Hen Harrier Circus Cyaneus Research Articles

Successful reproduction of Hen Harrier Circus cyaneus in intensive arable farmland (central-east Belgium)

Short notes don’t have an abstract.

Migration patterns of breeding Hen Harriers Circus cyaneus in Spain

ABSTRACT Capsule Tracked Hen Harriers Circus cyaneus breeding in Spain winter either in the southern parts of the Iberian Peninsula or in Morocco, although migration timing and distances did not differ between birds using different wintering regions. Aims To study, for the first time, the migratory patterns of Hen Harriers breeding in Spain. Methods Eight breeding adult Hen Harriers were tagged in Spain with GPS/GSM transmitters between 2019 and 2022 to study autumn and spring migration between breeding areas in central or northern Spain, and wintering quarters in southern Spain and Morocco. Results Males and females did not differ significantly in their patterns of migration (dates for start and end of migration, duration, daily distance, and total distance) in either migratory period. Individuals started the autumn migration between July and January, with the peak migration in mid-October. Spring migration took place from February to April and peaked in mid-March. Mean (± sd) distances travelled were: daily distance 168.99 ± 80.10 km/day and total distance 995.07 ± 402.90 km in autumn, and 141.74 ± 41.41 km/day and 1035.26 ± 593.51 km in spring. Two types of migration patterns were found: intra-peninsular migration and migration to Morocco. Migration dates and distances did not differ significantly between individuals with intra-peninsular migration strategies and those migrating to Morocco. Conclusion These results are the first to describe the migratory behaviour of Spanish breeding Hen Harriers using satellite telemetry. Knowledge of migratory routes and behaviour are important for planning the conservation of species.

Morphological study for Accipitrid birds (Accipitridforms, Accipitridae) in Iraq; part two.

A part two of Accipitridae Family members that belong to three genera: Circus, Gyps, and Neophron were documented as morphometrics, distribution ranges, and conservation status were reviewed and comprehensively discussed. A total of 29 voucher specimens belong to six species which are conserved in the "Iraq Natural History Research Center and Museum INHM" as follow: Marsh Harrier Circus aeruginosus (Linnaeus, 1758), Hen Harrier Circus cyaneus (Linnaeus, 1766), Montagus Harrier Circus pygargus (Linnaeus, 1758), Pallid Harrier Circus macrourus (Gmelin, 1770), Egyptian vulture Neophron percnopterus (Linnaeus, 1758), and Griffon vulture Gyps fulfus (Hablitz, 1783). The results revealed significant criteria about near threatened NT species IUCN and Birdlife International listed as Pallid Harrier Circus macrourus, and Endangered (EN) species as Egyptian vulture Neophron percnopterus globally decreasing population trend.

Effect of implementation of irrigation on raptor and corvid populations in a Mediterranean agrosystem

We analyzed changes in the composition of the community of birds of prey and corvids in a rainfed agrosystem after the transformation of 37.2 % of the sampled area into irrigated land between 2005 and 2020. We sampled 57 transects (372 km per year) and fitted generalized linear mixed models (GLMM) to study changes in species occurrence. Our results showed that specific richness and the Shannon index did not vary significantly between rainfed and irrigated transects, but there was a certain positive trend when comparing the years 2005 and 2020. Regarding the differences detected for each species, the occurrence of Montagu’s harrier Circus pygargus, hen harrier Circus cyaneus, Eurasian short-toed eagle Circaetus gallicus, griffon vulture Gyps fulvus and carrion crow Corvus corone was significantly lower in irrigated land than in rainfed land, while magpie Pica pica, Western marsh harrier Circus aeruginosus, common kestrel Falco tinnunculus and black kite Milvus migrans showed a significantly higher occurrence in the irrigated transects. In addition, our findings confirm a significant decrease in occurrence between 2005 and 2020 both in rainfed and irrigated areas for Montagu’s harrier, hen harrier and magpie, while Western marsh harrier, golden eagle Aquila chrysaetos, common buzzard Buteo buteo, red kite Milvus milvus, griffon vulture Gyps fulvus, red-billed chough Pyrrhocorax pyrrhocorax and Western jackdaw Coloeus monedula were detected significantly more frequently in 2020 than in 2005. These results suggest that assessment of the impact of a new irrigation system should focus on the most characteristic species of rainfed agrosystems because the apparently positive effect on other species, equally protected but more generalist, may mask the real effect on conservation.

Impact of wildfires on ecosystems and bird communities on designated areas of blanket bog and heath

ABSTRACT Capsule Wildfires on moorland reduced bird species richness and abundance, along with the seedbank and abundance of ground beetles and spiders. The effects were detectable three years after the fires took place. Aims To describe the effects of wildfires during the breeding season on moorland birds, their habitat and ecosystem characteristics, by comparing burnt with adjacent unburnt areas in six designated sites up to three years post-fire. Methods Point counts of birds, vegetation height and cover, soil seedbank and pitfall traps were used to examine differences between areas burnt by wildfires and unburnt areas. Results One year after wildfire, bird species richness was 50% lower and abundance 32% lower on burnt compared to adjacent unburnt areas. Wildfire burnt areas had 80% of the species richness and 94% of the abundance of unburnt areas three years after wildfire. Bird species associated with upland moorland, including European Stonechat Saxicola rubicola, Common Redshank Tringa tetanus and Hen Harrier Circus cyaneus, were recorded exclusively in unburnt areas. Wildfire burnt areas were characterized by habitat generalist species and community composition in burnt areas remained distinct from unburnt areas three years after burning. Heather Calluna vulgaris and Erica spp. regenerated to 59% of the height of heather on unburnt areas three years after burning. Compared to unburnt areas, burnt areas had a reduced seedbank (22% lower), and reduced ground beetle (15% lower) and spider abundance (31% lower). Conclusion The immediate impacts of wildfire may differ from managed fires due to their indiscriminate character, where they occur, extent, duration and temperature. Wildfire incidence is likely to increase in cool temperate areas due to climate change and likely to undermine the characteristic features of designated areas. Research should focus on preventing wildfires, reducing their impact and accelerating the recovery of burnt moorland.

Illegal killing associated with gamebird management accounts for up to three-quarters of annual mortality in Hen Harriers Circus cyaneus

Predators are frequently victims of wildlife crime due to conflicts with human interests. Where predators are protected, killing may occur covertly and novel methods, including satellite tracking, are often required to assess population consequences. Wildlife crime persists in the British uplands, where raptors are illegally killed on moorland managed for Red Grouse Lagopus lagopus scotica shooting. To understand impacts on one such species, the Hen Harrier Circus cyaneus, we analysed data from 148 individuals tracked across Britain between 2014 and 2021. Using remotely sensed land-use data and continuous-time survival methods, we quantified survival rates, contributions of natural causes and illegal killing to mortality, and spatial and temporal associations between mortality and land managed for grouse shooting. Annual survival was low, especially among first-year birds (males: 14 %; females: 30 %), with illegal killing accounting for 27–43 % and 75 % of mortality in first-year and subadult (1-2 years) harriers respectively. Illegal killing is likely attributable to grouse moor management because i) a 10 % increase in grouse moor use resulted in a 43 % increase in mortality risk; ii) a strong overlap existed between mortality and grouse moor extent in 20 km squares, identifying hotspots of illegal killing in northern England and northeast Scotland; iii) death due to natural causes showed different spatial and temporal patterns; and iv) timing of mortality peaked around the shooting season and during breeding territory establishment. Governments have failed to reduce illegal killing of Hen Harriers and other raptors in Britain and our results emphasise that further legislative reform is needed to tackle this enduring criminality.

Landscape and temporal influences on the winter diet of a threatened diurnal raptor, the Hen Harrier Circus cyaneus

ABSTRACT Capsule Habitat composition plays a key role in determining the winter diet of the Hen Harrier Circus cyaneus, which varies across the winter season and between years. Aims To determine the winter diet of the Hen Harrier and examine temporal and spatial variations in diet composition. Methods A total of 1117 Hen Harrier pellets were collected from 11 winter roosts between 2017 and 2021 in Ireland. Results Hen Harrier winter diet was dominated by avian prey (95.9% of pellets), with mammalian prey found in 12.0% of pellets. The occurrence of small birds and small mammals in the diet was positively associated with the proportion of arable, wild bird cover, and low-intensity agriculture around the roost sites. The frequency of medium-sized birds (primarily Redwing Turdus iliacus and Common Snipe Gallinago gallinago) in the diet was positively associated with the proportion of bog and young conifer forests surrounding roost sites. Diet varied across regions, with pellets from roosts in lowland coastal areas having a greater prevalence of small birds and small mammals, and pellets from roosts in upland areas having a greater prevalence of medium-sized birds. The proportion of medium-sized birds in the diet changed across months, with that of small birds and small mammals remaining stable. There was also variation between winters in the proportion of small- and medium-sized birds in the diet. Conclusions Habitat, along with region and time, are important drivers of variation in Hen Harrier diet. Our findings highlight the opportunity for the enhancement of Hen Harrier habitat through land management, and can be used to inform effective conservation strategies for wintering Hen Harriers at a landscape scale.

Complete mitochondrial genome of a hen harrier Circus cyaneus (Accipitriformes: Accipitridae) from South Korea

A hen harrier Circus cyaneus (Accipitriformes: Accipitridae), a migrant raptor having a wide breeding range from Europe to Northeast Asia, migrates to more southerly areas (Southern Europe, China, Korea and Japan) in winter. In this study, the complete mitochondrial genome of C. cyaneus was completely sequenced and characterized. It was 20,173 bp in length being composed of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and two control regions. It has a base composition of A (32.2%), G (12.6%), C (30.5%) and T (24.7%). The phylogenetic tree reconstructed based on the maximum likelihood (ML) method confirms that C. cyaneus places within the clade of the family Accipitridae in the monophyletic avian order Accipitriformes.

Killing of raptors on grouse moors: evidence and effects

Owing to the intensity of game management in Britain, managers of grouse moors have illegally killed raptors to increase the numbers of Red GrouseLagopus l. scoticaavailable for shooting. This paper summarizes evidence for the recent scale of illegal raptor killing on grouse moors and its effects on populations. It provides insights into how raptors themselves respond demographically to different levels of killing. Over Britain as a whole, most raptors have increased and expanded considerably since the 1970s, in response to reduced killing and nest destruction, and the diminished impacts of organo‐chlorine pesticides; however, in recent decades the populations of some species have declined on and around grouse moors. This is widely evident in Hen HarrierCircus cyaneus, Peregrine FalconFalco peregrinusand Golden EagleAquila chrysaetospopulations and in more restricted areas also in Northern GoshawkAccipiter gentilisand Red KiteMilvus milvuspopulations, in all of which illegal killing has been sufficient to affect numbers over wider areas. The evidence consists mainly of: (1) greater disappearance of nesting pairs, lower breeding densities or reduced occupancy of apparently suitable traditional territories on grouse moors compared with other areas; (2) reduced nest success compared with other areas; (3) reduced adult survival compared with other areas; (4) reduced age of first breeding, reflecting the removal of adults from nesting territories and their replacement by birds in immature plumage; (5) greater levels of disappearance of satellite‐tracked birds on grouse moors than elsewhere; and (6) the finding of poisoned baits and traps, and shot or poisoned carcasses of raptors. Not all these types of evidence are available for every species, and other types of evidence are available for some. The Common BuzzardButeo buteois currently the most numerous raptor in Britain and also seems to be killed in the greatest numbers. Other raptor species, including MerlinFalco columbarius, Common KestrelFalco tinnunculusand Eurasian SparrowhawkAccipiter nisuswhich nest on or near grouse moors, have little or no significant impact on grouse and are killed less often or not at all. In the absence of illegal killing, some raptor species breed as well or better on grouse moors than in other habitats. Merlins, in particular, seem to thrive on grouse moors, benefiting from the management involved (including predator control). Other aspects of illegal raptor killing are discussed, including suggestions for ways in which it might be reduced.

Hen Harrier Circus cyaneus ecology and conservation during the non-breeding season in Ireland

ABSTRACT Capsule A total of 203 Hen Harrier Circus cyaneus winter roosts was recorded in Ireland between 2004 and 2020. The main habitat used for roosting was heath/bog. Burning and land-use change including forestry, agriculture and renewable energy were the most frequent among various pressures and threats recorded. Aims To find and survey Hen Harrier roosts and establish the distribution and habitat associations during the non-breeding season, as well as the conservation issues facing the species during that time. Methods Surveys were undertaken across Ireland each winter from 2004 to 2020, searching for roosts and recording occupancy, behaviour, roost characteristics, pressures and threats. Satellite tracking was also used to locate roosts. Results A total of 203 roosts was recorded, with a widespread distribution. Heath/bog was the most frequently used habitat (53% of roosts), while 53% of roosts were located at less than 100 m above sea level. More than half (52%) of the roosts were communal. The median number of Hen Harriers per roost was 2, the average number was 2.5 and the maximum recorded was 16. Almost a third (31%) of sites documented by this long-term study have become inactive due to anthropogenic pressures. Primary pressures and threats included the disturbance/removal of roosts (e.g. through burning and wind farm development) and changes to the surrounding landscape (e.g. agricultural intensification and afforestation). Conclusion Identifying the distribution, roosts and habitat use of Hen Harriers during the non-breeding season, as well as the prevalent threats and pressures, provides a solid platform on which to base necessary conservation action in Ireland. Supporting landowners to maintain or improve habitats, and taking account of roosts and hunting grounds in assessing proposed developments/land-use change should be considered in any conservation strategy for Hen Harriers.

Fluctuations in field vole abundance indirectly influence red grouse productivity via a shared predator guild

Changes in the abundance of one prey species may indirectly affect other prey species by triggering responses in generalist predators. Here we examine relationships between two prey species that do not compete directly, the field vole Microtus agrestis, a common rodent with fluctuating populations, and the red grouse Lagopus lagopus scotica, a gamebird inhabiting open moorland, during a 27-year study on a moor in south-west Scotland. First, we test whether vole abundance was related to grouse density and demographic rates. Second, we test whether vole abundance was related to abundance indices of four common predators of both voles and grouse (red fox Vulpes vulpes, weasel Mustela nivalis, hen harrier Circus cyaneus and common buzzard Buteo buteo). Third, we test whether these vole–grouse and vole–predator relationships differ in relation to grouse management, which includes the culling of foxes and weasels. We found no association between vole abundance and grouse densities, adult summer survival or nesting success. However, the ratio of young grouse per adult and the proportion of female grouse with broods in July were negatively associated with field vole abundance, suggesting increased predation of grouse chicks in years with high vole abundance. Fox indices showed a weak positive association with vole abundance when their numbers were not controlled, whilst weasel indices showed no relationship with voles. The numbers of breeding hen harriers and buzzards were also not associated with vole abundance, but the number of buzzard sightings was higher when voles were more plentiful. Our results are consistent with a negative interaction between field voles and red grouse chick survival in a pattern expected for apparent competition. Although the underlying mechanisms could not be disentangled, this interaction may be at least partly mediated by rodent-hunting raptors such as buzzards and, in periods without grouse management, foxes.

The influence of habitat edge on a ground nesting bird species: hen harrier Circus cyaneus

Anthropogenic-source habitat fragmentation leads to increased habitat edge in the environment, with potential negative consequences for wildlife. We examine the influence of increased edge on a ground nesting bird of conservation concern, the hen harrier Circus cyaneus. Using eight years of data collected in the Slieve Bloom Mountains Special Protection Area, central Ireland, and an average breeding population of ten pairs, we investigate how habitat fragmentation and edge influences hen harrier nest site selection, breeding success and productivity. We also used a deterministic population matrix model to assess population breeding trends and to simulate population growth rate responses to increased habitat edge by varying demographic parameters such as productivity and juvenile survival. Our results show that habitat edge had a significant effect on nest site selection, breeding success and productivity. Hen harriers were more likely to nest in areas of high edge/area ratio, but this was associated with lower breeding success and productivity, suggesting a possible ecological trap. This mismatch between nest site selection and breeding output may be linked to this species' high reproductive site fidelity. Our population matrix indicated a population increase, whereas population monitoring indicates population stability. Our simulations suggest that increased edge will have a negative effect on population growth rate, providing a greater understanding of the relationship between hen harrier population trends and changing habitat configuration. These results highlight the importance of contiguous habitats and the need for appropriate land use management in protected upland areas for breeding raptors. Minimising habitat fragmentation and forest edge to create larger blocks of uniform peatland habitat should be an integral part of the conservation management of hen harrier breeding areas both in Ireland and in similar breeding habitats such as those in Britain.

Autumn migration of birds over Polonyna Borzhava (Ukrainian Carpathians)

Migration processes of birds occurring on the Polonyna Borzhava ridge were studied. Material was collected during 52-days period since September till November 2018 and total duration of observations was equal to 307 hours. It was found that despite difficult terrain and variable weather conditions at least 48 species of birds migrate over Polonyna Borzhava. Among them the following species dominate: Chaffinch Fringilla coelebs, Common Crane Grus grus, Eurasian Siskin Spinus spinus, Common Wood Pigeon Columba palumbus, Great Tit Parus major, Goldfinch Carduelis carduelis, Water Pipit Anthus spinoletta, Blue Tit Cyanistes caeruleus, and also raptors: Sparrowhawk Accipiter nisus, Common Buzzard Buteo buteo, Goshawk Accipiter gentilis, Hen Harrier Circus cyaneus, Marsh Harrier Circus aeruginosus and other species. Among detected species six are under protection of the Red Data Book of Ukraine: Common Crane, Hen Harrier, Stock Dove Columba oenas, Alpine Accentor  Prunella collaris, Osprey Pandion haliaetus, and Peregrine Falcon Falco peregrinus. Median date of the overall bird passage falls on 9 October. Passage dynamics differs among species. Most of species prefer flight heights not higher than 55 m above the ridge, but some numerous species choose higher altitudes, for instance Wood Pigeon (85.6±62.7 m), and Common Crane (227.5±62.5 m).

Anthropogenic pressures within the breeding range of the Hen Harrier Circus cyaneus in Ireland

ABSTRACTCapsulePatterns in the frequency and co-occurrence of anthropogenic pressures associated with suitable breeding habitat for Hen Harriers Circus cyaneus demonstrates the need for specific, focussed management and policy options aimed at mitigating impacts on this threatened population.AimsTo describe anthropogenic pressures and threats in the upland breeding range of Hen Harriers and to explore their potential impacts on the declining Hen Harrier population.MethodsWe used text mining, mixed-effects models, principal component analysis and clustering methods to explore anthropogenic pressures on suitable breeding and foraging habitats for Hen Harriers in Ireland, based on the 2015 national breeding Hen Harrier survey data.ResultsMixed-effects models described a strong influence of agriculture, forestry, predator activity, and recreational activities on survey areas that contained Hen Harrier territories. Cluster analyses described three discrete pressure clusters and showed consistent co-occurrence of independent pressures.ConclusionsAreas of suitable habitat for Hen Harriers in the uplands overlap with areas that experience anthropogenic pressures known to negatively impact on this vulnerable bird species. Combined with clear evidence for the co-occurrence of multiple pressures at a regional scale, this demonstrates a clear need for statutory agencies to consider the potential cumulative impacts of individual pressures when developing conservation strategies for Hen Harriers.

Factors influencing Hen Harrier Circus cyaneus territory site selection and breeding success

ABSTRACTCapsule: Our findings regarding Hen Harrier Circus cyaneus territory site selection and breeding success in Ireland offer an opportunity for the development of initiatives and conservation actions aimed at enhancing the suitability of upland areas for breeding Hen Harriers and ensuring the long-term persistence of the species.Aims: To investigate landscape-scale associations between habitat composition and Hen Harrier territory site selection, and to explore the influence of habitat and climate on breeding success.Methods: We used multi-model inference from generalized linear models and Euclidean distance analyses to explore the influence of habitat, topographic, anthropogenic and climatic factors on Hen Harrier territory selection and breeding success in Ireland, based on data from national breeding surveys in 2010 and 2015.Results: Hen Harrier territories were associated with heath/shrub, bog and pre-thicket coniferous forests. Comparisons between territories and randomly generated pseudo-absences (upland and lowland) showed that breeding pairs preferentially select for these habitats. Breeding success was negatively influenced by rainfall early in the breeding season and by climatic instability, and was positively influenced by the presence of heath/shrub and bog.Conclusions: The results suggest that Hen Harrier breeding success is compromised by the synergistic effects of climate, landscape composition and management. Effective conservation of Hen Harriers in Ireland will therefore rely on landscape-scale initiatives.

Diversionary feeding and nestling diet of Hen Harriers Circus cyaneus

ABSTRACTCapsule: Diversionary feeding reduced Hen Harrier Circus cyaneus nestlings’ natural food intake by half. Red Grouse Lagopus lagopus scotica chicks constituted 0–4% of all nestling food items. Annually, this reduced annual grouse chick production by 0–6%.Aim: To quantify proportions of diversionary and natural food (including grouse) delivered to Hen Harrier nestlings in relation to brood size, male status and natural prey abundance.Methods: We recorded diversionary food provisioned to 25 Hen Harrier broods (2008–15) and studied the diet of 15 broods using observations from hides, nest cameras and regurgitated pellet analysis. Variation in nestling diet was analysed using compositional analysis.Results: Hen Harriers took 76% of diversionary food provided. Depending on assessment method, average nestling diet was 44–53% diversionary food, 39–55% natural prey (including 24–45% passerines, 4–15% small mammals, 0–4% grouse chicks) and 0–9% unknown items. The amount of diversionary food consumed was not influenced by male status, brood size or natural prey abundance. The number of Red Grouse chicks delivered annually was 34–100% lower than expected under unfed conditions, however, the confidence intervals associated with these estimates were large.Conclusion: Diversionary food influenced Hen Harrier nestling diet and reduced the number of Red Grouse chicks taken relative to modelled predictions. It may help reduce conflict between Hen Harrier conservation and Red Grouse shooting, but only if overall grouse productivity is thereby maintained or increased.

Video Evidence of Siblicide and Cannibalism, Movement of Nestlings by Adults, and Interactions with Predators in Nesting Hen Harriers

During a nest-camera study of Hen Harriers (Circus cyaneus), we recorded siblicide, cannibalism, movement of nestlings by adult birds, and interactions with predators. We deployed cameras at 13 nests across three study areas in Ireland between 2008 and 2010. At a nest with two well-developed nestlings (approximately 25–30 d old), the older nestling killed its sibling and fed on it. This was the first documented case of siblicide in this species, to our knowledge. Recordings also revealed three other events of cannibalism in which one of the nestlings in a brood died from unknown causes and was then eaten by its siblings (n = 1), by the adult male (n = 1), or was used by the adult female to feed the remaining nestlings (n = 1). At two nests, recordings showed the adult female picking up and moving nestlings that were outside the nest cup. In addition, cameras recorded two instances of full brood predation by red fox (Vulpes vulpes) and an attack on a nest by a female Eurasian Kestrel (Falco tinnunculus) that had no apparent consequences for the nestlings or the female Hen Harrier. The behaviors reported here, which are difficult to observe directly, may have important consequences for our understanding of productivity and population dynamics of Hen Harriers.

Status of the Hen Harrier Circus cyaneus in the UK and Isle of Man in 2016

ABSTRACTCapsule: The fifth UK and the Isle of Man survey of Hen Harrier in 2016 showed varying trends by country and region.Aim: To estimate the size of the breeding Hen Harrier population (with associated 95% confidence intervals) in the UK and Isle of Man, constituent countries and Scottish regions, in 2016 and calculate population change over the five surveys to date.Methods: Complete surveys were made of all 10-km squares likely to be occupied by breeding Hen Harriers in England, Wales, Northern Ireland and the Isle of Man, using standard methods developed for previous national surveys. In Scotland, self-selected 10-km squares were surveyed by volunteers and a stratified random selection of the remaining 10-km squares within the known breeding range was surveyed.Results: The UK and Isle of Man Hen Harrier population was estimated at 575 territorial pairs (95% confidence limits, 477–694), a non-significant decline of 13% since 2010 but a significant decline of 24% since 2004. Scotland held the majority (80%) of the population with 460 (359–573) territorial pairs. Elsewhere, 46 territorial pairs were recorded in Northern Ireland, 35 in Wales, 30 in the Isle of Man and four in England. Significant decreases were recorded in the number of pairs in Scotland using grouse moor (−57%) and young forest (−54%).Conclusion: The combined breeding population of Hen Harriers in the UK and Isle of Man has shown a non-significant decline between 2010 and 2016. There were notable decreases in England, Northern Ireland and Wales since 2010.

Hen harrier Circus cyaneus nest sites on the Isle of Mull are associated with habitat mosaics and constrained by topography

ABSTRACTCapsule: Hen Harriers Circus cyaneus on the Isle of Mull, UK, are associated with habitat mosaics consisting of moorland, scrub and forestry but avoid grazed land, suggesting that forested habitats could be managed sympathetically for the Hen Harrier in the future should the current UK population increase.Aims: To use distribution modelling to investigate nesting habitat associations using a long-term data set for the Hen Harrier on Mull.Methods: We develop area-interaction models using a least absolute shrinkage and selection operator penalty to explore the distribution of 102 Hen Harrier nest sites in relation to habitat and topography. Our model is then successfully validated in tests using data for 70 nest sites from subsequent years.Results: Our model is effective in predicting suitable areas for Hen Harrier nest sites and indicates that Hen Harriers on Mull are found in habitat mosaics below 200 m above sea level. Hen Harrier nest intensity is positively associated with increasing proportions of moorland and scrub, open canopy forestry and closed canopy forestry. Nest intensity is negatively associated with increasing proportions of grazed land.Conclusion: Hen Harriers avoid grazed areas but are relatively tolerant of other habitat combinations. These findings are supported by previous observations of Hen Harrier habitat use and have implications for the recovery of some Hen Harrier populations in Special Protection Areas and future forest management. Open canopy forest and forest mosaics could potentially be incorporated into landscape-scale conservation plans for Hen Harriers using the population on Mull as an example.

Activity patterns of breeding Hen Harriers Circus cyaneus assessed using nest cameras

ABSTRACTNest camera footage from 13 Hen Harrier Circus cyaneus nests was analysed to document patterns of adult attendance, incubation, brooding and prey delivery rates. Nest attendance was high throughout the incubation stage and began to decrease when chicks were five days old. Chick provisioning increased gradually after hatching and peaked when the chicks were five days old. Daily activity rates were highest during the middle of the day, from 08:00 to 19:00 hours.