Peregrine Research Articles

Northerly dispersal trends in a lowland population of Peregrines Falco peregrinus in southwest England

ABSTRACT Little is known about the post-natal dispersal of Peregrines Falco peregrinus from lowland areas of England. We used the resighting and recovery data from 66 Peregrine nestlings (34 females, 32 males) colour-ringed in the southwest of England to outline their reported dispersal movements. Our results revealed that Peregrines, in particular females, disperse in a north-northeasterly direction, with females being resighted at greater distances than males. Males were resighted a mean of 44 km from their natal site and females significantly further (mean 117 km). Despite more recent local and regional declines in some areas of their UK range, Peregrines have been increasing at a national level in England and extending their breeding range into new areas. Our results indicate that Peregrines have the potential to continue occupying suitable vacant habitats across the UK. Dispersing birds from the southwest of England are potentially helping to increase the breeding population of Peregrines in other areas where they have been absent or scarce for many years.

The presence of pathogens and heavy metals in urban peregrine falcons (Falco peregrinus).

Background and Aim:Wild birds raised in urban environments may be exposed to many negative factors, including biological and chemical toxic elements. The aim of the study was to assess the occurrence of bacteria and parasites in wild birds, based on the example of the peregrine falcon (Falco peregrinus) as a potential indicator of bacterial drug resistance genes. Toxicological contamination was also analyzed to determine the impact of urbanized areas on this predatory species, in terms of its health, welfare, and survival in urban environments.Materials and Methods:The samples consisted of down feathers and fresh feces obtained from seven falcon chicks (during obligatory veterinary examination) reared in two nests located in the Lublin region (Lublin and Puławy). Bacteria and parasites were isolated directly from feces by classical microbiological methods, polymerase chain reaction, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS). The down feathers and feces of birds were used for toxicological testing by plasma inductively coupled plasma MS to assess the concentrations of selected heavy metals (cadmium [Cd], lead [Pb], arsenic [As], zinc [Zn], and copper [Cu]).Results:The study revealed the presence of a diverse microbiome in the falcon chicks, among which Escherichia coli, Enterococcus spp., and Staphylococcus spp. bacteria and parasites of the genus Caryospora were dominant. The presence of drug resistance genes was also confirmed among the pathogens. The toxicological analysis found high concentrations of toxic heavy metals, including Cd, Pb, As, and Zn, in the downy feathers and feces of peregrine chicks.Conclusion:Predatory free-living birds living in urban environments not only can be infected with various pathogens but may also show contamination with heavy metals, which could influence their natural resistance, condition, and welfare.

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A total of 45 voucher specimens of falcons which are deposited in the bird's collection of the Iraq Natural History Research Center and Museum (INHM) were reviewed. Mummified falcons were preserved as voucher study specimens and tagged with museum collection labels. In the current study, morphometrics of six species of the genus Falco Linnaeus, 1758: Lanner falcon F. biarmicus Temminck, 1825; Sacker Falcon F. cherrug Gray, 1834; Lesser Kestrel F. naumanni Fleischer, 1818; Peregrine Falcon F. peregrines Tunstall, 1771; Eurasian Hobby F. subbuteo Linnaeus, 1758 and Common Kestrel F. tinnunculus Linnaeus, 1758 were documented. These species were recorded previously in the ornithological literatures by several authors and deposited in the museum collection; nevertheless, breeding and migrating of these birds are still occurring throughout Iraq. Furthermore, the current distribution ranges and conservation status of each of the mentioned species throughout Iraq were reviewed and comprehensively discussed.

Massively parallel sequencing and capillary electrophoresis of a novel panel of falcon STRs: Concordance with minisatellite DNA profiles from historical wildlife crime

Birds of prey have suffered persecution for centuries through trapping, shooting, poisoning and theft from the wild to meet the demand from egg collectors and falconers; they were also amongst the earliest beneficiaries of DNA testing in wildlife forensics. Here we report the identification and characterisation of 14 novel tetramer, pentamer and hexamer short tandem repeat (STR) markers which can be typed either by capillary electrophoresis or massively parallel sequencing (MPS) and apply them to historical casework samples involving 49 peregrine falcons, 30 of which were claimed to be the captively bred offspring of nine pairs. The birds were initially tested in 1994 with a multilocus DNA fingerprinting probe, a sex test and eight single-locus minisatellite probes (SLPs) demonstrating that 23 birds were unrelated to the claimed parents. The multilocus and SLP approaches were highly discriminating but extremely time consuming and required microgram quantities of high molecular weight DNA and the use of radioisotopes. The STR markers displayed between 2 and 21 alleles per locus (mean = 7.6), lengths between 140 and 360 bp, and heterozygosities from 0.4 to 0.93. They produced wholly concordant conclusions with similar discrimination power but in a fraction of the time using a hundred-fold less DNA and with standard forensic equipment. Furthermore, eleven of these STRs were amplified in a single reaction and typed using MPS on the Illumina MiSeq platform revealing eight additional alleles (three with variant repeat structures and five solely due to flanking SNPs) across four loci. This approach gave a random match probability of < 1E-9, and a parental pair false inclusion probability of < 1E-5, with a further ten-fold reduction in the amount of DNA required (~3 ng) and the potential to analyse mixed samples. These STRs will be of value in monitoring wild populations of these key indicator species as well as for testing captive breeding claims and establishing a database of captive raptors. They have the potential to resolve complex cases involving trace, mixed and degraded samples from raptor persecution casework representing a significant advance over the previously applied methods.

Habitat preferences of diurnal raptors in relation to human access to their breeding territories in the Balkan Mountain Range, Bulgaria

BackgroundIn this study we examined the habitat preferences of three diurnal raptors in relation to human access. We aimed to identify the selection of breeding habitat by the Golden Eagle (Aquila chrysaetos), the Long-legged Buzzard (Buteo rufinus), and the Peregrine Falcon (Falco peregrinus) in response to site accessibility by humans, and in turn, the response of these species to human presence.MethodsData about the nest locations were collected. Analyses and maps were created using ArcGIS. The “least cost path” was defined using the Cost Path tool.ResultsThe lowest values of the Cost Path were established for Long-legged Buzzard and the highest values were estimated for Golden Eagle. Intermediate Cost Path values for Peregrine Falcon were found.ConclusionsThe Long-legged Buzzard could be considered as the most tolerant to human presence in its breeding territories. The Golden Eagle have the lowest degree of tolerance and the Peregrine Falcon is ranked in an intermediate position compared to the other two species, but closer to Golden Eagle.

Can shorebirds use heterospecifics as cues of danger? An observation of Willets gathering around a Peregrine Falcon consuming a godwit

Can shorebirds use heterospecifics as cues of danger? An observation of Willets gathering around a Peregrine Falcon consuming a godwit

Effect of Nesting Substrate on the Breeding Performance of Peregrine Falcons in Guerrero Negro, Baja California Sur, Mexico, 2012–2016

The Peregrine Falcon (Falco peregrinus) breeds locally in the Guerrero Negro wetland complex, Baja California Sur, Mexico, but the most recent investigation of their breeding ecology in this wetland area was in 1998. Our objectives were to update the information on the reproduction of Peregrine Falcons in Guerrero Negro and to evaluate the relationship of reproductive parameters with the environmental temperature, rainfall, and nest substrate (natural or artificial). From 2012 to 2016 we surveyed for Peregrine Falcon nests, and monitored them from February to May each year. We recorded the type of nest substrate (natural or artificial) and the nest contents (eggs, nestlings, or fledglings) at every visit. Pooled across years, we recorded 34 reproductive events that produced 42 fledglings. On average per year, there were 6.8 ± 1.6 egg-laying pairs, and 4.4 ± 1.8 were successful, with a productivity of 1.23 ± 0.06 fledglings/egg-laying pair. Monthly mean air temperatures and rainfall had no effect on breeding parameters; however, there were significant relationships with type of nest substrates. On average, we found falcons had greater nesting success and productivity on artificial substrates (83 ± 15% and 1.91 ± 0.12 fledglings/egg-laying pair) than on natural substrates (36 ± 21% and 0.36 ± 0.21 fledglings/egg-laying pair). Compared to the 1998 estimate, the number of egg-laying pairs in Guerrero Negro has more than doubled (from four to nine); this wetland area currently holds the largest number of breeding pairs along the Baja California Peninsula.

Nontarget Screening of Organohalogen Compounds in the Liver of Wild Birds from Osaka, Japan: Specific Accumulation of Highly Chlorinated POP Homologues in Raptors.

Nontarget screening studies have recently revealed the accumulation of typically unmonitored organohalogen compounds (OHCs) in various marine animals, but information for terrestrial food chains is still lacking. This study investigated the accumulation profiles of known and unknown OHCs in the liver of representative wild bird specimens from Osaka, Japan using nontarget analysis based on two-dimensional gas chromatography-time-of-flight mass spectrometry. A large number of unmonitored OHCs were identified, including anthropogenic contaminants and marine halogenated natural products (HNPs), and their accumulation profiles were considered to be influenced by terrestrial and brackish water-based diets. Anthropogenic OHCs were highly accumulated in terrestrial predator species (peregrine falcon, hawks, and black kite), and some unmonitored highly chlorinated contaminants reached the levels of microgram per gram lipid in the liver, i.e., C10-/C15-based chlordane related compounds (CHLs) and their epoxides, dichlorodiphenyldichloroethylene (DDE) homologues, and polychlorinated terphenyls (PCTs). In contrast, HNPs were accumulated at higher levels in piscivorous birds (gray heron and common cormorant). Considering the enrichment of the unmonitored C10-/C15-based CHLs, PCTs, and DDE homologues relative to structurally similar persistent organic pollutants (POPs) in high trophic-level species such as raptors, further studies are needed to elucidate their environmental levels, behavior in terrestrial food chains, and ecotoxicological impacts.

Absence of “selfish herd” dynamics in bird flocks under threat

The "selfish herd" hypothesis1 provides a potential mechanism to explain a ubiquitous phenomenon in nature: that of non-kin aggregations. Individuals in selfish herds are thought to benefit by reducing their own risk at the expense of conspecifics by attracting toward their neighbors' positions1,2 or central locations in the aggregation.3-5 Alternatively, increased alignment with their neighbors' orientation could reduce the chance of predation through information sharing6-8 or collective escape.6 Using both small and large flocks of homing pigeons (Columba livia; n= 8-10 or n= 27-34 individuals) tagged with 5-Hz GPS loggers and a GPS-tagged, remote-controlled model peregrine falcon (Falco peregrinus), we tested whether individuals increase their use of attraction over alignment when under perceived threat. We conducted n= 27 flights in treatment conditions, chased by the robotic "predator," and n= 16 flights in control conditions (not chased). Despite responding strongly to the RobotFalcon-by turning away from its flight direction-individuals in treatment flocks demonstrated no increased attraction compared with control flocks, and this result held across both flock sizes. We suggest that mutualistic alignment is more advantageous than selfish attraction in groups with a high coincidence of individual and collective interests (adaptive hypothesis). However, we also explore alternative explanations, such as high cognitive demand under threat and collision avoidance (mechanistic hypotheses). We conclude that selfish herd may not be an appropriate paradigm for understanding the function of highly synchronous collective motion, as observed in bird flocks and perhaps also fish shoals and highly aligned mammal aggregations, such as moving herds.

Malar stripe size and prominence in peregrine falcons vary positively with solar radiation: support for the solar glare hypothesis

Many falcons (Falco spp.) exhibit a distinct dark plumage patch below the eye, termed the malar stripe. This stripe is hypothesized to reduce the amount of solar glare reflected into the eyes while foraging, thereby increasing hunting efficiency in bright conditions. Here, we use a novel, global-scale correlative approach to test this 'solar glare hypothesis' in peregrine falcons (Falco peregrinus), the most widespread falcon species, using web-sourced photographs from across the species' global range. We found that the size and prominence of the malar stripe were positively associated with average annual solar radiation, but not with other environmental variables, such as temperature and rainfall. Our results provide the first published evidence for the hypothesis that this plumage feature functions to reduce the amount of solar glare reflected into the falcon's eyes, thereby improving the ability to pinpoint and target agile prey in bright conditions.

A true desert falcon with a delayed onset of heat dissipation behaviour

The Grey Falcon (Falco hypoleucos) is a rare Australian endemic bird of prey confined for its entire life to the continent's hot arid and semi-arid zone. The prevention of hyperthermia is therefore a crucial challenge. Birds, in general, rely on a dynamic balance between physiological mechanisms and the behaviours that augment them. Effective heat dissipation behaviours in birds include panting, airing and shade-seeking. These behaviours are readily observable in the field. We observed Grey Falcons, Peregrine Falcons (F. p. peregrinus and F. p. macropus) and Saker Falcons (F. cherrug) in the wild (from continuous webcam video for the latter two species) and compared their heat dissipation behaviours in relation to air temperature, exposure to direct solar radiation, wind speed, and relative humidity. Our results show that the desert-living Grey Falcon has a considerably higher heat dissipation behaviour threshold than the two non-desert Falco species. We show that this leads to the prediction that Grey Falcons should have reduced average activity levels in key aspects of their lives, throughout the year, relative to their congeners.

Disease surveillance in England and Wales, April 2021

Disease surveillance in England and Wales, April 2021

Assessment of the Genetic Potential of the Peregrine Falcon (Falco peregrinus peregrinus) Population Used in the Reintroduction Program in Poland.

Microsatellite DNA analysis is a powerful tool for assessing population genetics. The main aim of this study was to assess the genetic potential of the peregrine falcon population covered by the restitution program. We characterized individuals from breeders that set their birds for release into the wild and birds that have been reintroduced in previous years. This was done using a well-known microsatellite panel designed for the peregrine falcon containing 10 markers. We calculated the genetic distance between individuals and populations using the UPGMA (unweighted pair group method with arithmetic mean) method and then performed a Principal Coordinates Analysis (PCoA) and constructed phylogenetic trees, to visualize the results. In addition, we used the Bayesian clustering method, assuming 1–15 hypothetical populations, to find the model that best fit the data. Units were segregated into groups regardless of the country of origin, and the number of alleles and observed heterozygosity were different in different breeding groups. The wild and captive populations were grouped independent of the original population.

Lice, Flies, Mites, and Ticks on Raptors (Accipitriformes, Falconiformes and Strigiformes) in Rescue Centers in Central Italy

This study aims to assess the occurrence of external arthropods on deceased raptors in rescue centers in Tuscany, central Italy. The examined diurnal raptors include 17 common buzzards (Buteo buteo), two European honey buzzards (Pernis apivorus), seven sparrowhawks (Accipiter nisus), six common kestrels (Falco tinnunculus), a western osprey (Pandion haliaetus), and a peregrine falcon (Falco peregrinus). Nocturnal raptors included seven barn owls (Tyto alba), ten tawny owls (Strix aluco), 22 little owls (Athene noctua) and two scops owls (Otus scops). The skin and the feathers of each animal were examined, and arthropods were collected, fixed, and microscopically identified. In 48 out of the 75 examined birds (64%), at least a single arthropod species was found. Identified arthropods included chewing lice (Degeeriella fulva, D. rufa, Colpocephalum turbinatum, C. apivorus, Nosopon lucidum, N. clayae, Craspedorrhyncus platystomus, Laemobothrion tinnunculi, Kurodaia subpachygaster, Strigiphilus cursitans), hippoboscid flies (Ornithomya avicularia), chigger and feather mites (Kramerella lunulata, K. lyra, Kramerella sp., Glaucalges attenuatus, Hieracolichus nisi, Hieracolichus sp., Neotrombicula autumnalis) and ticks (Haemaphysalis sp.). Most of the identified mite, fly and tick species are the first records in raptors in Italy. Moreover, this study presents the first record of Hieracolichus sp. and N. autumnalis mites in P. haliaetus and F. tinnunculus, respectively.

South African raptors in urban landscapes: a review

Globally, but especially in Africa, increasing human populations and anthropogenic land-use change are generally affecting diversity negatively. Urban environments in southern Africa typically comprise a mosaic landscape of anthropogenic infrastructure with some green spaces. These urban cities have a range of fauna that have persisted or increased in population density compared with areas that are more natural. We analysed the occurrence of diurnal and nocturnal raptors using South African Bird Atlas Project (SABAP2) data and reviewed literature. We found 66 raptor species occurred in South African cities. Thirty species had reporting frequencies greater than 10% in at least one of the 11 cities assessed, revealing impressive diversity of the raptor clade in South African cities. Five species were both abundant and widespread, occurring >10% in five or more cities each, of which three belong to the scavenger guild: Black-winged Kite Elanus caeruleus, African Fish Eagle Haliaeetus vocifer, Common Buzzard Buteo buteo vulpinus, Yellow-billed Kite Milvus aegyptius and Black Sparrowhawk Accipiter melanoleucus. However, only a few of these 66 raptors had been extensively studied in urban areas: the Black Sparrowhawk, African Crowned Eagle Stephanoaetus coronatus, Lanner Falcon Falco biarmicus and Peregrine Falcon Falco peregrinus. This lack of research is specifically severe, given that Africa is hosting a unique and diverse range of raptor species and that numbers and diversity of raptors have declined dramatically over the past decades across the continent. In fact, these four extensively studied species occurred in higher densities in urban areas than rural areas, which indicates that urban areas might create valuable opportunities for urban conservation, not least through public engagement.

Tracking peregrine falcon flight paths

Tracking peregrine falcon flight paths

Climate-driven flyway changes and memory-based long-distance migration.

Millions of migratory birds occupy seasonally favourable breeding grounds in the Arctic1, but we know little about the formation, maintenance and future of the migration routes of Arctic birds and the genetic determinants of migratory distance. Here we established a continental-scale migration system that used satellite tracking to follow 56peregrine falcons (Falco peregrinus) from 6populations that breed in the Eurasian Arctic, and resequenced 35genomes from 4of these populations. The breeding populations used five migration routes across Eurasia, which were probably formed by longitudinal and latitudinal shifts in their breeding grounds during the transition from the Last Glacial Maximum to the Holocene epoch. Contemporary environmental divergence between the routes appears to maintain their distinctiveness. We found that the gene ADCY8 is associated with population-level differences in migratory distance. We investigated the regulatory mechanism of this gene, and found that long-term memory was the most likely selective agent for divergence in ADCY8 among the peregrine populations. Global warming is predicted to influence migration strategies and diminish the breeding ranges of peregrine populations of the Eurasian Arctic. Harnessing ecological interactions and evolutionary processes to study climate-driven changes in migration can facilitate the conservation of migratory birds.

Attack behaviour in naive gyrfalcons is modelled by the same guidance law as in peregrine falcons, but at a lower guidance gain.

ABSTRACTThe aerial hunting behaviours of birds are strongly influenced by flight morphology and ecology, but little is known of how this relates to the behavioural algorithms guiding flight. Here, we used GPS loggers to record the attack trajectories of captive-bred gyrfalcons (Falco rusticolus) during their maiden flights against robotic aerial targets, which we compared with existing flight data from peregrine falcons (Falco peregrinus). The attack trajectories of both species were well modelled by a proportional navigation (PN) guidance law, which commands turning in proportion to the angular rate of the line-of-sight to target, at a guidance gain N. However, naive gyrfalcons operate at significantly lower values of N than peregrine falcons, producing slower turning and a longer path to intercept. Gyrfalcons are less manoeuvrable than peregrine falcons, but physical constraint is insufficient to explain the lower values of N we found, which may reflect either the inexperience of the individual birds or ecological adaptation at the species level. For example, low values of N promote the tail-chasing behaviour that is typical of wild gyrfalcons and which apparently serves to tire their prey in a prolonged high-speed pursuit. Likewise, during close pursuit of typical fast evasive prey, PN will be less prone to being thrown off by erratic target manoeuvres at low guidance gain. The fact that low-gain PN successfully models the maiden attack flights of gyrfalcons suggests that this behavioural algorithm is embedded in a guidance pathway ancestral to the clade containing gyrfalcons and peregrine falcons, though perhaps with much deeper evolutionary origins.

Novice gyrfalcons cut straight to the kill on maiden flight

Prized for their rarity during the Middle Ages and designated the bird of kings by medieval gentlemen, gyrfalcons may even have instigated the downfall of a Chinese empire, thanks to its demand for the merciless hunters. Gyrfalcons carry a majestic cachet, yet it wasn't clear whether these masters of the air are unique or use the same interception strategy as other falcons when closing in for the kill; they rarely swoop from spectacular heights to intercept prey like their smaller cousin, the peregrine falcon. According to Caroline Brighton from the University of Oxford, UK, ‘Wild gyrfalcons are most often recorded performing low surprise attacks initiated from a perch or from ridge soaring’. Knowing that Harris’ hawks hound their victim from behind, Brighton and her colleagues, Katherine Chapman (University of Oxford), Nicholas Fox (Wingbeat Ltd) and Graham Taylor (University of Oxford) wondered whether gyrfalcons use a hawk-like strategy, where they directly follow every twist and turn of their prey, or apply their peregrine cousin's strategy, cutting the corner off their approach and aiming ahead of their prey to intercept it. Puzzled by the mystery of the regal raptors, the team decided to investigate how novice gyrfalcons that had never pursued prey before tackled the interception challenge.‘Nick breeds gyrfalcons for falconry and he invited us to watch the training flights of his latest cohort of juvenile birds at their training grounds’, says Brighton, who joined Fox and the rest of the team in the north of England for the young birds’ maiden flights. ‘Northumberland has large expanses of open moorland, much better suited for flying drones and falcons’, Brighton explains. With each bird hooded and perched on its handler's glove, a drone pilot moved into position upwind of the young gyrfalcon with a remote controlled aeroplane disguised as a crow, known as a Rocrow. As soon as the handler removed the hood, the gyrfalcon set off in pursuit of the fleeing crow robot. ‘The pilot flew the Rocrow through a series of evasive turns and the trial ended when the falcon either touched or grabbed it with its talons’, says Brighton. Filming 20 skirmishes while tracking the robot prey and birds’ manoeuvres in fine detail with GPS loggers, the researchers were able to recreate each airborne duel back in the lab. They then simulated a range of dog fight styles, from the peregrine falcon's interception approach to the Harris’ hawk's hot pursuit, to find out which strategy most closely replicated the gyrfalcons’ flight path.Analysing 111 s of the birds’ intricate flight paths as they hunted their quarry over 1127 m in total, Brighton and Taylor successfully reproduced the bird's manoeuvres by recreating a variant of the peregrine falcon's interception approach, resulting in the gyrfalcon's signature tail-chase strategy. However, the inexperienced gyrfalcons were not as nimble as the smaller peregrine falcons, turning more slowly and pursuing their quarry farther before grasping it with their talons. Brighton and Taylor suggest that although the gyrfalcon's strategy is less efficient than the peregrine's, the prolonged chase allows them to harry their wild prey to exhaustion.The fact that gyrfalcons on their maiden flights were able to perform such meticulous interceptions with no practice suggests that they inherit the ability and cut straight to the kill without having to learn from other birds. The team's discovery that the gyrfalcon's interception flight path has more in common with that of their peregrine falcon cousins also suggests that these attack behaviours may be characteristic of all falcons and were practised by the last ancestor that the two species had in common.

Contrasting long‐term trends in age‐specific survival of Peregrine Falcons (Falco peregrinus) in Britain using smoothed estimates of recovery probabilities

Peregrine Falcons Falco peregrinus are an iconic species of long‐standing conservation concern as a result of historical patterns of persecution and dramatic pesticide‐related population declines in many populations during the second half of the 20th century. Although the role of reduced productivity in these declines is well known, the temporal patterns in survival are much less well characterized. We estimate survival probabilities for Peregrines in Britain in the period 1975–2018 from reports of ringed birds found dead, using a non‐parametric smoothing spline to account for non‐linear temporal variation in recovery probabilities. During this time the population increased from around 350 pairs to 1628 pairs. There was little evidence of a temporal trend in the survival probabilities of adult birds since the mid‐1970s, but survival of first‐year birds appears to have decreased. Our estimates suggest that increases in the breeding population are further limited by unreported sources of mortality or by density‐dependent processes, highlighting the need for better data on immature survival and recruitment. Modelling recovery rates using a spline, rather than independent annual values, improved estimation efficiency with lower credible intervals obtained for the adult annual estimates.