Elanus Leucurus Research Articles

Hemoparasites identified in birds of prey in the mesoregion of Triangulo Mineiro, Minas Gerais, Brazil

Hemoparasitosis are common in birds of prey and cause changes in reproductive status and therefore susceptibility to predator attacks. This work evaluated the prevalence of hemoparasites in those birds in the region of Triangulo Mineiro, Brazil. Were analyzed 55 birds of the orders Accipitriformes (n=12), Falconiformes (n=11), Strigiformes (n=21) and Cathartiformes (n=11) allocated in Federal University of Uberlandia and Hospital Veterinário de Uberaba. Parasitological analyses were performed on the blood smear, confirming parasitism in 78,18% (43/55) of the animals. Accipitriformes showed statistically lower parasitism (33,3% - 4/12) than Falconiformes (90,9 – 10/11). Plasmodium spp. Infection was observed in 43 birds (78,18%), and one (2,32%) mixed infection with Babesia spp. and Plasmodium spp. No hemoparasites were observed in the species Elanus leucurus and Falco peregrinus. We conclude that the birds evaluated showed a high rate of parasitism by Plasmodium spp. and Caracara plancus had an unprecedented infection by Babesia spp. It suggested studies for identification, taxonomic and epidemiological.

Composite population trends reveal status of wintering diurnal raptors in the Northwestern USA

Integrated models can combine data from disparate monitoring programs to improve inference into population dynamics because trends in disparate datasets can be interpreted using a single index. We present a composite index of raptor population trends that combines data from two monitoring programs into a single estimate. The National Audubon Society's Christmas Bird Count and the East Cascade Audubon Society's Winter Raptor Survey use different methods to monitor the same populations of wintering raptors. Observers record all birds detected within 452 km2 ‘circles’ during the Christmas Bird Count, and during the Winter Raptor Survey observers count raptors along roadways. We present the results of a joint likelihood model that combines trends of raptors counted during both programs into a single population trend from 2005 to 2020. Population indices of the Bald Eagle (Haliaeetus leucocephalus), Ferruginous Hawk (Buteo regalis), Cooper's Hawk (Accipiter cooperii), Red-shouldered Hawk (Buteo lineatus), and Red-tailed Hawk (Buteo jamaicensis) increased over the course of our study, whereas Prairie Falcon (Falco mexicanus) and White-tailed Kite (Elanus leucurus) population indices declined. Further, the composite index for White-tailed Kite declined at a rate of 22 % (80 % CRI = 17 %–28 %) per year—supporting evidence of declines from breeding season surveys. We recommend further research into population trends of this species within its core California range. Our study advances efforts to combine trends in datasets collected using differing methodologies to estimate large-scale population trends from disparate data sets.

Peregrine Falcon Steals Prey from White-tailed Kites

Peregrine Falcon Steals Prey from White-tailed Kites

Microscopic Analysis of the Plumulaceous Feather Characteristics of Cathartiformes and Accipitriformes in North America

ABSTRACT Although variation in microscopic plumulaceous (downy) feather characters is known to be useful in taxonomic identifications of birds, the conserved characters unique to most avian orders remain understudied. We examined plumulaceous feather characters (morphometric and observed pigmentation patterns [qualitative]) within three avian families (Cathartidae, Pandionidae, Accipitridae) occurring in North America that often require taxonomic identification based on incomplete or fragmentary remains. We found significant quantitative differences among these three families for measurements of barbule length, node width, average number of nodes per barbule, and internode length. We observed additional differences in pigmentation patterns and spine distribution at nodes. Differences in pigment patterns and intensity are diagnostic for distinguishing Black Vulture (Coragyps atratus) from Turkey Vulture (Cathartes aura) within Cathartidae. Further observed differences of a higher percentage of spined structures present at node junctions along the length of barbules are diagnostic of Pandionidae. Within Accipitridae, pigmentation patterns and pigment intensity separate Swallow-tailed Kite (Elanoides forficatus) and White-tailed Kite (Elanus leucurus) from all other taxa; and barbule length, together with average nodes per barbule is unique to Northern Harrier (Circus hudsonius) in the families examined in this study. Although significant differences in a combination of microscopic feather characters among species were seldom observed in this study, family level differences were consistently documented. Results support the use of a suite of microscopic characters in combination with macroscopic feather features, geographic distributions, molecular methods, and other circumstantial evidence to aid in the identification of species of birds from feathers.

Breeding and diet of White-tailed Kites (Elanus leucurus) in the Texas panhandle

White-tailed Kites (Elanus leucurus) are grassland raptors that typically breed along coastal regions, particularly in California, southeastern Texas, and southern Florida. This species is irregular in the Texas panhandle, with few confirmed breeding and sighting records. We describe the first breeding record in Lubbock County, Texas, in which a pair of adults successfully raised 2 young in 2017 and may have returned and nested in 2018. Evaluation of cast pellets suggested dietary composition primarily consisted of diurnal rodents. Additionally, we compiled published and unpublished sighting and breeding records for the region and discovered reports for 2 nearby counties (Crosby and Kent counties, Texas) where White-tailed Kites have nested over multiple years, as well as several more counties with sighting records. Our data indicate that the southern extent of the Texas panhandle is now part of the species' breeding or “rare” range.

Reproductive behavior of White-tailed Kites (Elanus leucurus) in the Pampas of Argentina

The White-tailed Kite (Elanus leucurus) is a raptor that has been less studied in the Neotropics than in the Nearctic region, especially in relation to its reproductive behavior. In this study, we report information about the phenology and activity patterns of this raptor at the Pampas of Argentina. We found that White-tailed Kites have a prolonged breeding season, from October to May. Time-activity budgets of mating pairs indicated a pronounced division of roles in parental care between sexes. Females devoted most of their time to nest construction, incubation and chick care (80% of total time) and males to food provisioning and vigilance (70% of total time). We registered 11 cases of prey transfer from the male to the female. In four cases the transfer occurred in flight and in the remaining seven cases while individuals were perched. Our results agree with general patterns on breeding behavior of White-tailed Kites from North America, suggesting a consistent behavioral pattern throughout the species’ distribution.

Activity Budgets, Foraging Behavior, and Diet of White-Tailed Kites (Elanus leucurus) During Breeding and Nonbreeding Seasons In the Argentine Pampas

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.

Attempted kleptoparasitism of a White-tailed Kite by a Peregrine Falcon

Attempted kleptoparasitism of a White-tailed Kite by a Peregrine Falcon

Ampliación en la distribución geográfica y reproductiva del milano cola blanca Elanus leucurus en el centro-oriente de México.

Se reporta la distribución y reproducción del milano cola blanca Elanus leucurus en Puebla y Tlaxcala, confirmando su estatus de residente reproductor para Puebla, con nuevo registro para Tlaxcala.

Chipe encapuchado (Setophaga citrina) y otros registros notables de aves de Guerrero, México

Presentamos una lista de registros de distribución notable para 12 especies de aves en el estado de Guerrero, México, las cuáles observamos y colectamos durante el trabajo de campo llevado a cabo de 2006-2013 en diferentes ambientes del estado. Uno de los registros (Setophaga citrina) es nuevo para el estado, y otras cinco especies (e.g., Pelecanus erythrorynchos, Mycteria americana, Setophaga dominica) ampliaron su distribución geográfica a una provincia biótica donde su presencia no había sido previamente registrada. Confirmamos la presencia de otras seis especies (e.g., Elanus leucurus, Setophaga palmarum) con escasa información distribucional. Los registros presentados en esta nota científica muestran la importancia de continuar el trabajo de inventario en ambientes inexplorados e incluso en áreas que aparentemente están bien documentadas. Este tipo de información junto con estudios sobre la biogeografía, taxonomía y ecología, ayudarán a comprender mejor la historia natural de las aves y su conservación.

Trophic ecology of two raptors, Barn Owl (Tyto alba) and White-tailed Kite (Elanus leucurus), and possible implications for biological control of Hantavirus reservoir in Chile

ABSTRACT Raptors are important predators of various species of small mammals, which renders them of economic importance since their prey may be either disease vectors or reservoirs which represent health problems, or economically important through the damage they cause to crops and stocks. The long-tailed rice rat Oligoryzomys longicaudatus is a reservoir and vector of Hantavirus, a disease of increasing importance in various Latin American countries. The nocturnal Barn Owl (Tyto alba) and the diurnal White-tailed Kite (Elanus leucurus) appear to be the most significant predators of this species. Here, we characterize the diet of these two raptors and analyze their trophic specialization and dietary selectivity using published information, pellet analysis, and field abundances of small mammals. Both raptor species positively selected O. longicaudatus in their diets to suggest that they could be potential controllers of the Hantavirus reservoir in Chile, both in natural and agricultural ecosystems. Predati...

Taphonomic analysis of rodent bone accumulations produced by the White-tailed Kite (Elanus leucurus, Accipitriformes) in Central Argentina

The main objective of this study was to determine the taphonomic characteristics of ingested rodent prey remains recovered from White-tailed Kite (Elanus leucurus, Accipitriformes) pellets. Bones were analyzed in order to identify taphonomic features produced by this predator. Sampling was performed during the austral reproductive season of 2011 in Central Argentina (La Pampa province). The taphonomic variables evaluated suggest that E. leucurus produces strong digestion (categories 4–5). Results and interpretations were compared with results provided by samples from the Black-shouldered Kite, Elanus caeruleus, in Algelia, and from other Falconiformes and Accipitriformes species. The dietary similarity of E. leucurus and Barn Owl (Tyto alba, Strigiformes), suggests that both raptors are dietary counterparts, consuming the same trophic resources alternatively during day and night, but overlapping in their diets. In this context, the role of E. leucurus as fossil or archaeological bone accumulators or as an agent involved on the formation of the deposit might introduce an equifinality problem. The results presented here can be used as an analytical model for the interpretation of the micromammal fossil record from paleontological and archaeological sites.

Temporal Fluctuations in Raptor Abundances in Grasslands of Southeastern South America

Abstract We conducted 44 roadside surveys on grasslands landscapes of southern Brazil and Uruguay to study temporal changes in raptor abundance. Each route was surveyed twice in fall/winter and twice in spring/summer. Raptor abundance was higher during summer than winter, but did not differ between years. Thirteen of the 33 species recorded showed temporal changes in abundance, or are known to be migrants in the region. White-tailed Kite (Elanus leucurus), Yellow-headed Caracara (Milvago chimachima) and Southern Caracara (Caracara plancus) had higher abundance during fall/winter than spring/summer, which might be attributed to nomadic movements in agricultural landscapes. Changes in abundance of Savanna Hawk (Buteogallus meridionalis) and American Kestrel (Falco sparverius) suggest irruptive or nomadic movements. Turkey Vulture (Cathartes aura), Snail Kite (Rostrhamus sociabilis) and White-tailed Hawk (Geranoaetus albicaudatus) were more abundant in spring/summer than fall/winter, and our results suggest ...

Agonistic interactions in raptors of the Pampas region

Abstract In this study, we evaluated the interspecific agonistic responses of raptors and non-raptors, elicited by the presence of five raptor species (Circus cinereus, C. buffoni, Rupornis magnirostris, Elanus leucurus, and Geranoaetus melanoleucus) in the Pampas region of Argentina. We registered 62 agonistic interaction events, most of them involving two raptor species (58%). During these events we registered 122 attacks, 10 persecutions, and three cases of kleptoparasitism. Milvago chimango was the most important aggressor species among raptors, and Vanellus chilensis among non-raptor birds. Attacks in groups were more frequently performed by non-raptors (61.5% of the events involved two or more aggressor individuals) than by raptors (68.5% of the events involved only one aggressor). This study represents a primary approach to one scarcely explored aspect of raptor behavior in southern South America.

Aves, Bosque Oriental de Bogotá Protective Forest Reserve, Bogotá, D.C., Colombia

Baseline information is a priority for conservation plans of protected areas, especially when they are of great importance for the maintenance of biodiversity. However, many nature reserves are lacking this information. Here I present a characterization of the avifauna studied along the La Agüadora - San Rafael trail in the Bosque Oriental de Bogotá Protective Forest Reserve. I recorded 67 species after 18 visits done to the study area. The species accumulation curve indicates that the survey was not sufficient, but noteworthy records for Elanus leucurus (Vieillot, 1818), Megascops albogularis (Cassin, 1848), Ciccaba albitaris (Bonaparte, 1850), Caprimulgus longirostris (Sclater, 1866), Synallaxis subpudica Sclater, 1874, Catamenia inornata Berlepsch, 1885 and Atlapetes pallidinucha (Boissoneau, 1840) were obtained. Information provided can be useful for future management plans especially when considering spatial heterogeneity as a key base concept.

Communal Roosting Behavior and Winter Diet of the White-Tailed Kite (Elanus leucurus) in An Agricultural Habitat on the Argentine Pampas

Although the White-tailed Kite (Elanus leucurus) is widely distributed throughout the Americas, winter communal roosting has been recorded only in the Nearctic portion of its range. As a result, data on the food habits of the White-tailed Kite in South America during the nonbreeding season are scarce and, when available, limited to pellets from solitary individuals. Here, we report the communal roosting behavior and the winter diet of White-tailed Kites in an agricultural habitat on the Argentine pampas based on information gathered over three consecutive years (2006–2008). From May to July of each year, we observed an average of 11 (±SD = 2.8) kites roosting in a grove of Eucalyptus viminalis. Prior to roosting, kites gathered in a tall, dead, and leafless Eucalyptus tree before flying to more densely foliated trees where they spent the night. The diet of kites during winter was composed almost entirely of small mammals, mainly Calomys sp. and Akodon azarae. Because agricultural intensification in the Argentine pampas is ongoing, further studies are needed to gain a complete knowledge of White-tailed Kites in this habitat and of the effects of land-use changes on their foraging and other behavior.

Seasonal Variation in the Diet of the White-Tailed Kite (Elanus leucurus) in A Suburban Area of Southern Chile

Abstract In 2004–05, we evaluated seasonal variation in the diet of White-tailed Kites in a suburban area of Concepcion, southern Chile. Kites' diet was determined based on pellets (N = 209) and consisted of rodents, insects and birds (95.6%, 13.8% and 0.6% of all consumed individual prey [N = 343]). Olivaceous field mice (Abrothrix olivaceus) and long-haired mice (A. longipilis) were the most common prey (47.5% and 32.4% of all prey by frequency, respectively; 40.3% and 38.9% by biomass, respectively). Rodents were important in the diet in all seasons (frequency = 88.6–100%, biomass = 98.8–100%), and the ranking of rodent prey species in the diet was virtually the same for all seasons (χ2 = 4.6, P > 0.05). The geometric mean weight of vertebrate prey was also similar among seasons (27.0–28.6 g). The frequency of rodent prey species in the pellets was positively correlated to rodent prey abundance in the environment, as measured using live-trapping surveys (rs = 0.83, P < 0.05). Our results co...

Habitat associations of small mammals in southern Brazil and use of regurgitated pellets of birds of prey for inventorying a local fauna

We inventoried terrestrial small mammals in an agricultural area in southern Brazil by using trapping and prey consumed by Barn Owls (Tyto alba) and White-tailed Kites (Elanus leucurus). Small mammals were trapped in three habitat types: corn fields, uncultivated fields ("capoeiras"), and native forest fragments. A total of 1,975 small mammal specimens were trapped, another 2,062 identified from the diet of Barn Owls, and 2,066 from the diet of White-tailed Kites. Both trapping and prey in the predators' diet yielded 18 small mammal species: three marsupials (Didelphis albiventris, Gracilinanus agilis, and Monodelphis dimidiata) and 15 rodents (Akodon paranaensis, Bruceppatersonius iheringi, Calomys sp., Cavia aperea, Euryzygomatomys spinosus, Holochilus brasiliensis, Mus musculus, Necromys lasiurus, Nectomys squamipes, Oligoryzomys nigripes, Oryzomys angouya, Oxymycterus sp.1, Oxymycterus sp.2, Rattus norvegicus, and Rattus rattus (Linnaeus, 1758)). The greatest richness was found in the uncultivated habitat. We concluded that the three methods studied for inventorying small mammals (prey in the diet of Barn Owls, White-tailed Kites, and trapping) were complementary, since together, rather than separately, they produced a better picture of local richness.

Comparison of food habits and prey selection of the white‐tailed kite, Elanus leucurus, between natural and disturbed areas in central Argentina

We studied the food habits of white‐tailed kites (Elanus leucurus, Accipitridae) in central Argentina during austral spring and summer (November to March) and compared prey captured in two different habitat types. Diet was determined by analysing pellets and prey remains collected under nests and roost sites. During the same period small mammals were trapped using pit‐fall traps in Parque Luro reserve with the aim of assessing prey selection by kites. In Parque Luro reserve (semiarid forest), tuco‐tucos (Ctenomys sp., Rodentia) were the main prey in the white‐tailed kite diet, accounting for 75% of the items and 91% of biomass. In agricultural fields, however, there was not a single main prey species, as measured either by number of prey items or by biomass, Calomys sp. (43%) and Akodon azarae (22%) being the main prey in this habitat. The analysis of prey availability in the Parque Luro reserve showed that tuco‐tucos are a seasonally available prey, only captured in spring and summer. During these seasons, the consumption of tuco‐tucos by white‐tailed kites was disproportionately higher than the occurrence of tuco‐tucos, indicating a preference for this species by kites. These results suggest that other prey attributes, such as conspicuousness and social behavior, could be key factors in prey selection by white‐tailed kites.

SIGNS OF PARENTAL BEHAVIOR IN LIOLAEMUS ELONGATUS (SAURIA: LIOLAEMIDAE) OF NEUQUÉN, ARGENTINA

Abstract Parental care in reptiles has been correlated with cold climates and harsh environments. We investigated whether behavioral patterns indicating parental care occurred in the lizard, Liolaemus elongatus, a viviparous species found on rocky outcrops of the Argentinean Patagonia. Five pregnant females were captured during the austral summer and brought to the laboratory for observations. The females were filmed for short periods of time during six days after the birth of their young. During that time, the mothers and offspring were presented with three predatory stimuli, a Diplolaemus sexcinctus, a male Liolaemus elongatus, and a stuffed hawk, Elanus leucurus. Their responses were recorded as well as the distance between mothers and offspring during the experiments and when no stimuli were presented. Except for one female, mothers constructed burrows in which the neonates were born. Mothers and their offspring occupied the same shelter for the whole period of observation. When presented with predato...