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At least 37 records · Page 2Linked to original sources
USGS1994

Organochlorine pesticides, chlorinated dioxins and furans, and PCBs in peregrine falcon Falco peregrinus eggs from the Kola peninsula, Russia

Nesting of a bog-associated population of mlgfatory Peregrine Falcons, Falco peregrinus, along the Ponoy River depression, Kola Peninsula, Russia, has been studied since 1977. In 1987 91 production rates averaged 1.94 young per active nest and the number of breeding pairs increased from 4 to 10. In 1991, most eyrie sites were visited during the egg stage and a 'sample' egg was collected for contaminant analysis. Eight Peregrine Falcon eggs contained relatively low concentrations of p,p' -DOE (DOE) (geometric mean 3.5 g/g) and of other organochlorine pesticides. These DOE concentrations are similar to those reported in Peregrine Falcon eggs from an Alaskan population that had also showed a recent population increase. Eggshell thinning (11.4%) was similar to that found in Alaska. Concentrations of polychlorinated biphenyls (PCBs) were higher than DOE concentrations, comparable to the contamination profile shown by Peregrine Falcon populations in Fennoscandia, and were higher than those found in Alaskan birds. Before this study, no Peregrine Falcon eggs from Russia had 'been analyzed for PCB congeners, polychlorinated dibenzo- p-dioxins (PCDDs), or pol ychlorinated dibenzofurans (PCD Fs). Conversions of analytical concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), other PCDDs, PCDFs and PCB congeners based on relative aryl hydrocarbon hydroxylase induction potencies allowed the estimation of total 2,3,7,8- TCDD equivalents (TEQs). The TEQs are in the range that is associated with embryonic mortality in other species. Even though the Peregrine Falcon population now seems to be released from decades of a DOT problem, exposure to other contaminant continues. There is an obvious need to assess further the sources and longer-term trends of the PCBs. We also report residue concentrations from one White-tailed Eagle, Haliaeetus albicilla, egg.

Book chapter↗
USGS2002

Prey of the Peregrine Falcon (Falco peregrinus cassini) in Southern Argentina and Chile

The Peregrine Falcon (Falco peregrinus cassini) in Patagonia attracted wide interest two decades ago when there was a focus on determining the taxonomic position of the Pallid Falcon (also called Kleinschmidt's falcon and Tierra del Fuego falcon; formerly named Falco kreyenborgi). In 1981, however, the pallid falcon was confirmed to be a pale color morph of the peregrine, and since that time, little work has been conducted on this color morph. Continent-wide research has continued and has yielded a fair understanding of the breeding distribution of the Peregrine Falcon in South America. Also, two preliminary food habits studies on the peregrine have been completed in Patagonia. Together those papers provided a list of 23 species observed as prey, and McNutt listed another eight species seen pursued (but not captured) by peregrines. The purpose of this paper is to assemble all that has been published on peregrine food habits for Patagonia and Tierra del Fuego and to add to that list from our 1980 and 1981 expeditions.

Journal of Raptor Research↗
USGS2004

Autumn migration and wintering areas of Peregrine Falcons Falco peregrinus nesting on the Kola Peninsula, northern Russia

Four female Peregrine Falcons Falco peregrinus breeding on the Kola Peninsula, Russia, were fitted with satellite-received transmitters in 1994. Their breeding home ranges averaged 1175 (sd = ±714) km 2 , and overlapped considerably. All left their breeding grounds in September and migrated generally south-west along the Baltic Sea. The mean travel rate for three falcons was 190 km/day. Two Falcons wintered on the coasts of France and in southern Spain, which were, respectively, 2909 and 4262 km from their breeding sites. Data on migration routes suggested that Falcons took a near-direct route to the wintering areas. No prolonged stopovers were apparent. The 90% minimum convex polygon winter range of a bird that migrated to Spain encompassed 213 km 2 ( n = 54). The area of the 50% minimum convex polygon was 21.5 km 2 ( n = 29). Data from this study agree with others from North America that show that Falcons breeding in a single area do not necessarily follow the same migratory path southward and do not necessarily use the same wintering grounds.

Kola Peninsula↗
USGS1999

Long-term prairie falcon population changes in relation to prey abundance, weather, land uses, and habitat conditions

We studied a nesting population of Prairie Falcons ( Falco mexicanus ) in the Snake River Birds of Prey National Conservation Area (NCA) from 1974-1997 to identify factors that influence abundance and reproduction. Our sampling period included two major droughts and associated crashes in Townsend's ground squirrel ( Spermophilus townsendii ) populations. The number of Prairie Falcon pairs found on long-term survey segments declined significantly from 1976-1997. Early declines were most severe at the eastern end of the NCA, where fires and agriculture have changed native shrubsteppe habitat. More recent declines occurred in the portion of canyon near the Orchard Training Area (OTA), where the Idaho Army National Guard conducts artillery firing and tank maneuvers. Overall Prairie Falcon reproductive rates were tied closely to annual indexes of ground squirrel abundance, but precipitation before and during the breeding season was related inversely to some measures of reproduction. Most reproductive parameters showed no significant trends over time, but during the 1990s, nesting success and productivity were lower in the stretch of canyon near the OTA than in adjacent areas. Extensive shrub loss, by itself, did not explain the pattern of declines in abundance and reproduction that we observed. Recent military training activities likely have interacted with fire and livestock grazing to create less than favorable foraging opportunities for Prairie Falcons in a large part of the NCA. To maintain Prairie Falcon populations in the NCA, managers should suppress wildfires, restore native plant communities, and regulate potentially incompatible land uses.

The Condor↗
USGS2025

Prairie Falcon (Falco mexicanus) abundance in a National Conservation Area in Idaho has increased since the 1970s–1990s

The Morley Nelson Snake River Birds of Prey National Conservation Area (NCA), in southwestern Idaho, USA supports a large population of breeding Prairie Falcons ( Falco mexicanus ). Abundance of Prairie Falcons in the NCA was previously monitored in 1976–1978 and 1990–1994. That research indicated maximum counts for each period in 1976 and 1992 and a possible population decline across that time span. We assessed the abundance and nesting success of Prairie Falcons in the NCA in 2002–2003 and 2019–2021, and we compared results to data from before 2000 to assess possible population change. Number of nesting pairs increased over 45 years from peak counts of 206, 193, and 217 in the 1970s, 1990s, and early 2000s, respectively, to 257 in 2021. Increases were not concentrated in one region, but widely distributed across the study area. Rates of nesting success in 2002–2003 and 2019–2021 averaged 57 ± 11.8% (SD) at 49.8 ± 3.3 nests observed each year and did not differ from pre-2000 rates. Finally, our analysis showed that in all 10 years in which a full census was conducted, a sampling approach to surveys would have been effective at estimating the number of falcons nesting within the NCA. Prairie Falcons are of conservation concern because of possible population declines in parts of their range. These results illustrate an area with apparently increasing numbers of this important species and highlight the importance of long-term surveys for tracking population fluctuations and the value of a national conservation area for providing raptor breeding habitat.

Idaho↗
USGS2016

Unusual clockwise loop migration lengthens travel distances and increases potential risks for a central Asian, long distance, trans-equatorial migrant, the Red-footed Falcon Falco vespertinus

Capsule: Red-footed Falcons Falco vespertinus migrating from northern Kazakhstan proceed west before heading south to Africa; their northbound travel follows a different route with passage close to shooting hotspots in the Mediterranean. Aim: To use tracking and ringing data to document for the first time the migration of globally threatened Red-footed Falcons from northern Kazakhstan. Methods: Light-level geolocators were deployed on breeding adults in Kazakhstan and recovered one year later. Ringing and observational data from more than 100 years of Russian-language and other literature were summarized and mapped alongside the geolocator data. Results: Geolocator, ringing and observational data together demonstrate that Red-footed Falcons from northern Kazakhstan have a clockwise loop migration that begins with a long and unusual westward trek around eastern Europe’s large inland seas before continuing to extreme southern Africa. Return migration is farther west and requires crossing two major migratory barriers: the Sahara and the Mediterranean. Conclusion: The loop migration we describe requires an extensive longitudinal movement, exposes central Asian Red-footed Falcons to multiple desert, mountain and marine crossings, and, at outbound and return Mediterranean bottlenecks, crosses sites where raptor shooting is common.

Bird Study↗
USGS2017

Demographic consequences of nest box use for Red-footed Falcons Falco vespertinus in Central Asia

Nest box programs are frequently implemented for the conservation of cavity-nesting birds, but their effectiveness is rarely evaluated in comparison to birds not using nest boxes. In the European Palearctic, Red-footed Falcon Falco vespertinus populations are both of high conservation concern and are strongly associated with nest box programs in heavily managed landscapes. We used a 21-year monitoring dataset collected on 753 nesting attempts by Red-footed Falcons in unmanaged natural or semi-natural habitats to provide basic information on this poorly known species; to evaluate long-term demographic trends; and to evaluate response of demographic parameters of Red-footed Falcons to environmental factors including use of nest boxes. We observed significant differences among years in laying date, offspring loss, and numbers of fledglings produced, but not in egg production. Of these four parameters, offspring loss and, to a lesser extent, number of fledglings exhibited directional trends over time. Variation in laying date and in numbers of eggs were not well explained by any one model, but instead by combinations of models, each with informative terms for nest type. Nevertheless, laying in nest boxes occurred 2.10 ± 0.70 days earlier than in natural nests. In contrast, variation in both offspring loss and numbers of fledglings produced were fairly well explained by a single model including terms for nest type, nest location, and an interaction between the two parameters (65% and 81% model weights respectively), with highest offspring loss in nest boxes on forest edges. Because, for other species, earlier laying dates are associated with more fit individuals, this interaction highlighted a possible ecological trap, whereby birds using nest boxes on forest edges lay eggs earlier but suffer greater offspring loss and produce lower numbers of fledglings than do those in other nesting settings. If nest boxes increase offspring loss for Red-footed Falcons in heavily managed landscapes where populations are at greater risk, or for the many other species of rare or endangered birds supported by nest box programs, these processes could have important demographic and conservation consequences.

Ibis↗
USGS2017

Intraspecific evolutionary relationships among peregrine falcons in western North American high latitudes

Subspecies relationships within the peregrine falcon ( Falco peregrinus ) have been long debated because of the polytypic nature of melanin-based plumage characteristics used in subspecies designations and potential differentiation of local subpopulations due to philopatry. In North America, understanding the evolutionary relationships among subspecies may have been further complicated by the introduction of captive bred peregrines originating from non-native stock, as part of recovery efforts associated with mid 20 th century population declines resulting from organochloride pollution. Alaska hosts all three nominal subspecies of North American peregrine falcons– F . p . tundrius , anatum , and pealei –for which distributions in Alaska are broadly associated with nesting locales within Arctic, boreal, and south coastal maritime habitats, respectively. Unlike elsewhere, populations of peregrine falcon in Alaska were not augmented by captive-bred birds during the late 20 th century recovery efforts. Population genetic differentiation analyses of peregrine populations in Alaska, based on sequence data from the mitochondrial DNA control region and fragment data from microsatellite loci, failed to uncover genetic distinction between populations of peregrines occupying Arctic and boreal Alaskan locales. However, the maritime subspecies, pealei , was genetically differentiated from Arctic and boreal populations, and substructured into eastern and western populations. Levels of interpopulational gene flow between anatum and tundrius were generally higher than between pealei and either anatum or tundrius . Estimates based on both marker types revealed gene flow between augmented Canadian populations and unaugmented Alaskan populations. While we make no attempt at formal taxonomic revision, our data suggest that peregrine falcons occupying habitats in Alaska and the North Pacific coast of North America belong to two distinct regional groupings–a coastal grouping ( pealei ) and a boreal/Arctic grouping (currently anatum and tundrius )–each comprised of discrete populations that are variously intra-regionally connected.

Alaska↗
USGS2005

Spacing and physical habitat selection patterns by peregrine falcons in central West Greenland

We examined nest-site spacing and selection of nesting cliffs by Peregrine Falcons ( Falco peregrinus ) in central West Greenland. Our sample included 67 nesting cliffs that were occupied at least once between 1972 and 1999 and 38 cliffs with no known history of Peregrine Falcon occupancy. We measured 29 eyrie, cliff, and topographical features at each occupied nesting cliff and unused cliff in 1998a??1999 and used them to model the probability of peregrines occupying a cliff for a breeding attempt. Nearest-neighbor distance was significantly greater than both nearest-cliff distance and nearest-occupied distance (the distance between an occupied cliff and one occupied at least once, 1972a??1999). Thus, spacing among occupied cliffs was probably the most important factor limiting nesting-cliff availability, and, ultimately, peregrine nesting densities. Although some unused cliffs were unavailable in a given year because of peregrine spacing behavior, physical characteristics apparently made some cliffs unsuitable, regardless of availability. We confirmed the importance of several features common to descriptions of peregrine nesting habitat and found that peregrines occupied tall nesting cliffs with open views. They chose nesting cliffs with eyrie ledges that provided a moderate degree of overhang protection and that were inaccessible to ground predators. Overall, we concluded that certain features of a cliff were important in determining its suitability as a nest site, but within a given breeding season there also must be sufficient spacing between neighboring falcon pairs. Our habitat model and information on spacing requirements may be applicable to other areas of Greenland and the Arctic, and can be used to test the generalities about features of Peregrine Falcon nesting cliffs throughout the species' widespread distribution.

Kangerlussuaq↗
USGS2007

Further assessment of environmental contaminants in avian prey of the peregrine falcon in big bend National Park, Texas

A small resident population of peregrine falcons (Falco peregrinus anatum) in the Big Bend region of Texas has suffered reproductive failures since 1990. To continue our assessment of the effects of environmental contaminants on the peregrine falcon, we collected representative avian prey species during 2001 at Mariscal Canyon, Big Bend National Park. The avian carcasses were analyzed for inorganic and organochlorine contaminants. Concentrations of Se and Hg were present at high levels (up to 11 and 2.2 ??g/g dry weight, respectively) in some avian prey and could be implicated in reproductive failures of the peregrine falcon in Big Bend National Park. All other inorganic elements were below concentrations known to affect reproduction or to be associated with other deleterious effects in birds. Of all the organochlorines analyzed, only DDE and total PCBs were present above detection limits in all species, although at low concentrations. Our study provides further support to the hypothesis that contaminants in potential avian prey of the peregrine falcon in the Big Bend region are implicated in the productivity failures observed in this species since 1990.

Southwestern Naturalist↗
USGS1998

Routes and travel rates of migrating Peregrine Falcons Falco peregrinus and Swainson's Hawks Buteo swainsoni in the Western Hemisphere

We describe and compare the migration routes, length of migration, and duration of migration of Peregrine Falcons Falco peregrinus tundrius and Swainson's Hawks Buteo swainsoni in the Western Hemisphere. We radio tracked migrants using the Argos satellite system. Our initial samples were 34 Swainson's Hawks from representative areas of their breeding range, and 61 Peregrine Falcons captured at nest sites across the North American boreal forest and low Arctic or on the migration routes along the mid-Atlantic and Gulf of Mexico coasts. The average distance of migration for Peregrines was 8,624 km southward, and 8,247 km northward. Peregrines travelled at an average rate of 172 km/d southward and 198 km/d going north. Peregrine Falcons used at least three broad, general routes south from the breeding areas, and individuals stopped migrating as far north as the U.S.A. mid-Atlantic coast and as far south as central Argentina. The radiomarked Peregrine Falcons used coastal routes, mid-continental routes, and water-crossing routes: the Davis Strait and Caribbean Sea. During northward migration, Peregrines migrating through at Padre Island, Texas diverged for destinations from central Alaska across the continent to central West Greenland. Swainson's Hawks migrated an average of about 13,504 km southward and 11,952 km northward, and travelled 188 km/d southward and 150 km/d northward. Swainson's Hawks converged in eastern Mexico on the Gulf of Mexico coast. Southward, these hawks followed a narrow, well-defined path through Central America, across the Andes Mountains in Columbia, and east of the Andes to central Argentina where they all spent the austral summer. Swainson's Hawks northward migration largely retraced their southward route.

Journal of Avian Biology↗
USGS1996

Influence of radio transmitters on prairie falcons (Falco mexicanus)

We examined the effects of backpack radio transmitters on Prairie Falcon (Falco mexicanus) reproduction (percentage of occupied territories producing young and number of nestlings produced) over four years. In addition, we observed falcon aeries during brood-rearing to determine attendance at the nest and in the territory, prey delivery rates, and prey composition. We found no effect of radio tagging on Prairie Falcon productivity (nesting success and brood size) among years, although productivity varied significantly among years. The sex of the falcon tagged did not affect productivity. Radio-tagged members of pairs did not differ significantly from un-tagged members of pairs in territory attendance, nest attendance, prey delivery rates, or caching rates. Nestlings raised by radio-tagged parents attained masses similar to those reared by control parents. During low prey years, radio-tagged males brought a greater proportion of small birds and reptiles, and fewer mammals to the nest area than control males.

Journal of Field Ornithology↗
USGS1982

The peregrine falcon in Arizona: Habitat utilization and management recommendations

The peregrine falcon once bred in significant numbers in Arizona. Good documentation is available for specific breeding sites and an additional 20 general locations. This report, based on the published literature, an extensive personal contact survey, an aerial habitat inventory (over 124 hours air time), and ground visits to over 300 locations, provides information on habitat preferences and management practices which can contribute to the bird's survival. In seeking to identify the habitat preferences of the falcon, many site description factors were examined. Those traits which appeared common to most recent Arizona sites (and therefore most useful in evaluating habitat) were: elevation less than 9,000 feet, cliffs tall or very tall, cliffs extensive, topographic relief high, and surface water readily available. All recent sites are in extensive canyon systems or in extensive mountain ranges. Using a habitat evaluation key derived from the traits common to known breeding sites, all cliff regions in Arizona and the Navajo Indian Reservation were flown and evaluated for suitability. Nineteen falcon eyries located in subsequent ground visits were all in areas previously ranked acceptable or better. Many management alternatives are discussed: management of information on breeding sites, habitat preservation, controlling disruptive human activities, and enhancing productivity through the creation of suitable breeding ledges, providing pesticide free prey, or direct reintroductions. Given their privacy (and an increasingly pesticide free environment) the peregrine falcon will likely exist indefinitely in suitable areas across Arizona.

Institute for Raptor Studies Research Reports↗
USGS1995

The Altay falcon: Origin, morphology and distribution

The systematic position of the Altay falcon (Falco altaicus lorenzi) is perhaps the most enigmatic question lingering in falcon taxonomy. First reported to science in 1811, it has been treated as a race of the gyrfalcon (F. rusticolus), as a race of the saker (F. cherrug), as two separate species (F. lorenzi and F. altaicus), and as one to three color morphs of either the saker or the gyrfalcon. Ironically, two or even more of these explanations may be correct. Of 53 specimens examined, at least two are misidentified gyrfalcons, a score I dismiss as typical sakers, but a sizeable group (N = 34) is retained as representing what I consider to be the true Altay falcon type. Three adult color morphs exist: red, brown and grey. The red-backed morph closely resembles some eastern sakers. The chocolate morph resembles the black gyrfalcon from Labrador. The grey morph resembles the grey morph of the gyrfalcon. Ecological, geographical and morphological information contribute to the conclusion that this core group represents a gyrfalcon-saker hybrid that is very likely being swamped into obscurity through back crosses with the saker. The breeding range reported herein (Altay-Sayan Mountains) is greatly contracted from that previously reported. The true identify of the Altay falcon will be resolved by molecular genetics.

Book chapter↗
USGS2017

Are nest boxes ecological traps for red-footed falcons Falco vespertinius at Naurzum

Nest box programs are frequently implemented for conservation of cavity-nesting birds, but their effectiveness is rarely evaluated in comparison to birds not using nest boxes. In the European Palearctic, Red-Footed Falcon ( Falco vespertinus ) populations are both of high conservation concern and are strongly associated with nest box programs in heavily managed landscapes. We used a 21-year monitoring dataset developed from monitoring 753 nesting attempts by Red-footed Falcons at the Naurzum Zapovednick to evaluate response of demographic parameters of Redfooted Falcons to environmental factors including use of nest boxes. Variations in lay date and in numbers of eggs were not well explained by any one model, but instead by combinations of models with terms for nest type, land cover type and degree of coloniality. In contrast, variation in both offspring loss and numbers of fledglings produced were fairly well explained by a single model including terms for nest type, land cover type, and an interaction between the two parameters (65% and 81% model weights respectively). Because, for other species, early lay dates are associated with individual fitness, this interaction highlighted a potential ecological trap where falcons using nest boxes on forest edges at Naurzum lay eggs earlier but suffer greater offspring loss and produce lower numbers of fledglings than do those in other nesting settings.

Kostanay Oblast↗
USGS2000

Species variation in osmotic, cryoprotectant, and cooling rate tolerance in poultry, eagle, and Peregrine Falcon spermatozoa

Potential factors influencing spermatozoa survival to cryopreservation and thawing were analyzed across a range of the following avian species: domestic chicken ( Gallus domesticus ), domestic turkey ( Meleagris gallopavo ), golden eagle ( Aquila chrysaetos ), Bonelli’s eagle ( Hieraaetus fasciatus ), imperial eagle ( Aquila adalberti ), and peregrine falcon ( Falco peregrinus ). Studies focused on spermatozoa tolerance to the following: 1) osmotic stress, 2) different extracellular concentrations of the cryoprotectant dimethylacetamide (DMA), 3) equilibration times of 1 versus 4 h, 4) equilibration temperature of 4 versus 21°C, and 5) rapid versus slow cooling before cryopreservation and standard thawing. Sperm viability was assessed with the live/dead stain (SYBR-14/propidium iodine). Sperm viability at osmolalities ≥800 mOsm was higher ( P < 0.05) in raptor than poultry semen. Return to isotonicity after exposure to hypertonicity (3000 mOsm) decreased ( P < 0.05) number of viable spermatozoa in chicken, turkey, and golden and Bonelli’s eagle spermatozoa but not in imperial eagle or peregrine falcon spermatozoa. Differences were found in spermatozoa resistance to hypotonic conditions, with eagle species demonstrating the most tolerance. Semen, equilibrated for 1 h (4°C) in diluent containing DMA (≥2.06 M), experienced decreased ( P < 0.05) spermatozoa survival in all species, except the golden eagle and peregrine falcon. Number of surviving spermatozoa diminished progressively with increasing DMA concentrations in all species. Increased equilibration temperature (from 4 to 21°C) markedly reduced ( P < 0.05) spermatozoa survival in all species except the Bonelli’s eagle and turkey. Rapid cooling was detrimental ( P < 0.05) to spermatozoa from all species except the imperial eagle and the chicken. These results demonstrate that avian spermatozoa differ remarkably in response to osmotic changes, DMA concentrations, equilibration time, temperature, and survival after fast or slow freezing. These differences emphasize the need for species-specific studies in the development and enhancement of assisted breeding for poultry and endangered species.

Biology of Reproduction↗
USGS1999

Siblicide, splayed-toes-flight display, and grappling in the Saker Falcon

We observed two incidents of novel social behavior in the saker falcon (Falco cherrug) in Mongolia. First, we provide an account of a two-week-old saker falcon chick killing its nest mate, the first direct observation of siblicide in the genus Falco. We also report aerial combat between three adult saker falcons including observations of talon grappling, whirling, and Splayed-toes-flight, a previously undescribed social display.

Journal of Raptor Research↗
USGS2021

Red-footed Falcon Falco vespertinus

Red-footed falcons (Falco vespertinus) are a small, long-distance and obligate migrant falcon that breeds at the forest-steppe interface in Eurasia and winters in Southern Africa. Research carried out with geolocators and satellite transmitters show that during the southbound migration Central Asian birds migrate through the Caucasus and the Middle East, while those from Eastern Europe cross the Eastern Mediterranean. Once in Africa, they cross the Sahara, the Sahel, where they perform short stopovers, and the Congo rainforest or the Rift valley, heading towards the wintering grounds. Northbound migration involves stopovers in West Africa and long crossings over the Mediterranean Sea. Both visual observations and tracking studies show that at least some populations of the species perform a clockwise loop migration that involves extensive longitudinal movements and. for some sub-populations, crossing the Central Mediterranean only during spring. Pre-breeding migration has a longer duration than post-breeding migration, probably because stopovers are longer and wind assistance lower. Red-footed falcons also face substantial anthropogenic threats along migration, particularly the risk of shooting at migratory bottlenecks.

Book chapter↗