuvieron una probabilidad tres veces mayor de generar jóvenes volantones que los nidos iniciados al final de la temporada (mediados de mayo). La supervivencia di
摘要燕尾鸢(Elanoides forficatus)在19世纪末和20世纪初的数量下降中继续反弹，在美国东南部的几个州，它们被认为是一个值得关注的物种。在2018-2019年期间，我们在美国佛罗里达州西南部的Corkscrew区域生态系统流域野生动物和环境区及其周围定位并监测了132个活跃的燕尾风筝巢穴，以确定巢穴地点特征如何影响巢穴生存。包括这两年在内，最早的活动巢(有蛋或幼鸟)是在3月12日发现的，最近的巢是在7月23日发现的。巢从孵化开始到羽化的模型存活率为57.7% (95% CI: 44.5-68.9)，表观存活率为48.7%。日存活率与顺序日期呈负相关。因此，在筑巢季节早期(3月中旬)筑巢的巢孵出雏鸟的可能性是在筑巢季节后期(5月中旬)筑巢的巢的三倍多。巢日存活率与胸高处巢树直径呈正相关，表明使用更大、更成熟的树时，燕尾鸢的巢存活率更高。在南佛罗里达的湿球松(Pinus elliottii var. densa)上发现99.0% (n = 102)的燕尾鸢巢，在秃柏树(Taxodium distichum)上发现1个燕尾鸢巢。在我们的研究区域用于筑巢的树木是该物种报道的最大的筑巢树之一。我们的研究结果表明，以前生长在美国低洼阔叶林和低地松林中的大松树和大柏树可能为燕尾鸢提供了优越的筑巢机会。RESUMEN。Elanoides forficatus连续recuperandose de las disminuciones poblacionales ocurridas罚款del第十九siglo y principios del XX y se推崇una especie各类estado de preocupacion en conservacion en del sureste de los美国。2018-2019年，在美国佛罗里达州的调查中，环境科学与环境研究中心(环境科学与环境研究中心)，环境科学与环境研究中心(环境科学与环境研究中心)，环境科学与环境研究中心(环境科学与环境研究中心)，环境科学与环境研究中心(环境科学与环境研究中心)。包括endendo ambos años, nuestro primer nido activo (con huevos o crías) fudecubierto el 12 de marzo和el último volantón dejó el nido el 23 de julio。La supervivencia modelada de los nidos des inicio de La incubación hasta el emplumamiento fute del 57.7% (IC 95%: 44.5-68.9)， La supervivencia aparente del nidote del 48.7%。La tasa de supervivencia diaria se correlacionó negative - vamente con La fecha ordinal。En consecuencia, los nidos iniciados temprado En la temporada anidación (mediados de marzo)， tuvieras unprobabilidad tres es mayor de generes jóvenes火山爆发，los nidos iniciados al final de la temporada (mediados de mayo)。全国人民的生活状况监测correlacionó diámetro全国人民的生活状况监测árbol，全国人民的生活状况监测diámetro全国人民的生活状况监测árbol，全国人民的生活状况监测diámetro全国人民的生活状况监测usó árboles más全国人民的生活状况监测。(n = 102)对佛罗里达南部的松(Pinus elliottii var. densa)和对西部的松(Taxodium distichum)有99.0% (n = 102)的污染。Los árboles use zados para anidar en nuestra área de estudio se encuentran entre Los árboles de anidación más grandes reportados para la especie。新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果表明，新结果。[Traducción del equipo社论]
{"title":"Ordinal Date and Tree Diameter Influence Swallow-Tailed Kite (Elanoides forficatus) Nest Survival","authors":"K. N. Smith, W. A. Cox, K. Miller, Lauren L. Plussa","doi":"10.3356/JRR-22-69","DOIUrl":"https://doi.org/10.3356/JRR-22-69","url":null,"abstract":"ABSTRACT. Swallow-tailed Kites (Elanoides forficatus) continue to rebound from population declines during the late 19th and early 20th centuries, and they are considered a species of concern in several southeastern states in the United States. During 2018–2019, we located and monitored 132 active Swallow-tailed Kite nests in and around the Corkscrew Regional Ecosystem Watershed Wildlife and Environmental Area in southwest Florida, USA, to determine how nest site characteristics affect nest survival. Including both years, the earliest active nest (with eggs or young) was discovered on 12 March and the latest nest fledged young on 23 July. Modeled survival of nests from the onset of incubation to fledging was 57.7% (95% CI: 44.5–68.9) and apparent nest survival was 48.7%. Daily survival rate was negatively correlated with ordinal date. Consequently, nests initiated early in the nesting season (mid-March) were more than three times as likely to fledge young as nests initiated late in the season (mid-May). Daily nest survival was positively correlated with nest tree diameter at breast height, indicating that Swallow-tailed Kites had greater nest survival when using larger, more mature trees. We found 99.0% (n = 102) of Swallow-tailed Kite nests in south Florida slash pine (Pinus elliottii var. densa) trees and one nest in bald cypress (Taxodium distichum). Trees used for nesting in our study area were among the largest nest trees reported for the species. Our results suggest that the large pine trees and large cypress trees formerly available in old growth bottomland hardwoods and lowland pine forests of the United States may have provided superior nesting opportunities for Swallow-tailed Kites. RESUMEN. Elanoides forficatus continúa recuperándose de las disminuciones poblacionales ocurridas a fines del siglo XIX y principios del XX y se considera una especie de preocupación en conservación en varios estados del sureste de los Estados Unidos. Durante 2018–2019, localizamos y seguimos 132 nidos activos de E. forficatus, dentro y en la periferia del Área de Vida Silvestre y Medio Ambiente de la Cuenca del Ecosistema Regional Corkscrew en el suroeste de Florida, EEUU, con el fin de determinar cómo las características del sitio de anidación afectan la supervivencia de los pollos en el nido. Incluyendo ambos años, nuestro primer nido activo (con huevos o crías) fue descubierto el 12 de marzo y el último volantón dejó el nido el 23 de julio. La supervivencia modelada de los nidos desde el inicio de la incubación hasta el emplumamiento fue del 57.7% (IC al 95%: 44.5–68.9) y la supervivencia aparente del nido fue del 48.7%. La tasa de supervivencia diaria se correlacionó negativamente con la fecha ordinal. En consecuencia, los nidos iniciados temprano en la temporada de anidación (mediados de marzo) tuvieron una probabilidad tres veces mayor de generar jóvenes volantones que los nidos iniciados al final de la temporada (mediados de mayo). La supervivencia di","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84180261","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}
Syartinilia, Y. Mulyani, Rofifah Aulia Suyitno, A. A. Condro, S. Tsuyuki, S. (. V. Balen
{"title":"Population Estimates of the Endangered Javan Hawk-Eagle Based on Habitat Distribution Modeling and Patch Occupancy Surveys","authors":"Syartinilia, Y. Mulyani, Rofifah Aulia Suyitno, A. A. Condro, S. Tsuyuki, S. (. V. Balen","doi":"10.3356/jrr-22-16","DOIUrl":"https://doi.org/10.3356/jrr-22-16","url":null,"abstract":"","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80616296","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":"Wilted Wings: A Hunter's Fight for Eagles","authors":"Jeremy A. Buck","doi":"10.3356/jrr-book-review","DOIUrl":"https://doi.org/10.3356/jrr-book-review","url":null,"abstract":"","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45122021","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}
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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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}
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