No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Water Reservoirs and Power Lines as Mortality Sources for Crested Caracaras
Este artículo no cuenta con un resumen.
There is a paucity of data evaluating water use by raptors. Although raptors are believed to satisfy their water requirements through metabolic processes, they are known to experience reduced reproductive success during periods of drought, and there is evidence of water being important for site occupancy in arid landscapes. Several raptor species have a seasonal or year-round presence in west Texas, a drought-prone, semi-arid region of the Southern Great Plains. We examined species-specific timing of free water use by common raptors in this region, and examined environmental conditions associated with water use. We collected 4549 camera trap-days of data across 4 yr at ten human-made water sources placed for cattle. We recorded 14 species of raptors among the 1177 detections of raptors visiting water sources; of these, 1084 raptors (92.1%) perched at tanks, and 93 (7.1%) flew by tanks. Of the raptors that perched at tanks, 63.5% drank and 20.8% both bathed and drank. Barn Owls (Tyto alba; 35.6%), Swainson's Hawks (Buteo swainsoni; 32.0%), and Northern Harriers (Circus hudsonius; 21.0%) were the predominate species detected. Visits by Northern Harriers and Swainson's Hawks increased with increasing temperature and decreasing precipitation. Visits by Barn Owls increased with increasing drought severity. Further, detections per 100 trap-days increased substantively across our 4-yr study period during which the region experienced one of the worst droughts on record. Although our data do not demonstrate these raptors require free water, they do reveal an increasing use of free water in relation to hotter and drier conditions. How this influences survival and reproduction remains unknown, but may become a pressing question because current climate models predict the study area will experience increases in heat and decreases in precipitation.
Power lines endanger birds around the world, as a large number of them are killed every year through electrocutions and collisions. This problem can have severe consequences at population level, particularly for threatened species. While this threat has been widely studied in different parts of the world, information from South America is scarce. Here, we review information from scientific and grey literature on the collision and electrocution of birds on power lines from this sub-continent. We complement this information with novel data provided by a citizen science project, electrical companies and field monitoring records. Our results show that although in South America scientific and anecdotal information on this topic is scarce, data suggests that this threat is present in many areas of this sub-continent and affects several species, some of which are seriously threatened. However, information on the most affected species, the number of individuals impacted, the most dangerous geographical areas and the effectiveness of mitigation action is scarce and mainly anecdotal. This is worrying, because South America is a hot spot of biodiversity with many threatened and endemic bird species. We urge conservationists to evaluate this problem in more detail, define areas where it is important to avoid power line installation and establish priority areas for implementation of effective mitigation actions. Scientific evidence shows that dangerous power lines require retrofitting, but this knowledge should also be applied to the new energy facilities and the establishment of national regulations, which would undoubtedly reduce the impact of this infrastructure on wildlife.
La muerte por ahogamiento de loicas pampeanas en reservorios de agua para uso
ganadero representa una amenaza adicional para la conservación de esta especie, cuyo impacto no ha sido debidamente abordado hasta el momento. Presentamos aquí observaciones preliminares sobre una experiencia de utilización de dispositivos de flotación en este tipo de reservorios para evitar el ahogamiento de individuos de esta especie amenazada en el sudoeste de la provincia de Buenos Aires, Argentina. Se analizan situaciones observadas de baja efectividad y medidas para mejorar su eficiencia. La utilización de estos dispositivos mitiga la mortalidad de loicas pampeanas en los reservorios de agua sirviendo, además, como herramientas económicas, fáciles de colocar y beneficiosas, tanto para la producción agropecuaria, como para la fauna silvestre en general.
Aim
Migratory species rely on multiple ranges across the annual cycle, rendering them vulnerable to a wide range of spatially disparate anthropogenic threats. The spatial distribution of these threats will strongly influence the magnitude of their population‐scale effects, but this has not been quantitatively assessed for most species.
Location
Europe, Central Asia, Western Asia, Africa.
Time period
Modern.
Major taxa studied
Aves.
Methods
We combined remote‐sensed data and expert opinion to map 16 anthropogenic threats relevant to migratory birds across Europe, Africa and the Middle East – including the first spatially‐explicit pan‐continental assessment of relative hunting pressure. By combining the resulting composite threat maps with species range polygons and morpho‐behavioural traits‐based weightings (reflecting relative threat susceptibility), we created species‐specific risk maps for 103 Afro‐Palaearctic migratory birds breeding in Europe and evaluated how spatial threat vulnerability relates to long‐term population trends.
Results
We found that greater vulnerability to direct mortality threats (including hunting pressure, infrastructure and nocturnal lights), especially in the non‐breeding season, is associated with declining bird population trends.
Main conclusions
Our results emphasize the importance of spatially explicit approaches to quantifying anthropogenic drivers of population declines. Composite risk maps represent a valuable resource for spatial analyses of anthropogenic threats to migratory birds, allowing for targeted conservation actions.
We searched for nests and studied aspects of the breeding biology of Southern Caracaras (Caracara plancus) in the Patagonian grasslands biome of southern Santa Cruz province, Patagonia, Argentina, at the southern limit of the species' continental distribution. In this open, mostly flat landscape where potential nest substrates are rare and isolated yet conspicuous, caracaras nested in native Magellan barberry shrubs (Berberis microphylla), exotic trees associated with ranch houses and other buildings, on coastal cliffs, and on human-made structures associated with petroleum and gas extraction plants. These extraction activities, which began only in the past three decades in this region have provided new nesting opportunities for this species. Nest characteristics, brood size, and productivity recorded in our study area were similar to what has been previously reported for the Southern Caracara nesting across its broad latitudinal range. In our study area, average productivity in both years combined (2010–2011) was 2.1 fledglings per successful pair (n = 27). The nesting season for this caracara population apparently extends from September through January, phenology that is similar to that reported for caracaras nesting at a similar latitude in Chile and for other raptor species in Santa Cruz province. However, the nesting season seems to be shorter than for caracara populations nesting at northern latitudes in Argentina. In this vast, open landscape, nest substrates provided by human-made structures may be an important determinant of the spatial distribution of Southern Caracara nests.
RESUMEN. En este trabajo se presentan nuevos aportes y se recopila la información existente, acerca de la nidificación de aves de presa diurnas (Falconiformes) en estructuras humanas en la Argentina. Al presente, son catorce especies las que utilizan sustratos artificiales en el mencionado país. Diez emplean postes de tendido eléctrico. Halcones Peregrinos (Falco peregrinus), Jotes Cabeza Negra (Coragyps atratus), Milanos Blancos (Elanus leucurus) y Águilas Coronadas (Buteogallus coronatus) no han sido descriptas nidificando en tendidos eléctricos pero si en otro tipo de construcciones. Caranchos (Caracara plancus), Chimangos (Milvago chimango) y Halconcitos Colorados (Falco sparverius) serían las únicas especies que además de postes de electricidad emplean otros sustratos. El conocimiento, aún muy limitado en Sudamérica, acerca de las estructuras construi-das por humanos utilizadas por las distintas especies para nidificar, se considera relevante para el manejo y conservación de las mimas. ABSTRACT. RAPTORS THAT NEST ON MAN-MADE STRUCTURES IN ARGENTINA. NEW RECORDS AND A REVIEW. In this paper we compile information (a review and new data) about the nesting of diurnal birds or prey (Falconiformes) on man-made structures in Argentina. At present, fourteen species use artificial substrates. Ten species use electricity pylons. Peregrine Falcons (Falco peregrinus), Black Vultures (Coragyps atratus), White-Tailed Kites (Elanus leu-curus) and Crowned Eagles (Buteogallus coronatus) have been described nesting on artificial substrates but not on electricity power lines. South American Caracaras (Caracara plancus), Chimango Caracaras (Milvago chimango) and American Kestrels (Falco sparverius) seem to be the only species capable of nesting on pylons and on other types of human made structures. The knowledge, by the way very limited in South America, about the artificial manmade structures used by the different species/ populations of birds of prey is considered an essential tool for their management and conservation.
Several species of birds, including raptors, add man-made objects, stones, green
plants, skins and dung of animals to build and decorate their nests. However, there is a
compromise between the use of new nesting material and the increased risk of nestling
mortality due to entanglement or ingestion of debris. Here, we observed the decoration
in 74 of 77 (96.10%) nests of Southern Caracara (Caracara plancus) in an agricultural
area of La Pampa province. Caracaras mainly incorporated agricultural twine in their
nests and nestlings sometimes got entangled and died. We found 2 occurrences of
entanglement during nine years of study. Decorating the nest, or at least to lean its
interior with nylon twine, can impose a relevant death toll to Southern Caracaras, as
has been found in other species elsewhere. Extension campaigns to reduce the
misuse and the final disposal of debris materials such as baling twine in agricultural
landscapes will be required to reduce this anthropic source of mortality in a species
that although still common, is apparently reducing its numbers with the expansion of
intensive agriculture.
Anthropogenic mortality has a considerable impact on populations of long-lived species, such as raptors, which increasingly inhabit human-dominated landscapes. Here, we analyzed long-term mortality data for two rapidly declining owls, Little Owl Athene noctua and Barn Owl Tyto alba, in the Czech Republic. We evaluated relative mortality rates with respect to owl age, month of carcass recovery, and two time periods (before and after year 2000). We examined 961 mortality records (199 Little Owls and 762 Barn Owls) derived from six distinct database sources totally spanning the period of years 1934–2017 and the entire Czech Republic. Natural causes, entrapment in vertical hollow objects and drowning in liquid reservoirs (entrapment), and collision with vehicles accounted for the highest proportion of mortality cases in Little Owl, while collision with vehicles and entrapment represented the most important mortality sources in Barn Owl. Relative mortality rates in Little Owl caused by entrapment, non-vehicle collision, electrocution at power lines and confinement in buildings increased after the year 2000. In turn, the relative mortality rate due to collision with vehicles increased after 2000 in Barn Owl. Persecution, collision with vehicles, and entrapment accounted for higher relative mortality rates in first-year than adult Little Owls. In Barn Owls, higher relative mortality rates due to collision with vehicles and entrapment were detected in adult compared to first-year birds. Finally, relative mortality rates differed between age classes according to the month of carcass recovery for both species. For Little Owl, the highest relative mortality rates in first-year individuals were detected during July and September, whereas adult Little Owls suffered the highest relative mortality rates during March, November and December. In Barn Owls, the relative mortality rates of first-year individuals peaked in November and December, whereas adult birds suffered the highest relative mortality rate during July, January and February. This study strongly suggests that reducing the risk of anthropogenic mortality may be crucial to halt the decline of Little Owl and Barn Owl populations.
High mortality by electrocution has been suggested to be the main factor behind the reduction of several birds of prey populations across the world. Almost nothing is known, however, about the impact of power lines on this group of birds in the Neotropical Region. Here we estimate electrocution rates for birds on power lines covering both arid and semiarid biomes of central Argentina. We conducted six bi-monthly power line and raptor surveys throughout 355 km of lines and roads covering an area of approximately 12,000 km ² . We described the structural design of 3,118 surveyed electricity pylons. We found 34 electrocuted individuals of four bird families that constitute an annual bird electrocution rate of 0.011 bird/pylon/year. Bird electrocution occurred mostly on concrete pylons with jumpers above the cross-arm. Larger birds of prey had a higher electrocution rate than smaller species. The Crowned Solitary Eagle Buteogallus coronatus was disproportionately affected by this mortality source when compared with its low population density. Electrocution incidents occurred mostly in a few electric pylon designs that represent only 10.2 % of the power pylons monitored in the study area. Therefore, the change or modification of a small fraction of pylons would almost eliminate bird electrocution incidents in our study area. Our results prove that electrocution is a relevant cause of mortality for Crowned Solitary Eagles and urgent mitigating actions are needed to reduce this mortality factor.
RESUMEN. Se estudió la biología reproductiva del Carancho (Caracara plancus) en los alrededores de Villa María, Córdoba, Argentina. El Carancho construyó sus nidos en árboles de buenos portes tanto autóctonos como exóticos, entre los 4,5 y 11 m de altura. La postura fue de 3 a 4 huevos, los mismos son puestos en días alternados. El período de incubación fue de 30 a 31 días. Los pichones fueron alimentados por ambos miembros de la pareja y permanecieron en el nido de 48 a 52 días. La temporada de cría ocurrió entre junio y diciembre.
Caracara cheriway (Crested Caracara) typically nest in Sabal palmetto (Cabbage Palms) in Florida and isolated thorny shrubs (e.g., Celtis pallida [Granjeno]) in Texas. The species has not previously been reported to use anthropogenic nest substrates. We found Crested Caracara nests in an electrical substation, on a radio tower, and on a billboard near Clewiston, FL, and in an electrical substation and on a lattice electrical-transmission tower near Houston, TX. Our observations of nesting on anthropogenic substrates may support 3 distinctly different inferences. First, the behavior could be ongoing but not previously reported. Second, because individual Crested Caracaras in breeding plumage persist for years as floaters, novel use of anthropogenic nest substrates may indicate adult Caracaras seeking any possible nesting opportunity, even if nest success is low. Third, Crested Caracaras may be modifying their breeding behavior to capitalize on high-quality resources in areas that lack traditional nest substrates. Comparison of productivity between nests on anthropogenic and natural substrates would resolve the latter 2 competing hypotheses. Because management focuses primarily on nest sites, novel nesting-behavior could have important management implications. Future research should quantify productivity on anthropogenic substrates and document whether individuals produced at these sites tend to return to anthropogenic substrates to breed.
Crested Caracaras (Caracara plancus) range from the southern United States to southern South America and, although the natural history of North American popula-tions has been described (Bent 1938, Brown and Ama-don 1968, Morrison 1996), there has been little in-depth study of the species elsewhere. Nest characteristics for Crested Caracaras have been documented in Baja Cali-fornia (Rivera-Rodriguez and Rodriguez-Estrella 1998), Texas (Dickinson and Arnold 1996), Florida (Morrison 1996), and Argentine Patagonia (Travaini et al. 1994). Knowledge of the Argentine population is limited to Tra-vaxni et al. (1994) and several brief notes. In this paper, I describe characteristics of 17 Crested Caracara nests found during December 1998 and January 1999 in north-ern La Pampa, Argentina, and compare these character-istics with those observed in other populations. STUDY AREA The landscape in the northern La Pampa panhandle (approximately 35ø14'S, 63ø57'W) is dominated by a mix of cattle ranching and row-crop agriculture. Common summer crops are alfalfa, sunflower, sorghum, and corn. Uncommon and isolated native mesquite (Prosopis spp.) trees and introduced Chinese elm (Ulmus parvifolia) are found along dirt and paved roads. Mesquite trees in fields have generally been removed for agriculture and few remain. Forested areas are generally groves of intro-duced eucalyptus (Eucalyptus spp.) trees, planted as shade areas for cattle, for wind breaks between fields, and as entrance corridors to estate houses. High winds and strong rains are common during the summer, particularly from the southeast. Annual rainfall is 828 mm, with 50% occurring from November through February. Summer temperatures range from 23-38øC. METHODS Surveys for caracara nests were conducted by vehicle • n December 1998 and January 1999. Surveys were con-ducted once, over approximately 420 km along a 2000 km 2 grid of public dirt and paved roads. Roads were buff-ered by 10 m of public land on each side, were fenced, and lay adjacent to private ranches. Private lands were not surveyed. All trees and shrubs along the roads were checked for caracara nests. Nests showing disrepair or no sign of occupancy during the breeding season were not • Present address: Mendocino Redwood Company, P.O.
Many birds do not breed in the year(s) immediately following independence from parental care. Instead, they spend time as immatures attaining adult plumage and spend time as floaters searching for an opportunity to breed. Floaters are nonbreeding adults. Survival during this period often is poorly understood because immatures and floaters can be secretive and range widely, making them difficult to track. From July 2006 through March 2009, we used radio-tracking data collected by aerial telemetry to estimate survival of 58 nonbreeding Crested Caracaras (Caracara cheriway). Based on an information-theoretic approach, the best-supported models indicated differences in monthly survival, which was lowest (0.953) during the peak of breeding (December–January), slightly higher (0.984) during the remainder of the breeding season (October, November, February, March), and highest (0.995) during the nonbreeding season (April–September). We identified “life stage” as juvenile, immature, or floater on the basis of plumage. We found no effect of sex or life stage on monthly or annual survival, and annual survival was intermediate (0.826) between existing estimates for breeding caracaras (0.876 for males and 0.906 for females) and the dependent juveniles (0.694) of breeding caracaras. None of the birds we tracked nested during our 33-month study. Our findings provide unique insight into reduced survival of nonbreeding individuals during the period when the remainder of the population breeds, and the long-term persistence of individual floaters supports the assertion of previous authors that all breeding habitat is occupied.
Durante oct 1992 se realizaron conteos en carrtera de rapces a lo largo de 2230 km., en una región central de la Argentina. Fueron detectadas 16 (80%) de las 20 especies presentes (incluyendo jotes9. La especie más común fué el chimango Milvago chimango (397), seguida del gavilán caracolero Rostrhamus sociabilis (191), y del carancho Polyborus plancus (66). La abundancia del chimango parece estar relacionada positivamente con el nivel de alteración humana del ambiente, alcanzando valores máximos en las afueras del la ciudad de Buenos Aires. La diversidad de rapaces fua máxima en zonas arbustivas y estepas de la Pampa seca y el n. de la Patagonia.
Background: Raptor distributions and abundances are poorly known in southern Brazil. Given that raptors have low population densities, methods typically applied to census birds are usually inappropriate for surveying raptors. Roadside surveys allow large areas to be searched at a relatively low cost and are often applied to count raptors. We conducted eight paired roadside surveys (roadside point transects and roadside strip transects of 54.5 ~ 58.6 km long) to assess the species richness and abundance of raptors in two grassland landscapes of southern Brazil and to compare results of the two methods. Results: In total, 1,890 observations of 18 raptor species (118.13 individuals (ind.)/transect) were recorded. Raptor abundances were higher in the altitudinal grasslands (299.25 ± 48.91 ind./transect) than in the coastal plain (86.63 ± 44.04 ind./transect). Abundances were higher when raptors were surveyed with point transects (9.38 ind. · [10 km 2 ] −1 · h −1) than with strip transects (3.55 ind. · [10 km 2 ] −1 · h −1). No significant differences were found in relation to species richness, although five species were exclusively recorded with point transects versus one with strip transects. Conclusions: Roadside point transects may reduce bias due to differences in species detection caused by habitat features and in abundance estimates resulting from survey habitat being disproportional to their availability. Point counts may enhance the quality of the search for raptors in a surveyed area, increasing the detection probability. The choice of survey method depends on the objectives of the study, but our results favor the use of point transects rather than strip transects to survey raptors in open landscapes.
We evaluated the relationship between an assemblage of diurnal raptors and local- and landscape-scale habitat variables in the eastern portion of South America's temperate grasslands in Argentina (37 degrees 32'-37 degrees 45'S, 57 degrees 19'-57 degrees 26'W). The landscape is a mosaic of agroecosystems and natural grasslands. Raptor species were sampled using fixed-distance point-counts, from October 2004 to February 2005. We used generalised additive models to analyse the relationship between raptor occurrence or abundance and environmental predictors at two spatial scales: local (at plot level) and landscape (areas of 25 and 100 km(2) around the survey points). At local scales we measured vegetation height and percentage cover. Landscape-scale variables included percentage of each habitat type, landscape diversity, and fractal dimension. Higher values of species richness were recorded in landscapes with a complex matrix of disturbed and undisturbed plots. The abundance of Chimango Caracara (Milvago chimango) was positively associated with roads, sites with a complex matrix of disturbed and undisturbed plots, and high levels of forest cover. The presence of Long-winged Harrier (Circus buffoni) increased in landscapes dominated by natural habitats, mainly natural grasslands. The presence of Southern Crested Caracara (Caracara plancus) increased mostly in plots with high amounts of short grass cover and away from roads. Based on our results, we suggest that maintenance patches of natural grassland is essential for the preservation of ground-nesting species, and preservation of habitat diversity would ensure that most of the raptor species in the assemblage had their ecological requirements met.
En las Islas Malvinas, las rapaces han sido percibidas históricamente como una amenaza para el ganado y consecuentemente han sido ampliamente perseguidas durante la mitad del siglo veinte. Las medidas de conservación han minimizado la persecución permitiendo el aumentos de las poblaciones de rapaces, pero su ecología en las Islas Malvinas permanece poco conocida. Investigamos las jerarquías sociales dentro de un ensamble de rapaces carroñeras no migratorias: Buteo polyosoma, Phalcoboenus australis, Caracara plancus y Cathartes aura jota. Durante treinta secciones de observación de 30 min cada una, registramos 1386 interacciones agresivas involucrando una o más de estas especies. Encontramos que los individuos de B. polyosoma fueron agresores en 98% (95% IC = 96–100%) de las interacciones con P. australis, 82% (69–95%) de las interacciones con C. aura y 80% (72–88%) de las interacciones con C. plancus. Los individuos de C. plancus fueron agresores en 100% de las interacciones con P. australis y 90% (80–100%) de las interacciones con C. aura. Los individuos de C. aura fueron agresores en 71% (61–82%) de las interacciones con P. australis. En cada especies, encontramos que los adultos de C. plancus fueron agresores en 78% (72–84%) de las interacciones con los juveniles coespecíficos y 76% (68–85%) de las interacciones con los subadultos coespecíficos. Los adultos de P. australis fueron agresores en 100% de las interacciones con los juveniles coespecíficos y 97% (91–100%) de las interacciones con los subadultos coespecíficos. Los patrones predichos de dominancia basados en el tamaño, típicos de los ensambles complejos de aves carroñeras de África y Sud América no fueron observados en los ensambles relativamente simples de las Islas Malvinas, pero observamos grupos de una sola especie de hasta 83 individuos de C. plancus y 42 individuos de P. australis.
a b s t r a c t Population growth and human development result in biodiversity loss and biological homogenization not only in developed countries, but increasingly in the less developed countries as well. In those countries, where urbanization and agricultural intensification occur at a faster rate than in developed countries, habitat degradation appears to be the leading cause of wildlife loss. During the breeding seasons of 2002–2005 we conducted road surveys across five biomes of Argentina to detect variations in raptor community attributes as potential indicators of broad scale habitat degradation. Abundance of individu-als, richness and diversity of species were calculated to assess the effects of habitat transformation and patch size on these community attributes. Raptor communities strongly varied in relation to habitat transformations, with lower abundance of individuals, richness and diversity of species in more trans-formed landscapes. Small patches of natural vegetation and locations in which natural and cultivated lands where interspersed showed lower richness and diversity of raptors than large patches. Fragmenta-tion was the main cause of reductions in abundance of individuals. Although the relative contribution of our two estimates of habitat degradation to abundance, richness and diversity of raptors varied among biomes, these community attributes proved useful as predictors of habitat degradation. This was espe-cially true in habitats where raptor communities are more complex although overall patterns remained constant across biomes, from forests to deserts. Taking into account current trends of habitat transforma-tion (drastic increments in monocultures, urban areas, and habitat patchiness), the conservation of raptor communities in these biomes could be seriously compromised. In terms of species-specific responses of raptors to habitat degradation, a rapid process of homogenization can be expected, resulting in only a few winner species within a general scenario of losers.
Electrocutions and collisions of birds with power lines have long represented an important worldwide conservation issue. Raptors such as eagles are susceptible to electrocution on distribution power lines because they are large birds and because certain species frequently perch or nest on power poles. Electrocution is an important cause of population declines among a number of sensitive raptor species. Electrocution risk is distributed unevenly among poles; for any pole, electrocution risk is a function of pole hazard (spacing between energized and grounded components) and exposure (pole utilization) by susceptible species. Habitat, sex, age, weather, and behavioral factors also play an important role in electrocution. Electrocution risk can be successfully mitigated by increasing separation between hazardous contacts, adding insulation, or attempting to redirect birds to safer locations. Statistical models are useful for identifying high risk poles, where mitigation can provide maximum conservation benefit. Raptor collisions with power lines also have been documented globally, and may involve sensitive species. Raptor collision risk appears to be elevated where lines bisect travel corridors, particularly when individuals are distracted by courtship, territorial defense, or hunting, or visibility is reduced by weather or low light. Collision can be reduced using devices increasing line visibility. Although numerous methods for reducing or eliminating electrocutions and collisions have been developed, published, and successfully implemented, raptor electrocutions and collisions persist. This chapter addresses common problems and solutions associated with raptor electrocutions and collisions.
The breeding biology of the Crested Caracara (Caracara plancus) was studied during the 1990 and 1991 breeding seasons in Baja California Sur, Mexico. Sixteen nests were monitored in 1990 and six in 1991. The breeding season extended from February-August. Caracaras were more abundant during the post-fledging period (October-November) when up to 1.2 birds/km were registered in road surveys. The cardon cactus (Pachycereus pringlei) was the most used structure for nesting (76% of nests), although other tree-like structures were also used. Nest material consisted mainly of twigs of rama parda (Ruellia peninsularis), coralvine (Antigonon leptopus), and condalia (Condalia globosa). Nesting success estimated using the Mayfield method was 0.75 and 0.38 in 1990 and 1991, respectively. Mean (±SD) productivity was 2.2 ± 0.4 and 1.8 ± 0.7 fledglings per successful nest in 1990 and 1991, respectively. Five second clutches were registered. The productivity of the Cape region Crested Caracara population was similar to that reported for caracaras in Texas but higher than in Arizona.
To evaluate the status of Florida's threatened Crested Caracara (Caracara cheriway) population, knowledge of life history parameters and population dynamics is required. Using the program MARK, I estimated survival rates for adult and juvenile Crested Caracaras from breeding areas in southcentral Florida during the period February 1994 through March 2000. Annual adult survival probabilities estimated from resightings of banded individuals and derived using model averaging were 0.876 for males and 0.906 for females. Results of modeling monthly juvenile caracara survival from radiotelemetry data identified differences in survival for two age groups: juveniles (up to age 3 years) and adults (age >3 years). Using this age-effects model, monthly survival for juvenile caracaras was estimated to be 0.970, indicating an annual survival rate of 0.694 and an overall probability of 0.334 of an individual surviving to age 3, when it could potentially become a breeder. Juvenile caracaras experienced periods of decreased survivorship beginning at two months after fledging, which coincides with the fledglings' independence, and about one year after fledging, when juveniles typically leave their natal breeding area. Along with protecting suitable nesting habitat to enhance survival and breeding of adults, conservation and management strategies for Florida's caracaras should focus on identifying and protecting areas where groups of individuals in the juvenile age class congregate. Such protection would enhance survival of these individuals, thus ensuring their continued recruitment into the breeding population.
Anderson, M.D., Maritz, A.W.A. & Oosthuysen, E. 1999. Raptors drowning in farm reserviors in South Africa. Ostrich 70 (2): 139–144In the arid areas of southern Africa, the drowning of raptors in small reservoirs on farms is a significant cause of mortality. Records of 322 raptors of 29 species which drowned during 163 separate incidents have been collated. Whitebacked Gyps africanus and Cape Vultures Gyps coprotheres, and Martial Polemaetus bellicosus and Black Eagles Aquila verreauxii, were the species most frequently recovered from reservoirs. There are few records of small raptors (
Ecorregiones de la Argentina
- R Burkart
- N O Bárbaro
- R O Sánchez
Burkart, R., N. O. Bárbaro, R. O. Sánchez, and D. A. Gómez
(1999). Ecorregiones de la Argentina. Administración de
Parques Nacionales, Buenos Aires, Argentina.
Abundancia y riqueza de aves de presa en el límite sur de las Yungas
- C A Destefano
Destefano, C. A. (2018). Abundancia y riqueza de aves de
presa en el límite sur de las Yungas. B.S. thesis, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina.
Dirección Provincial de Energía de Corrientes (2017).
Para reforzar la provisión de luz reemplazan los postes
de madera por otros de hormigón. https://www.dpec
.com.ar/959.
San Ignacio-Garita" por los de hormigón armado
- T V Doce
Doce TV (2022). Reemplazaron postes de madera en la línea
de "San Ignacio-Garita" por los de hormigón armado.
https://canal12misiones.com/noticias-de-misiones/
politica-politica/reemplazaron-los-postes-de-madera-en-lalinea-de-doble-terna-33-kv-san-ignacio-garita/.
Mortalidad de fauna silvestre en reservorios de agua en ambientes áridos y semiáridos del centro de Argentina: Cuantificación y evaluación de medidas de mitigación
- M E Giusti
Giusti, M. E. (2016). Mortalidad de fauna silvestre en
reservorios de agua en ambientes áridos y semiáridos
del centro de Argentina: Cuantificación y evaluación
de medidas de mitigación. B.S. thesis. Facultad de
Ciencias Exactas y Naturales, Universidad Nacional de
La Pampa, La Pampa, Argentina.
Goldstein, M. I. (2000). Nest-site characteristics of Crested
Caracaras in La Pampa, Argentina. Journal of Raptor
Research 34:330-333.
Bird interference on high tension electric transmission lines
- T Hallinan
Hallinan, T. (1922) Bird interference on high tension
electric transmission lines. The Auk 39:573. doi: 10.
2307/4073596.
Información Regional (2023). Un carancho se electrocutó
y dejó a Oliveros más de dos horas sin luz. https://www
.informacionregional.com.ar/oliveros/un-carancho-seelectrocuto-y-dejo-a-oliveros-mas-de-dos-horas-sin-luz-36150.html.
Installation of devices in water tanks to prevent drowning of wild animals
- A Lafón
Lafón, A. (2006). Installation of devices in water tanks to
prevent drowning of wild animals. In Grasslands Ecosystems, Endangered Species, and Sustainable Ranching
in the Mexico-US Borderlands: Conference Proceedings (X. Basurto, and D. Hadley, Editors). US
Department of Agriculture, Forest Service, Rocky
Mountain Research Station, Fort Collins, CO, USA. pp.
106-107.
Se firmó el contrato para iniciar la nueva línea de media tensión entre Padre Buodo y Perú
- Secretaría De Energía Y Minería
Secretaría de Energía y Minería (2022). Se firmó el contrato para iniciar la nueva línea de media tensión entre
Padre Buodo y Perú. https://seym.lapampa.gob.ar/
noticias/se-firmo-el-contrato-para-iniciar-la-nuevalinea-de-media-tension-entre-padre-buodo-y-peru.
Raptor ringing in Namibia
- C J Brown
Reemplazaron postes de madera en la línea de “San Ignacio-Garita” por los de hormigón armado
- Tv Doce
Imperiled: The Encyclopedia of Conservation
- J H Sarasola
- D Gallego
- B Martínez-Miranzo
El agua como limitante de la ganadería bovina en la Pampa. 6° Congreso Pampeano del Agua
- P M Vázquez
- C Arroyo