Falcon Population Research Articles

Where have all the falcons gone? Saker falcon (falco cherrug) exports in a global economy

Within conservation biology growing evidence of the decline of the Saker falcon (falco cherrug) population has directed attention to the role of the global falcon trade. Here, we examine factors that may explain the global Saker trade using ecological modernization, treadmill of production and unequal ecological exchange as theoretical frameworks. We estimate trends in Saker exports using the most comprehensive measure available – Convention on International Trade in Endangered Species of Wild Fauna and Flora Trade Database. Our analysis employs fixed effects regression techniques to control for unobserved heterogeneity between nations to isolate the most important drivers of Saker exports. We find that the rise in Saker exports are partly correlated with a nation's increasing income and growing dependence on trade. Such a situation infers that the global Saker falcon population will continue to diminish if conservation policy does not change and current economic conditions continue.

Результаты апробирования методики восстановления популяции балобана путём подсадки в естественные гнёзда птенцов, выращенных в питомнике (с результатами GPS/GSM-трекинга слётков)

Летом 2018 г. в Республике Тыва был реализован второй выпуск в природу птенцов алтайской морфы балобана ( Falco cherrug ) путём подсаживания 19 выращенных в питомниках птенцов в естественные гнёзда балобанов других морф. Птенцы из двух питомников были рассажены по 10 гнёздам с 31 нативным птенцом. Один птенец из питомника был изъят из гнезда до вылета по причине травмы. Отход среди оставшихся 49 птенцов до вылета из гнёзд отсутствовал, подсаженные в гнёзда птенцы из питомников и нативные птенцы балобана успешно встали на крыло. Отход после вылета и до распада выводков составил 5 птенцов (10,2%): 2 птенца из питомника были добыты крупными пернатыми хищниками и 3 нативных птенца погибли на гнездовых участках от переохлаждения и голода в периоды ненастья в июле. Для двух птенцов из питомника и двух нативных птенцов прослежена миграция с помощью GPS/GSM-трекеров.

Prevalence of Caryospora Species (Apicomplexa: Eimeriidae) in Falcons in the United Arab Emirates.

A total of 3975 fecal samples, originated from the same number of individual birds, from 7 dedicated falcon hospitals, were examined to determine the prevalence of Caryospora species in the falcon population used in the sport of falconry in the United Arab Emirates (UAE). From that total, 297 (7.5%) were positive for the presence of Caryospora species. The falcons were all captive bred within the UAE and abroad, mainly from Germany, Spain, the United States, and Canada. Positive samples for the presence of Caryospora species were sporulated, and the taxonomy was established based on morphologic characteristics. The results showed the prevalence of the following Caryospora species: C kutzeri 41.4%, C neofalconis 25.6%, C megafalconis 18.2%, C falconis 10.4%, C cherrughi 3.7%, and C boeri 0.7%. The prevalence of Caryospora species among the various falcon species in this study was: gyr × peregrine hybrid falcons ( Falco rusticolus × Falco peregrinus), 27.3%; gyr falcons ( Falco rusticolus), 25.6%; peregrine falcons ( Falco peregrinus), 20.5%; saker falcons ( Falco cherrug), 16.5%; gyr × saker hybrid falcons ( Falco rusticolus × Falco cherrug), 8.1%; Eurasian kestrels ( Falco tinnunculus), 1%; red-napped shaheen ( Falco pelegrinoides babylonicus), 0.7%; and American kestrels ( Falco sparverius), 0.3%.

Spatio-temporal trends in the predation of large gulls by peregrine falcons (Falco peregrinus) in an insular breeding population

Abstract Individual diet specialization occurs in many populations of generalist predators, with specific individuals developing specialist strategies in their feeding behaviour. Intraspecific resource partitioning is hypothesised to be common amongst species in higher trophic levels where competition for resources is intense, and a key driver in breeding success and community structure. Though well-studied in other predators, there is sparse data on ecological specialization in raptors, which are important drivers of community and trophic structure. In this study, the breeding season diet of an insular population of peregrine falcons (Falco peregrinus) was determined from indirect analysis of prey remains collected over three years. An unexpected result was the high proportion of large gulls (Laridae), of the genus Larus, in the diet of two breeding pairs of peregrines. Large gulls made up 18.44% by frequency of total prey recorded and 30.81% by biomass. Herring gulls (Larus argentatus) were the most common large gull prey, with immatures most frequent (67.95%) compared to adults (19.23%). Overall, most gulls predated were immatures (80.77%). Frequency of predation varied between breeding pairs and months, but was consistent over the three years. Most gulls were taken in April (37.17%), followed by May (19.23%), with a smaller peak of immature herring gulls taken in August and September. The pattern of regular predation by peregrines on large gulls is a new observation with important implications for understanding individual diet specialization in raptors, and its effect on bird populations and community structure.

Monitoring of colonies and provisioning of rooks with nest material as a potential tool for stabilizing colonies and increasing nesting opportunities in the countryside. Project report

Abstract The rook is a species inhabiting open agricultural landscape whose non-active nests are also used by other bird species for nesting. It is the decline in rook colonies that has been posited as one of the reasons for decrease in the red-footed falcon (Falco vespertinus) population in Slovakia since the 1970s. During the period from 2012 till 2016, four monitorings of rook colonies were carried out in south-western Slovakia (Diakovce, Nitrianska Osada, Sokolce and Tvrdošovce). In the colony at Tvrdošovce, supporting activity involving provisioning of rooks with nest material was under way from 2014 until 2016. While the colonies at Diakovce and Nitrianska Osada have been showing a slight decrease in the number of nesting rooks, despite larger interannual differences the colony at Sokolce has been showing an upward trend. The size of the colony at Tvrdošovce has been stable since the beginning of the supporting activity. This activity had a statistically significant positive effect on the width of rook nests. In 74 cases in the studied rook colonies we have recorded nesting by three other bird species – Eurasian kestrel (Falco tinnunculus) 43.8%, western jackdaw (Corvus monedula) 39.7% and long-eared owl (Asio otus) 16.4%. In 2015 two female redfooted falcons were observed in the colony at Tvrdošovce.

Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

Abstract The red-footed falcon and Eurasian falcon represent two syntopical falcon species. While the Eurasian falcon is considered a common and numerous species in Slovakia, the red-footed falcon population has undergone a considerable decline during the past few decades. Nowadays it nests in a single locality in Slovakia, the Sysľovské polia Special Protection Area, which forms the northern and fragmented border of the species distribution area in Europe. By analysing prey remains from 9 nests (from 1998, 2001, 2013, 2014 and 2016), we identified 433 prey items belonging to 35 taxa and 9 orders. Every year, invertebrates made up the major part of the diet spectrum, in which Calosoma auropunctatum, Tettigonia viridissima, Zabrus tenebrioides, Anisoplia aegetum and Rhizotrogus sp. were the most frequent species of prey. Of the vertebrates, Microtus arvalis was the most hunted prey species. By supplementary analysis of 21 photos, we extended our knowledge on the diet by other 6 taxa. The peak of the M. arvalis population growth in 2014 did not manifest itself in the red-footed falcon diet composition. In 1998, 2014 and 2016 we also studied the diet of a syntopical species, the Eurasian kestrel. By analysing prey remains in 22 nests, we identified 1,151 prey items belonging to 37 taxa and 7 orders. In 1998 and 2014 vertebrates predominated, especially the common vole, however in 2016 invertebrates prevailed. This fact could be a reaction to the M. arvalis population peak in 2014 and its decline in 2016. These results suggest that this variability in the foraging behaviour of the Eurasian kestrel, an opportunistic predator, during the hunting of invertebrates increases the diet similarity and overlapping of the food niche of both studied falcon species.

Long-term continental changes in wing length, but not bill length, of a long-distance migratory shorebird.

We compiled a >50‐year record of morphometrics for semipalmated sandpipers (Calidris pusilla), a shorebird species with a Nearctic breeding distribution and intercontinental migration to South America. Our data included >57,000 individuals captured 1972–2015 at five breeding locations and three major stopover sites, plus 139 museum specimens collected in earlier decades. Wing length increased by ca. 1.5 mm (>1%) prior to 1980, followed by a decrease of 3.85 mm (nearly 4%) over the subsequent 35 years. This can account for previously reported changes in metrics at a migratory stopover site from 1985 to 2006. Wing length decreased at a rate of 1,098 darwins, or 0.176 haldanes, within the ranges of other field studies of phenotypic change. Bill length, in contrast, showed no consistent change over the full period of our study. Decreased body size as a universal response of animal populations to climate warming, and several other potential mechanisms, are unable to account for the increasing and decreasing wing length pattern observed. We propose that the post‐WWII near‐extirpation of falcon populations and their post‐1973 recovery driven by the widespread use and subsequent limitation on DDT in North America selected initially for greater flight efficiency and latterly for greater agility. This predation danger hypothesis accounts for many features of the morphometric data and deserves further investigation in this and other species.

Recovery and Range Expansion in a North Central Utah Peregrine Falcon Population

Abstract. Peregrine Falcon numbers in much of the Intermountain West rebounded after a decline during the 1950s, 1960s, and early 1970s. However, recent literature regarding the species suggested that little, if any, growth was occurring in populous north central Utah, which once supported a robust Peregrine Falcon population. A concerted reintroduction effort during the 1980s resulted in establishment of nesting pairs of Peregrine Falcons on artificial towers where they were originally released as nestlings, but traditional nesting cliffs generally remained vacant. More recently, numerous Peregrine Falcon pairs have been observed nesting on cliffs both within and adjacent to their historical range in the region. I combined results from recent literature with numbers gleaned during this study to find that 45 Peregrine Falcon nesting territories are documented for the recovery era in north central Utah.

Turnover and post‐bottleneck genetic structure in a recovering population of Peregrine Falcons Falco peregrinus

Dispersal is a process that increases genetic diversity and genetic connectivity of populations. We studied the turnover rate of breeding adults and genetic population structure to estimate dispersal in Peregrine Falcons in Finland. We used relatedness estimates among Finnish Peregrine Falcons over a 5‐year period, genotyping over 500 nestlings with 10 microsatellite loci to reveal the rate of turnover. Our results reveal a high turnover rate (21.7%) that does not seem to be correlated with the breeding success of the previous year. The extent of population genetic structure and diversity, and possible signs of the population crash during the 1970s, was assessed with a reduced dataset, excluding relatives. We found genetic diversity to be similar to previously studied falcon populations (expected heterozygosity of 0.581) and no population genetic structuring among our sampled populations. We did not find a genetic imprint of the past population bottleneck that the Finnish Peregrine population experienced. We conclude that high dispersal rates are likely to have contributed to maintaining genetic diversity across the landscape, by mixing individuals within the species’ distribution in Finland and thus preventing genetic structuring and negative effects associated with the population decline in the 1970s.

Peregrine Falcon (Falco peregrinus) may affect local demographic trends of wetland bird prey species

The demographic value of existing habitat can be affected by changes in predator populations. In Finland, wader populations increased when the Peregrine Falcon (Falco peregrinus) declined, due to poisoning by agricultural chemicals during the 1960–1970. Following regulation ofDDTusage, nesting Peregrinenumbers have increasedmore than tenfold, while wader populations concurrently declined. The “protection” hypothesis states that although top predators may negatively affect populations of primary prey species, they may benefit other species populations by suppressing activities of mesopredators, such as egg and chick predation.We studied diet preferences of Peregrine Falcons in south-west Finnish Lapland during a period of falcon population growth, based on indices of species consumption versus availability. Preferred and optimal sized prey species, excluding ducks, were equally abundant on bogs with and without Peregrines, and neither did the abundance of non-preferred or non-optimal sized birds differ between bogs with and without Peregrines. Thus, the protection hypothesis was supported for ducks. We found that preferred prey species significantly declined in numbers over time, while populations of non-preferred and non-optimal sized prey species declined less or remained stable, as expected if Peregrines would have direct negative effects on prey species. However, local effects were apparent when comparing local versus national trends of suitable and less suitable sized prey for the Peregrines.While the raptors’ role in the population declines of wetland speciesmust have increased after their recovery in the 1970s, this effect might be difficult to separate from other concurrent effects of habitat loss.

겨울철 한강 장항습지에 서식하는 매 멸종확률 예측에 대한 연구

매(Falco peregrinus)는 천연기념물 323호이며 멸종위기종으로 등재되어 있다. 본 연구는 한강의 장항습지에 서식하는 매의 멸종확률을 개체군변이분석을 통하여 시도하고자 한다. 장항습지는 개체군이 1999-2005년 동안 모니터링되었으며 평균 10.8 개체가 서식하는 것으로 조사되었으며, 개체군을 이용하여 향후 5년간(2015-2020) 변이분석을 실시하였다. 초기개체군을 이용하여 기간 동안 20%의 멸종확률이 예측되었으며, 이 확률은 지역의 수질오염과 서식지 손실을 고려하면 적은 것으로 나타났다. PVA는 개체군이 적고 다른 정보가 부족한 종에 대해 실시한다. 또한 매의 개체군은 댐의 보 및 콘크리트 제방 등을 고려하면 멸종의 확률이 증가될 것으로 사료된다. 장기적인 생활사 등을 고려한 연구가 필요하다. Peregrine falcon (Falco peregrinus) are listed as endangered species and Natural monument #323 in Korea, and this study examined the possibility of extinct of peregrine falcon in Jang Hang wetland near Han river using with the application of Population Viability Analysis (PVA) technique. In Jang Hang wetland areas population was monitored during 1999-2005 averaging 10.8 individuals and PVA analysis was done for the 5 years (2015-2020) using the average population size. Using the initial population was estimated 20% of extinct rate during the time. This estimation was quite low considering water pollution and loss of habitat. Also PVA only used population size lacking in other life history information. Nonetheless falcon population can be in risk of extinction if the current construction of crossovers in the river, cement bank are maintained. Long term information regarding life history needs essential.

Long-term Reproduction (1984–2013), Nestling Diet, and Eggshell Thickness of Peregrine Falcons (Falco peregrinus) in Yellowstone National Park

Abstract Peregrine Falcons (Falco peregrinus) were extirpated from Yellowstone National Park (YNP) by 1970 as a result of widespread use of DDT (dichloro-diphenyl-trichloroethane) throughout North America from the late 1940s to the early 1970s. DDT, and its primary metabolite DDE (dichloro-diphenyl-dichloroethylene), caused eggshell thinning and impaired reproduction in Peregrine Falcons and other raptors. Restoration of Yellowstone’s Peregrine Falcon population began with nationwide restrictions placed on the use of DDT in 1972, coupled with the release of 36 captive-raised juveniles in YNP and the dispersal of 644 captive-raised juvenile Peregrine Falcons released within 260 km of YNP. We monitored Peregrine Falcon reestablishment and reproductive success in YNP (nesting success, productivity, and brood size) from 1984–2013. Productivity was defined as the number of young reaching ≥28 d per territorial pair. Brood size referred to the number of young reaching ≥28 d per successful pair. From 2010–2013, w...

Origin, Growth, and Composition of the Recovering Peregrine Falcon Population in Ontario

After an absence of more than two decades, Peregrine Falcons (Falco peregrinus) resumed nesting in Ontario in 1986. Between 1991 and 2006, at least 193 young fledged in southern Ontario and 548 young fledged in northern Ontario. The number of breeding pairs, nesting attempts, successful nests, and young fledged all steadily increased in both regions throughout this period. In southern Ontario, 25% of the breeding adults produced nearly 50% of all fledglings, and 87% of the fledglings came from just eight breeding sites. Direction of natal dispersal was variable, but females consistently moved farther than males, and there was frequent movement both to and from adjacent American states. The population recovery resulted from the release of 592 captive-bred F. p. anatum juveniles in Ontario between 1977 and 2005, plus immigration from other provinces and release efforts in adjacent regions of the United States, where at least five subspecies contributed to the gene pool of captive-bred birds. Encounter rates for both captive-bred and wild-fledged young in Ontario have been low, but wild-raised young have been recruited to the breeding population almost twice as frequently as captive-bred birds. This difference partially explains the genetic composition of the southern Ontario population, where at most 21% of nesting attempts between 1995 and 2006 involved a pair of Canadian-released anatum adults, and 59% of cases involved at least one adult of American origin. Therefore, although the Ontario population has exceeded documented historical levels, it may not be greater than actual historical numbers, and it cannot be strictly considered an anatum population.

History and current status of Red-footed Falcon population size and conservation activities in Voivodina

Abstract The Red-footed Falcon population in Voivodina shows a considerable decrease on a large temporal scale, however due to recent conservation measures, it seems to be stable in the past six years. Here I present the history of population estimates and results of partial surveys that have been carried out since 1909. I also show the details and results of conservation efforts recently implemented in the region. Recovery records of individually colour ringed birds indicate that the population breeding in northern Serbia is an integral part of the Carpathian Basin population and thus conservation management should be coordinated within a framework of international cooperation.

Результаты мониторинга популяции балобана в Алтае-Саянском регионе в 2014 году; Россия

Based on author’s research in 2014 the paper contains information on distribution, numbers and breeding biology of the Saker Falcon ( Falco cherrug ) in the Altai-Sayan region. A total of 112 breeding territories of the Saker Falcon (28.9% of the territories already known in the Altai-Sayan region) located in the Krasnoyarsk Kray, Khakassia, Tyva and Altai Republics were visited in 2014: 94 territories were occupied and 44 territories were successful. Six new territories were discovered in 2014, 7 – recovered within borders of an old empty territory and 11 – were noted as abandoned in 2014. A total of 25 breeding territories of the Saker Falcon located in the Altai Kray were visited in 2014: 4 territories were occupied and 3 territories were successful. Considering the expert estimation a total of 1237–1473 pairs (averaging 1355 pairs) breed in the Altai-Sayan region in 2014, and 618–736 pairs (averaging 677 pairs) are successful. The population trend was noted as negative and was -26% per past 12 years of the census conducted. The positive population trend for the Saker Falcon has been recorded for the last 3 years due to the growth of its population in Tuva – 2% for the region. Estimation a total of 34–45 pairs (averaging 39 pairs) breed in the Altai Kray in 2014, and 17–22 pairs (averaging 19 pairs) are successful. The population trend was noted as negative and was -67% per past 12 years of the census conducted (Saker Falcon population in the pine forests has virtually been extinct).

Trapping of Saker Falcon Falco cherrug and Peregrine Falcon Falco peregrinus in Saudi Arabia: Implications for biodiversity conservation

The numbers of Falco cherrug and Falco peregrinus trapped during their migration over the Kingdom of Saudi Arabia (KSA) were investigated from published reports and through interviews with well-known trappers and dealers over several years (1989–2013). The number of trapped individuals increased for both species over a 23year period, which is probably related to an enhanced trapping effort. Time series analysis suggests that the number of Saker Falcons being trapped is likely to be stable with annual fluctuations in the coming ten-year period, whereas the number of trapped Peregrine Falcons will probably decline with a small fluctuation initially. Using the population viability analysis suggests a high extinction rate for the Saker Falcon population migrating through KSA during the coming 10 and 20years; whereas Peregrine Falcons probably take more than 100years to reach the extinction threshold. However, the increase in the trapping period, especially in the spring, that has been observed during the last five years could increase the number of falcons trapped in the future. As both falcon species are migratory, implementing conservation actions across all range states is important to ensure a favourable conservation status for the Saker and Peregrine Falcons. Both species will benefit through the implementation of the Global Action Plan (GAP), developed by the Saker Falcon Task Force.

The saker falcon (Falco cherrug) population, diet and nest boxes in Slovakia: LIFE-project report 2011–2014

Abstract From October 201 0 until December 201 4 the LIFE09 NAT/HU/000384 project was implemented in four Special Protected Areas in Slovakia. The recent project was complementary to a previous LIFE project implemented between 2006 and 201 0. Both projects supported regular monitoring of the population of saker falcon and new approaches to conservation of the species. The LIFE09 project helped to increase knowledge about the prey composition and the behaviour of the species. The population was strongly affected in 201 3 by extremely bad weather conditions (1 .79 fledglings/breeding attempt). Although the total number of saker falcon pairs in Slovakia is thought to be higher, 31 pairs were breeding in 201 4. By analysis of the diet (2991 individuals), 47 prey species were identified, from which birds were predominant (80%). More than half of the diet consisted of feral pigeons (Columba livia f. domestica) (59%)

Productivity, mortality, and management of urban peregrine falcons in northeastern North America

The peregrine falcon (Falco peregrinus) population in eastern North America has grown significantly since the early 1980s, especially in urban areas, but few studies have assessed the factors that influence productivity. We reviewed all documented nesting attempts from southern Ontario, Quebec, Massachusetts, New Jersey, and Pennsylvania from 1980 through 2006 to evaluate these factors. Of 801 nesting attempts, 663 were successful, producing a total of 1,613 young. Mean productivity ranged from 1.7 young fledged per nesting attempt in New Jersey to 2.9 in Quebec. Peregrines nesting in quarries or on buildings had higher productivity than those using marsh towers or bridges, but productivity did not differ overall between urban and rural sites. Nests with overhead cover had higher productivity than those without, as did nests in trays or boxes compared to sites without any human-provided nesting aids. Peregrines favored nest sites facing east to south, but productivity did not vary significantly with direction. Several adults have contributed disproportionately to the growth of the eastern population, with just 5 females and males accounting for 8% and 9% of all young fledged, respectively. Of 160 documented mortalities, we identified cause of death for 118, with the most common being collisions with buildings (36%), vehicles (9%), aircraft (8%), and power lines (8%). In many urban areas, grounded fledglings are rescued and returned to higher perches. Of 85 individuals from southern Ontario that were rescued, at least 8 have subsequently bred, producing 65 known offspring. Although peregrines have been thriving in eastern cities, continued management effort may be required for them to maintain their level of success, with key measures including provision of appropriately located nest boxes and rescue of grounded fledglings. © 2014 The Wildlife Society.

Breeding performance and survival in the peregrine falcon Falco peregrinus support an age‐related competence improvement hypothesis mediated via an age threshold

We studied the effects of age on breeding performance and survival probability in a peregrine falcon population, using data from a long term monitoring programme (carried out over 16 yr), in which we were able to identify individual birds. We compared the breeding performance and survival of yearling breeders, first‐time adult breeders and adult breeders. We found significant differences in breeding performance but not in survival. Yearling breeders had lower breeding success than older individuals but the breeding performance of inexperienced adults did not differ from that of experienced adults. We did not find changes in terminal breeding success since peregrines in their last year of life sustained the performance levels shown in previous years although with increasing variability. We found no evidence that attempting to breed affected survival probability in any age group. We argue that differences in breeding performance are related to age, not to breeding experience, and that there is an age threshold, coincident with the development of adult plumage, after which breeding performance is not affected either by age or experience. Peregrines that start breeding as yearlings are likely to have greater lifetime reproductive success than birds entering the breeding pool as adults. Consequently, such birds may represent a set of high quality individuals. Our results support the age‐related competence improvement hypothesis as being the relevant explanation for the increase in breeding performance with age.

Assessing predictions of population viability analysis: Peregrine Falcon populations in California.

Population viability analysis (PVA) has been an important tool for evaluating species extinction risk and alternative management strategies, but there is little information on how well PVA predicts population trajectories following changes in management actions. We tested previously published predictions from a stage-structured PVA of Peregrine Falcons (Falco peregrinus) in California, USA (Wootton and Bell 1992), against population trajectories following the 1992 termination of statewide, active management (population supplementation of captive-reared young). In the absence of extensive post-management monitoring, we developed surrogate estimates of breeding population size by calibrating several citizen science data sets (Christmas Bird Count, CBC; and North American Breeding Bird Survey, BBS) to intensive population surveys taken primarily during the active management period. CBC abundance data standardized by observer effort exhibited a strong relationship to intensive survey data (r2 = 0.971), indicated significantly reduced annual population growth rates after management was terminated (λ = 0.023 ± 0.013 SE) than when supplementation occurred (λ = 0.089 ± 0.023 SE), and demonstrated an increasing population as predicted by the PVA. The population trajectory fell within the 95% CI of stochastic simulations of the model either with or without density dependence and assuming either measurement error or process error, but models with process error were most strongly supported by the data. These results indicate that PVA can quantitatively anticipate population trajectories following changes in management, highlight the importance of post-management monitoring of species of concern, and illustrate the benefits of using management changes as large-scale experiments to more rigorously test PVA.