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Nonbreeding raptors are vulnerable to many anthropogenic changes such as habitat fragmentation and increasing risk of collision (e.g., with wind turbines, powerlines, or vehicles). One aspect of habitat quality for raptors during winter has received comparably less attention: the role of colonial burrowing rodents such as prairie dogs (Cynomys spp.) as a reliable food source, and the effects of widespread reduction in prairie dog abundance and availability to nonbreeding raptors. We used a historical dataset (1998–2002) of roadside surveys for raptors and prairie dogs in the Southern and Central Great Plains, including Arizona, Colorado, New Mexico, and Texas, USA, and the Mexican state of Chihuahua, to provide the most spatially and temporally expansive analysis to date of the potential role of prairie dogs in influencing presence and abundance of raptors. We assessed patterns of co-occurrence among raptors and prairie dogs and modeled the response of selected species to weather, latitude, grassland cover, and prairie dog presence and abundance at multiple spatial scales. During the study period, we detected 19 species of raptors and identified nine raptor species that co-occurred with prairie dogs more than expected by chance. We also found evidence that occurrence of prairie dogs was related to presence and/or abundance of Ferruginous Hawks (Buteo regalis), Golden Eagles (Aquila chrysaetos), Bald Eagles (Haliaeetus leucocephalus), and Rough-legged Hawks (B. lagopus). Our work underscores the association of prairie dogs with many wintering raptor species, especially Ferruginous Hawks and Golden Eagles, and indicates that prairie dogs may also be an important resource for Rough-legged Hawks and Bald Eagles during the nonbreeding season. Las rapaces no reproductoras son vulnerables a muchos cambios antropogénicos, como la fragmentación del hábitat y el aumento del riesgo de colisión (por ejemplo, con aerogeneradores, líneas eléctricas o vehículos). Un aspecto de la calidad del hábitat para las rapaces durante el invierno ha recibido comparativamente menos atención: el papel de roedores coloniales que excavan madrigueras, como los perritos de las praderas (Cynomys spp.), como una fuente confiable de alimento, y los efectos de la reducción generalizada en la abundancia y disponibilidad de perritos de las praderas para las rapaces no reproductoras. Utilizamos una serie de datos histórica (1998–2002) de censos en carreteras de rapaces y perritos de las praderas en las Grandes Llanuras del sur, que incluyen Arizona, Colorado, Nuevo México y Texas, EEUU, y el estado mexicano de Chihuahua, para proporcionar el análisis espacial y temporal más amplio hasta la fecha sobre el papel potencial de los perritos de las praderas en la influencia de la presencia y abundancia de rapaces. Evaluamos patrones de coocurrencia entre rapaces y perritos de las praderas y modelamos la respuesta de especies seleccionadas a factores como el clima, la latitud, la cobertura de pastizales y la presencia y abundancia de perritos de las praderas considerando múltiples escalas espaciales. Durante el período de estudio, detectamos 19 especies de rapaces e identificamos nueve especies de rapaces que coocurrieron con perritos de las praderas más de lo esperado por azar. También encontramos evidencia de que la presencia de perritos de las praderas estaba relacionada con la presencia y/o abundancia de Buteo regalis, Aquila chrysaetos, Haliaeetus leucocephalus, y B. lagopus. Nuestro trabajo destaca la asociación de los perritos de las praderas con muchas especies de rapaces invernantes, especialmente con B. regalis y A. chrysaetos, e indica que los perritos de las praderas también pueden ser un recurso importante para B. lagopus y H. leucocephalus durante la temporada no reproductiva. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

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. 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 de biomasa entregada, seguidas por los mamíferos y luego las aves. Sin embargo, los mamíferos proporcionaron más energía por gramo de masa de presa que las aves y las serpientes. Las águilas adultas dependieron de serpientes grandes que despertaban de la hibernación a principios de la primavera, cuando las presas fueron escasas, y luego cambiaron a mamíferos con mayor valor energético durante el período de crecimiento máximo del aguilucho. Otros 233 restos de presas recolectados de 31 nidos adicionales de N. n. orientalis representaron 20 especies de aves y 10 especies de mamíferos, y varias serpientes no identificadas. Combinando los resultados, identificamos cinco especies de serpientes, 24 especies de aves y 14 especies de mamíferos. Estos resultados se suman al conocimiento de la dieta de N. n. orientalis y ayudarán a mejorar el manejo de la especie. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

I evaluated the breeding biology of Red-headed Falcon (Falco chicquera) by documenting 39 breeding attempts in Surendranagar district of Gujarat, India, from 2006 to 2021. Across years, the Mayfield estimated seasonal nest survival was 0.900 ± 0.016 (95% CI), and productivity was 2.5 ± 1.4 (95% CI) fledglings per breeding attempt. Prey deliveries recorded during the study were exclusively birds, 71% of the order Passeriformes. Of the 39 breeding attempts in 18 territories, 26 nests were on high tension electricity transmission pylons and 13 were in trees. I provide the first baseline data for comparing and evaluating reproductive rate of this species in different environments across the Indian subcontinent and elsewhere. Evalué la biología reproductiva de Falco chicquera documentando 39 intentos reproductivos en el distrito de Surendranagar de Gujarat, India, de 2006 a 2021. A lo largo de los años, la supervivencia estacional de los nidos, estimada por el método de Mayfield, fue de 0.900 ± 0.016 (IC del 95%), y la productividad fue de 2.5 ± 1.4 (95% IC) volantones por intento reproductivo. Las entregas de presas registradas durante el estudio fueron exclusivamente aves, con el 71% pertenecientes al Orden Passeriformes. De los 39 intentos reproductivos en 18 territorios, 26 nidos fueron colocados sobre postes eléctricos de alta tensión y 13 en árboles. Proporciono los primeros datos de referencia para comparar y evaluar la tasa reproductiva de esta especie en diferentes ambientes en el subcontinente indio y en otros lugares. [Traducción del equipo editorial] [ABSTRACT FROM AUTHOR]

The article titled "Turtles as Prey of Crested Caracaras (Caracara plancus) on the Katy Prairie, Texas" discusses the diet of Crested Caracaras, a bird species that consumes a variety of foods including turtles. The authors observed a pair of adult caracaras carrying small turtles to their fledglings in a specific location on the Katy Prairie in Texas. They found numerous small turtle carcasses beneath a sugarberry tree, indicating that caracaras regularly prey on turtles. This observation raises conservation concerns, particularly for the western chicken turtle, a subspecies that is under threat from urbanization in Texas. Further study is needed to determine the impact of caracara predation on western chicken turtles in the area. [Extracted from the article]

The article discusses that the Ospreys (Pandion haliaetus) are obligate piscivores and their nesting success depends on sufficient amounts of fish delivered to the nests during the breeding season.

The Crested Eagle (Morphnus guianensis) is the second largest Brazilian forest eagle. Crested Eagles are distributed from southeastern Mexico to southern Brazil, northern Argentina, and Paraguay; however, the species is one of the least-studied Neotropical raptors. Our objective was to determine diet and feeding strategies for Crested Eagles in the Brazilian Amazon. We recorded Crested Eagle diet at four nests from 2010–2012 through a combination of direct observations from the ground, remote photographs (camera-traps), and pellets and prey remains collected in and under the nests. We identified a total of 79 prey individuals, composed of 21 different prey species. We found that Crested Eagles fed mainly on medium-sized rodents, and medium-sized to large mammals. Prey were mainly nocturnal (70%), including mostly scansorial, cavity-dwelling marsupials and rodents. Fewer prey were diurnal (20%) and these were typified by arboreal, gregarious mammals (monkeys); rare prey included one owl (Strigidae) and one porcupine (Coendou sp.). We suggest that this may indicate a diet not specialized on a particular prey species or group, but rather focused on specific prey behaviors or microhabitats. [ABSTRACT FROM AUTHOR]

The Austral Peregrine Falcon (Falco peregrinus cassini) is widely distributed in Argentina, although studies on its diet are limited. Here we report information on the diet of this falcon in southern Atlantic Patagonia, Argentina. During November and December in 2009 and 2010, we visited nest sites of Austral Peregrine Falcons to collect prey remains to investigate their diet during the breeding season. We identified 72 avian prey remains from seven eyries in 2009 and three eyries in 2010. We documented seven orders of nonpasserines (11 families representing at least 58 individuals [81% of total prey items]). For the order Passeriformes, seven families were represented by 14 individual birds (19% of total prey items). In all, we identified 52 prey remains (72% of total prey items) to the species level. Another 12 birds were identified only to genus and three only to family or subfamily. Body mass for avian prey identified to species (n = 51) ranged from 10.4 g (Troglodytes aedon) to 842 g (Mareca sibilatrix). Nonpasserines provided 96.2% of the estimated biomass of the prey. Although our sample size is limited, compared with previous reports conducted more than 30 yr ago or in recent years but limited to one pair, our observations for ten nests in 2 yr provide novel and current information on avian prey species of Austral Peregrine Falcons. Our study increased the number of prey species documented for these birds for a geographical region where diet information was almost nonexistent, and provided diet data for both the typical and pallid color morphs of this subspecies. [ABSTRACT FROM AUTHOR]

Studies of cliff-nesting raptors can be challenging because direct observations of nest contents are difficult. Our goals were to develop a protocol for installing motion-activated trail cameras at Golden Eagle (Aquila chrysaetos) nests to record diet information and productivity, and to estimate prey detection probability using different diet study methods. In 2014 and 2015, we installed cameras at 12 Golden Eagle nests with 18–42-d-old nestlings. Following installation, we monitored adult behavior using direct observation and post-installation image review. At two nests, adult eagles did not return to nests or exhibited behaviors suggesting avoidance of the cameras, but returned to the nests after cameras were removed. We visited the 10 remaining nests every 4 d to collect prey remains and pellets to generate prey-specific detection estimates for both images, and prey remains and pellets. Compared to inspection of prey remains and pellets, cameras recorded twice the number of prey (622 vs. 316), were more likely to detect the smallest and largest prey, and cost half as much. Cameras recorded productivity, fledging dates, and in one case, a nestling death. Trail cameras may be a reliable and cost-effective option to address clearly defined research goals and obtain required information about eagle behavior and nest contents. However, cameras should be used judiciously because installation creates a persistent manipulation at the nest. Camera appearance should be minimized, and post-installation monitoring that allows for timely responses to nest-avoidance behavior by adult eagles is important to prevent adverse effects on nesting success. [ABSTRACT FROM AUTHOR]

The Snowy Owl (Bubo scandiacus) is a rare resident species in Iceland and nests have been found intermittently. Nests are unusual because lemmings (Dicrostonyx spp. and Lemmus spp.), the primary prey of the Snowy Owl across much of its distribution, do not occur in Iceland. We studied summer diets by analyzing pellets from three areas in Iceland where owls were detected; breeding was confirmed at two of these sites. We identified 257 prey items (total mass of 73.6 kg) of at least 13 species. Birds made up most of the diet (96.5% by number). The Rock Ptarmigan (Lagopus muta) was the primary prey species (30.4%). Shorebirds were important prey (46.2%), and passerines (5.1%), as well as waterfowl (6.3%), were also taken. Wood mice (Apodemus sylvaticus; 2.7%) and Arctic fox pups (Vulpes lagopus; 0.8%) were taken occasionally. Adult prey birds made up 60.3% and nestlings 36.3% of the diet by number. [ABSTRACT FROM AUTHOR]

We studied the diet and prey delivery behavior of Burrowing Owls (Athene cunicularia hypugaea) during the breeding season in the southeastern Chihuahuan desert, Mexico. The diet of the Burrowing Owl included 8 orders, 13 invertebrate families, and 5 genera of mammals, gastropods, reptiles, and birds. By frequency, invertebrates (Orthoptera, Coleoptera, Hymenoptera, and Hemiptera) were the most common prey, with vertebrates making up a much smaller proportion. However, by biomass, owls consumed mainly vertebrates (56.7%). Among invertebrates, the families Tenebrionidae and Acrididae accounted for 33.2% of the total consumed biomass. Females delivered more prey items than males (55.6% and 44.4%, respectively). Our observations contribute to our knowledge of the ecology of this owl in a region where it has been little studied. [ABSTRACT FROM AUTHOR]

The article focuses on Eurasian Sparrowhawk (Accipiter nisus) is a small bird of prey distributed throughout Europe and Asia and closely linked to forest environments. Topics include the male Eurasian Sparrowhawk typically captures small birds whereas females prey on larger birds, and the females gradually start hunting as the nestlings demand more food.

From 2005 to 2009 we evaluated the activity patterns and food habits of White-tailed Kites (Elanus leucurus) during the breeding and nonbreeding seasons in the Argentine Pampas. According to time-activity budget analyses, perching was the most frequently observed activity during the nonbreeding season (52% of total time), whereas foraging was the most frequent activity during the breeding season (41% of total time). Flight was the least frequent of all kites' activities in both seasons (8% and 9% during the breeding and nonbreeding season, respectively). Even when kites spent a similar percentage of time foraging during both breeding and nonbreeding seasons (41% and 39%, respectively), their hunting technique differed between seasons. During the nonbreeding season, we only observed kites using active searching to forage, but during the breeding season, we observed them using active and passive searching in similar proportions. According to pellet analyses, the diet of kites was mostly composed of rodents (> 96% of total prey). Small rodents (body mass < 35 g) were dominant in numeric terms in the diet in both seasons, but larger rodents represented the bulk of biomass. Our results indicate that in the Argentine Pampas, White-tailed Kites are predominantly mammal-eating, active-search predators, as previously reported for the species in South America and North America and for other Elanus species around the world. [ABSTRACT FROM AUTHOR]

Abstract Although best known for capturing live prey, five of the six members of the genus Falco in the United States or Canada are documented facultative scavengers. During 1109 surveys of three coastal beaches in Washington between 1983 and 2015, we observed hunting and feeding by Peregrine Falcons (Falco peregrinus), a species that migrates through and overwinters at those coastal beaches. Excluding records of Peregrine Falcons with food items of unknown origin (n = 44), our 172 observations of feeding included 77 prey items that we concluded the falcons had captured, 46 direct observations of prey captures, and 49 cases of scavenging. Scavenging records represented 29% of our observations of Peregrine Falcons with food items, and included food items representing 19 taxa. Seabirds and waterbirds were the most common food items consumed as carrion (44 of 49 items; 90%), whereas other captured or targeted prey were most often shorebirds or other small birds (206 of 277 items; 74%). We observed 21 color-banded falcons, ranging in age from <1 to 4 yr, scavenging up to three times each. We observed more scavenging by immature (<1 yr old) falcons than by adults, even though hunting success was similar between immature and adult falcons. We detected no difference in the occurrence of scavenging by season. Given the frequency of scavenging, the biomass of carrion potentially consumed, and the apparently predictable presence of carrion in the study area, we concluded that scavenging by peregrines in coastal Washington is relatively common. Additionally, carrion may represent a commonly used and important source of food in other regions of the world, particularly where carrion is common and persistent in the environment. [ABSTRACT FROM AUTHOR]

Abstract The Forest Owlet (Heteroglaux blewitti), Spotted Owlet (Athene brama) and Jungle Owlet (Glaucidium radiatum) are small owls coexisting in the East Kalibhit Forests in the Khandwa District of Madhya Pradesh State, India. We compared their diets to better understand their food habits, dietary overlap, and the mechanism of their coexistence. The diet of the three species differed significantly. The diet of the Forest Owlet was dominated by small mammals (52.2%, by frequency), whereas invertebrates dominated the diets of the Spotted Owlet (58.1%) and Jungle Owlet (84.8%). The Forest Owlet consumed a wider array of prey (food-niche breadth [FNB] = 0.40) compared to the Spotted Owlet (FNB = 0.13) and the Jungle Owlet (FNB = 0.06). The dietary overlap was highest between the Forest Owlet and Spotted Owlet (56%), lower between the Spotted and Jungle Owlet (28%), and lowest between the Forest and Jungle Owlet (22%). Diets also differed significantly among the three owls in terms of the mean prey mass of the species consumed. The Forest Owlet is a generalist predator feeding on various sizes and types of prey; the Spotted Owlet feeds on large and medium-sized mammals, as well as invertebrates, and the Jungle Owlet is a specialist feeding mainly on invertebrates and small mammals. Our results suggest the three species coexist by consuming prey of different sizes. [ABSTRACT FROM AUTHOR]

The Mottled Wood-Owl ( Strix ocellata) is a poorly studied species endemic to the Indian subcontinent. During nine nesting seasons from 2005-2016, we studied 15 breeding pairs near Pune, west-central India. Important nest tree species were mango ( Mangifera indica, 52%) and tamarind ( Tamarindus indica, 22%). Habitat in plots with a 0.5-km radius centered on the nest comprised a mosaic of agricultural landscapes (41.9 ± 17.7%), deciduous/scrub forests (16.8 ± 21.8%), natural grasslands (15.0 ± 8.2%), human habitation (11.2 ± 8.5%), streams/rivers (10.1 ± 4.6%), and low hills (5.0 ± 5.8%). In a subset of five nests where the entire breeding cycle was studied, the average clutch size was 2.6 eggs (±0.5 SD, n = 20 breeding attempts [eggs laid]), of which an average 2.2 (± 0.4) young hatched, and 1.9 (±0.8) young fledged/ breeding attempt. In addition, among ten other pairs where the nests were detected at the stage of fledging of young, an average of 1.6 young (±0.7, range = 1-4) fledged / successful nest. The primary nesting season from egg-laying to fledging lasted from 10 February until 20 May. From 1033 pellets analyzed, we identified 711 prey, including insects (39%), small mammals (rodents 10%; shrews 21%, bats 3%), birds (11%), and reptiles (9%). [ABSTRACT FROM AUTHOR]

In October 2017, we opportunistically observed up to 50 Peregrine Falcons (Falco peregrinus) on a ship moored in the western Gulf of Mexico. All birds we aged were juveniles, and they hunted from the ship, frequently perching extremely close to one another (<1 m apart) on cables. Both the number of birds and also the very short inter-individual distances when perching make these observations unusual among the published reports for this species. [ABSTRACT FROM AUTHOR]

I studied the diet of the Golden Eagle ( Aquila chrysaetos) in western Iran by identifying food items in prey remains, pellets, and video recordings at seven nests during the 2011-2013 breeding seasons. Two methods were used to calculate diet composition: minimum number of individuals of each prey species and estimated biomass for prey items. I identified 316 prey items, which included five species of birds, four species of mammals, and two species of reptiles. Mammals made up the greatest proportion of the diet, 44.0% by frequency and 76.8% by biomass, and birds accounted for 43.7% of the diet by frequency and 17.7% by biomass. Cape hare ( Lepus capensis), Chukar ( Alectoris chukar), Common Magpie ( Pica pica), large-toothed souslik ( Spermophilus fulvus) and common fox ( Vulpes vulpes) were the most important prey species. The percentage of mammals in the Golden Eagle's diet in western Iran was lower than in North America, Scotland, the mountains of the Mediterranean, and across Europe and Asia. [ABSTRACT FROM AUTHOR]

Urban ecosystems are attractive to several raptor species, including the Mississippi Kite ( Ictinia mississippiensis). To better understand the niche filled by urban-nesting Mississippi Kites, we observed nesting kites at 10 nests for a total of 269 hr during the breeding seasons of 2010 and 2011. We assessed prey delivery rates and prey use within and between years, evaluated the influences of nestling age, time of day, day of year, and local atmospheric conditions on delivery rates, and examined provisioning rates by male and female kites. A 62% decrease in the prey delivery rate, measured by the number of prey deliveries, from 2010 to 2011 was likely attributable to extreme heat and drought during the 2011 breeding season. However, total biomass of identified deliveries increased 38.9% in 2011 due to an increase in the percentage of avian prey (from 1% to 16% of identified deliveries). We suspect that differences in weather conditions between years influenced the type of prey delivered, and our modeling efforts indicated that year, nestling age, time of day, and temperature best explained the number of prey deliveries made per hour. On average, females delivered more prey items than males, but variability among nests suggested additional factors may influence parental effort. Our results suggest that Mississippi Kites exhibit prey switching under differing conditions. [ABSTRACT FROM AUTHOR]

We document concentrations of total mercury (Hg) in feathers of Peregrine Falcons ( Falco peregrinus) from 12 territories in Lake Mead National Recreation Area (LMNRA) and five territories in an adjacent southern Nevada (SNV) study area during 2012 and 2013. We also report total Hg concentrations in feathers of 94 species (337 individuals) collected as prey remains from peregrine nesting areas from 2008-2013. All peregrine feathers contained total Hg (range = 0.12-42.54 µg/g), and adults had a significantly higher mean total Hg concentration (12.19 µg/g) than hatch-year peregrines (3.76 µg/g). Mean total Hg concentrations in peregrines in LMNRA (adult = 17.24 µg/g, brood = 5.82 µg/g) were significantly greater than in SNV (adult = 2.7 µg/g, brood = 0.67 µg/g) for both age classes. Among peregrine territories, mean total Hg in prey was positively correlated with the proportion of aquatic birds taken as prey (biomass), and negatively correlated with distance of eyries to water. Among avian prey, the mean total Hg concentration in aquatic birds (5.07 µg/g) was significantly higher than terrestrial birds (0.76 µg/g), and aquatic invertivores were the most contaminated foraging guild (mean = 6.17 µg/g). Eared Grebes ( Podiceps nigricollis) were the prey species with the highest mean total Hg concentration (12.27 µg/g). Peregrine Falcons, with their broad distribution, catholic diet, and use of diverse habitat types, may be an ideal indicator species of environmental Hg contamination. Contaminant studies incorporating prey analysis are useful to assess exposure pathways and evaluate potential ecological effects across a broad array of habitat types. Documentamos las concentraciones totales de mercurio (Hg) en plumas de individuos de Falco peregrinus procedentes de 12 territorios ubicados en el Área Recreativa Nacional Lago Mead (ARNLM) y de cinco territorios de un área de estudio colindante ubicada al sur de Nevada (SNV) durante 2012 y 2013. También reportamos concentraciones totales de Hg en plumas de 94 especies (337 individuos) colectadas como restos de presas de F. peregrinus en sus áreas de nidificación, durante el periodo 2008-13. Todas las plumas de F. peregrinus contenían Hg (rango = 0.12-42.54 µg/g). La concentración total promedio de Hg en adultos fue significativamente mayor (12.19 µg/g) que la de individuos juveniles del año (3.76 µg/g). La concentración total promedio de Hg en individuos de F. peregrinus en ARNLM (adulto = 17.24 µg/g, pollo = 5.82 µg/g) fue significativamente mayor que en SNV (adulto = 2.7 µg/g, pollo = 0.67 µg/g) para ambas clases de edad. Entre los territorios de F. peregrinus, la concentración total promedio de Hg estuvo positivamente correlacionada con la proporción de aves acuáticas cazadas como presa (biomasa) y negativamente correlacionada con la distancia de los nidos al agua. Entre las presas, la concentración total promedio de Hg en aves acuáticas (5.07 µg/g) fue significativamente mayor que en aves terrestres (0.76 µg/g) y las especies que se alimentan de invertebrados acuáticos fueron el gremio de alimentación más contaminado (media = 6.17 µg/g). Podiceps nigricollis fue la especie presa con la concentración total promedio de Hg más elevada (12.27 µg/g). F. peregrinus, con su amplia distribución, amplio espectro trófico y uso de diversos tipos de hábitat, puede ser una especie indicadora ideal de la contaminación ambiental por Hg. Los estudios de contaminantes que incorporan el análisis de presas son útiles para determinar las vías de exposición y para evaluar los efectos ecológicos potenciales a través de una amplia variedad de tipos de hábitat. [ABSTRACT FROM AUTHOR]

The article focuses on the foraging behaviour of Northern Goshawks. It includes information on the diet of Goshawks, predation behaviour of Goshawks, and preying of ground squirrel. It also presents information on the raptor species for Goshawk's foraging including Cooper's Hawk, Ferruginous Hawks, and Harris's Hawks.

The article presents research which examined the factors that affect the presence of raptors in urban wildland. Topics covered include the impact of urbanization on native animals as well as abundance of prey in urban areas. Also mentioned is the sensitivity of raptors to changes in prey abundance as well as land covered by the species.

The article focuses on a study which examines the diet of Ural owls living in the forests of Mount Yatsugatake, central Japan, in the context of historic logging activities that have greatly extended the amount of open pasture and consequently modified small mammal availability in the region. Owl pellets from artificial nest boxes were used to analyze diet composition during the breeding season. Results revealed that the diet of Ural owls was dominated by wood mice, voles and shrew-moles.

The article presents a study which aims to analyze the effects of introduced species on raptors. The study used the ISI Web of Knowledge engine to look for articles regarding biological invasions concerning raptor species, wherein the analysis of variance (ANCOVA) was also applied. The study shows that 32% of 97 articles actually analyzed the relationship between raptors and introduced species excluding the articles which analyzes the effects of native species. The study also reveals that native raptors can be dependent on introduced species.

The article discusses a study aimed at characterizing the diet of the Magellanic Horned Owl in austral Patagonia, Argentina and comparing the findings with those previously reported for other regions. The study was conducted in austral Argentinean Patagonia, Santa Cruze province where the climate is cold temperature with a decreasing precipitation gradient from west to east and strong winds from the west. It references a study by Donazar et al which found high consumption of introduced hares and rabbits in the diet of the Magellanic Horned Owl in Patagonia, a result that was not repeated in subsequent studies in the same general area.

The article discusses a study on the diet of breeding Brown Falcons in and around the Canberra region during the breading seasons 2002-03 to 2005-06 and 2009-10. Twenty separate territories of Brown Falcons within 40 km. of the center of Canberra, Australia were sample with the Brown Falcon nests located in open, dry forest with adjacent grassy valleys typical of the preferred woodland habitat of said species. It indicates that for the sites samples, introduced rabbits were one of the more important food items for the Brown Falcon population and suggests a comparison of these dietary data to those of another woodland generalist raptor breeding in the same region, the Brown Goshawk.

The article focuses on a study about the niche separation of two sympatric owls in the desert of Northwestern China. In this study, the researchers compared the diets of Little Owls (Athene noctua) and Long-eared Owls (Asio otus) near the Minqin Desert Experimental Research Station. The study revealed the significant difference in their diets by frequency as well the difference in four dimensions. Based from the result of the study, it is concluded that the owls coexisted mainly by consuming prey of different size even if the roost sites of the two species were in close proximity.

A letter to the editor is presented about a behavior of a Golden Eagle dropping objects on or near potential prey items like Dusky Grouse observed the author at close range in Grasshopper Creek canyon on the Salmon-Challist National Forest in south-central Idaho.