https://orcid.org/0000-0002-6196-9160
Figures
Abstract
Raptors are highly sensitive to environmental and human-induced changes. In addition, several species of raptors exist in considerably small numbers. It is thus critical to conserve raptors and their habitats across relatively larger landscapes. We examined the diurnal raptor assemblages and seasonality in a subtropical habitat in India’s northwestern Himalayas. Quantitative data on diurnal birds of prey and their habitat features across six distinct habitat types were collected from 33 sample sites. We observed 3,434 individuals of 28 diurnal raptors belonging to two orders and three families during a two-year survey from December 2016 to November 2018. A significant variation in bird species richness and abundance was found across habitats and seasons, with farmlands and winters being the most diverse and speciose. The generalized linear model, used to determine raptor community responses, indicated that elevation and proximity to dumping sites significantly affected the raptor abundance. The non-metric multidimensional scaling (NMDS) revealed significant differences in raptor assemblages across the habitat types. The study concluded that raptors’ persistence is largely determined by their preference for favourable feeding, roosting, and nesting opportunities. The presence of protected and habitat-exclusive species validates the high conservation importance of these ecosystems, particularly the forest patches and farmlands, necessitating robust conservation and management measures in this part of northwestern Himalaya.
Citation: Kumar S, Sohil A, Kichloo MA, Sharma N (2022) Landscape heterogeneity affects diurnal raptor communities in a sub-tropical region of northwestern Himalayas, India. PLoS ONE 17(4): e0246555. https://doi.org/10.1371/journal.pone.0246555
Editor: Bhoj Kumar Acharya, Sikkim University, INDIA
Received: January 20, 2021; Accepted: January 22, 2022; Published: April 28, 2022
Copyright: © 2022 Kumar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper and its Supporting Information files.
Funding: The author(s) received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
Introduction
With growing concerns about the changing land-use patterns, monitoring changes in the biological integrity of ecosystems has become essential [1], which may be accomplished using appropriate indicator species [2]. Raptors are considered excellent bio-indicators of habitat quality [3–5], environmental health [6, 7], and ecological imbalances [5, 8], and their existence is linked with a high level of biodiversity [4, 9]. Present in majority of ecosystems world over, although in very small numbers, they play a crucial role in organizing biological communities [10, 11] and promoting ecological stability [12]. However, a lack of information on the status, distribution, and ecological needs of raptors worldwide [13–15] hampers the conservation efforts [14, 16]. Raptors are particularly susceptible to human disruptions owing to their life-history characteristics, low population densities, large home ranges [17–19], and high trophic levels [4, 20]. Further, the environmental contamination [17] and habitat degradation [16, 21] exacerbate the rate of extinction [22], which is high among the raptors. Nonetheless, the adaptation of some raptors to human-altered environments places their candidature controversial as an indicator [23, 24].
Both high habitat heterogeneity and prey diversity contribute to species richness and abundance among the raptor communities [25], since species-environment interactions are largely determined by habitat types and their selection [26, 27]. Raptors require relatively large areas for effective hunting and nesting [28, 29], apart from avoiding human persecution. The understanding of biotic interactions, ecological affinities [30], and population dynamics of raptors provide valuable information about their habitats [7, 27, 31–35], enabling their optimal management and conservation [30, 36–38]. The avian diversity is linked to several environmental factors [39–41], most notably habitat [26] and seasonality, which determine the diversity and dynamics, including migrations in a variety of ecoregions [27, 35, 42–44]. Dietary preferences, habitat specializations, and migratory behavior significantly affect the distribution and richness of species across a vast geographical area [45].
Despite their charisma and immense ecological importance, there is no comprehensive global assessment of the status, threats, and protection of all raptors [46]. Their low population densities, slow turnover rates [6, 22, 47], and high susceptibility to anthropogenic stressors [4, 20] contribute to substantial population decline [48]. Other major limiting factors include habitat alteration [13, 14, 49–54], extermination [55, 56], poisoning [57–63], electrocution [64–67], collisions with man-made structures and vehicles [6, 68, 69], road kills [70], human consumption [71, 72], feral dog depredation [73], and climate change [74–79]. In addition, they are likely to become victims of expanding agriculture and logging globally [80, 81]. The majority of raptors, especially diurnal birds of prey, are the most vulnerable species [6], facing challenges throughout Europe [82, 83], Asia, the Middle East, and Africa [84–86]. Moreover, 127 of the world’s 333 species of diurnal birds of prey are found in Asia, 101 in the Indo-Malayan area, and 74 in India [87]. The erstwhile state of Jammu and Kashmir is home to 46 raptors [88], accounting for 62% of all birds of prey in India.
As much of the information comes from short-term studies [88–92] and opportunistic observations [93], data on functional traits and ecology of this largest avian group is scarce for the region [88]. Given the region’s relative lack of knowledge on raptor communities, we aimed to examine, how and to what degree their assemblages (distribution, abundance, and habitat associations) react to localized environmental characteristics and seasonality in various habitat types. During the two-year study, we predicted a pronounced variation in the raptor community structure (abundance, richness, composition) in open areas (with high chances of raptors sightings) and during winters (with the seasonal flocking by migrants). The study was conducted in Jammu Shivaliks, a southerly sub-tropical region in the Union Territory (UT) of Jammu and Kashmir.
Material and methods
Study area
The study area forms a complex heterogeneous land cover consisting of forests, fallow lands, agricultural fields, urban built-up areas, urban green spaces, and a variety of aquatic systems (S1 Appendix, Fig 1). Intended to cover a range of diverse habitats, the surveys were delimited to 33 sampling sites (micro-habitats) with varying degrees of disturbances (S1 Appendix). The sampling sites were classified as undisturbed forests (that included pristine mixed broadleaved forest, dry scrub, and riparian patches), forest farmland interfaces (edges between the forests and agriculture fields), farmlands (vast agricultural fields and fallow land), urban built-up areas (residential areas, including suburbs), green belts and urban avenue plantations (parks, gardens, roadside trees, remnant woodlands, plantations, and greenways), and water bodies and buffer zones that included seasonal and perennial ponds, streams, and rivers. The sampling was performed in four distinct seasons, summer (March–May), monsoon (June–September), post-monsoon (October–November), and winter (December–February) from December 2016 to November 2018.
The colored lines denote the sample clusters for each habitat type, which include road and line transects, while the symbols represent vantage points (refer S1 Appendix for details). All the spatial attributes were collected and prepared by the authors for the visualization purpose using open source QGIS; no copyrighted material was used.
Topography and land use
The study area lies among the tertiaries and is comprised of two distinct geological formations, the Shivaliks and the alluvial plains, which serve as the northwestern extension of the Indo-Gangetic Plains. The Shivalik system, consisting of moderately elevated hills, is sedimentary in nature, dividing it into upper, middle, and lower zones. The region is drained by Chenab, Ravi, Tawi, Ujh, and Basanter as well as several seasonal streams locally known as Khads. The area is dotted with twin lakes, Surinsar and Mansar (both of which are Ramsar sites), reservoirs (Ranjitsagar and Ujh impoundment), and numerous wetlands, and seasonal and perennial ponds. Forests cover 38% of the geographical area, followed by agriculture (26%), open fallows (23%), grasslands (11%), and water bodies (2%).
Sampling design and data collection
Diurnal raptors were recorded following the method described by Fuller and Mosher [94], Millsap and LeFranc [95], Whitcare and Turley [96], Austin et al. [97], and Bibby and Burgess [98]. We relied heavily on road surveys, which are the most effective methods for describing raptor assemblages, distribution, abundance, and habitat preferences [94, 99]. Each road transect spanned 3–7 kms and was traveled in a vehicle at a maximum speed of 20 km/h. The plains, farmlands, and undisturbed forests were sampled by setting up line transects and vantage points (point counts). The line transects (0.75–1.5 km each) were walked on foot at least twice a month during the entire sampling period. Each survey included teams of two to three observers. The vantage points were established in high locations to count flying raptors within a radius of 1–2 km. To prevent duplicate counting, the road and line transects were separated by at least 5–7 kms and 1 km, respectively. A total of 36 road transects, 19 line transects, and 80 vantage points were sampled in six different habitat types in the study area (S1 Appendix). For each transect, the number of species and individuals observed, activity, and habitats occupied were recorded. The sampling intensity, i.e., the number and length of transects, was justified in relation to the area occupied by diurnal raptors and their likelihood of occurrence. The surveys were performed in the mornings (9 a.m.–12 p.m.) and afternoons (3:30 p.m.–5:30 p.m.), which coincided with a time of high raptor activity [100]. Sampling was avoided during bad weather. A few opportunistic sightings near the specified sample sites were also included in the analysis. Observations were made using 10 × 50 binoculars and a Canon EoS 7D Mark II DSLR equipped with a 100 × 400 mm telephoto lens. The species observed were identified using standard field guides [101–103].
Functional traits and conservation status
Raptors have been classified as predators (that hunt, kill, and eat their prey) or carrion feeders (that feed on the dead animal matter) based on their dietary choices and foraging behavior. For each site, the habitat guild (whether a generalist or specialist) and seasonal status, including whether it is a year-round resident, a summer or winter resident, for each species, was determined. The information on functional traits was extracted from De Graaf et al. [104] and The Cornell Lab of Ornithology [105]. The species’ conservation status was obtained from the IUCN Red List of Threatened Species [106].
Data analysis
Richness and diversity attributes.
Species diversity refers to the pooled number and summed abundance of each species in all months, seasons, habitat types, and the entire study area. It was determined using the Shannon–Weaver [107] and Simpson’s index [108], whereas species richness was the number of species per unit area [109]. The statistical analysis was performed using the Vegan library in the R programming environment [110].
Community responses to landscape-scale habitat factors.
We used non-metric multidimensional scaling (NMDS) to assess bird community patterns in relation to landscape-scale habitat variables [111]. The analysis of similarity (ANOSIM) was performed to establish the significance of species composition across different habitat types [111]. The Simper analysis was used to assess the contribution of each species to community assemblages [111]. Species abundance was used to perform an ordination of habitat types in species space using the Bray–Curtis similarity index. A generalized linear model (GLM), with Poisson distribution and log link function in R, was used to assess the response of bird abundance to habitat variables. Bird abundance was used as the objective variable, whereas elevation, habitat features, and the distance to the closest dumping sites were used as explanatory variables. Elevation data were collected using GPS (Garmin-Montana 650), and the distance to the nearest sampling site was calculated using the distance matrix tool in QGIS [112]. We constructed two models of total abundance: one that contained both Milvus migrans and M. m. lineatus, and another that omitted both.
Results
Species richness and diversity
In all, 3,434 individuals of 28 diurnal raptors belonging to two orders and three families were observed during sampling (S2 Appendix). Twenty four species belonged to the family Accipitridae, three to Falconidae and one to Pandionidae. The highest number of species was found in farmlands [23], followed by undisturbed forests [22], forest-farmland interfaces [20], and water bodies and buffer zones [19]. The habitats with fewer species included urban built-up areas, green belts, and urban avenue plantations (eight species each). A high mean abundance was found in urban built-up areas (34.68 ±21.44), followed by undisturbed forests (27.79 ±9.71), farmlands (18.49 ±4.91), forest farmland interfaces (14.45 ±6.18), water bodies (12.50 ±3.50), and green belts (11.48 ±7.59) (Table 1). M. m. lineatus had the highest relative abundance (RA = 36.28) followed by Neophron percnopterus (RA = 13.48) and Aquila nipalensis (RA = 10.75), whereas Clanga clanga and Aquila rapax had the lowest relative abundance and thus low ranking (S2 Appendix, Fig 2). Among the seasons, summers (41.03 ±16.51) recorded the highest mean abundance, followed by winters (32.37 ±11.17), monsoon (30.17 ±13.60), and post-monsoon (14.82 ±5.38) (Table 1). The diurnal raptor group as a whole exhibited a modest level of diversity (H′ = 3.50). Farmlands were the most diverse habitat type (H′ = 2.58), whereas urban areas were the least diverse (H′ = 1.14). Winters recorded the highest diversity and evenness (H′ = 2.42, J = 0.72), whereas monsoons had the least values (H′ = 2.01, J = 0.65) (Table 1). The species were more evenly dispersed in water bodies and buffer zones (J = 0.82) followed by farmlands (0.80) and undisturbed forests (0.70).
MML: Milvus migrans lineatus; NP: Neophron percnopterus; AN: Aquila nipalensis, MM: Milvus migrans, GF: Gyps fulvus; GH: Gyps himalayensis; EC: Elanus caeruleus; AB: Accipiter badius; FT: Falco tinnunculus; CA: Circus aeruginosus.
In terms of habitat usage, 15 birds (53%) of all observed species were specialists, whereas 13 were generalists. Twelve of the specialists were forest raptors (n = 576), whereas 3 were water-dependent (n = 51). Observations on the food type and foraging behavior identified two broad trophic guilds, namely predators (22 species, n = 998) and carrion feeders (6 species, n = 2,436). Eight species of forest specialists were predators, whereas the remaining (all vultures) were carrion feeders. Eleven among the generalists were predators, whereas the remaining two were carrion feeders (Table 2).
Species similarity and habitat exclusiveness
Milvus migrans, M. m. lineatus, Aquila nipalensis, A. badius, Hieraaetus pennatus, Falco peregrinus, and Neophron percnopterus were found in all habitat categories and were considered ubiquitous. Among the habitats, farmlands shared a maximum of 21 species with undisturbed forests, followed by forest farmland interfaces and water bodies, which shared 20 species. Similarly, undisturbed forests shared 20 species with forest farmlands interfaces, followed by water bodies and buffer zones (17 species). Winters shared 27 species with the post-monsoon season, which was followed by summers (26 species). Summer and post-monsoon shared the maximum (25 species). Bray–Curtis similarity linkages across habitat types showed the formation of four clusters, namely forest farmland interfaces-water bodies and farmlands-green belt parks that had comparable raptor assemblages. The third and fourth clusters included densely populated urban areas and undisturbed forests with distinct raptor associations (Fig 3A). Among the seasons, summer, winter, and monsoon had comparable raptor assemblages and were therefore grouped, whereas the post-monsoon assemblages remained distinct and formed a separate cluster (Fig 3B).
FR: Undisturbed forests; FF: Forest farmland interfaces; FL: Farmlands; UB: Urban built-up areas; GB: Green belt and urban avenue plantations; WB: water bodies and buffer zones; PM: Post monsoon; S: Summer; M: Monsoon; W: Winter.
Whittaker curves
Whittaker curves (Fig 4) showed the species diversity among habitat categories, with green belts and urban built-up areas ranking the highest in terms of raptor abundance, followed by undisturbed forests and forest farmland interfaces. Water bodies and farmlands received a low ranking. Undisturbed forests, water bodies, farmlands, and forest farmland interfaces with slanting curves exhibited a high degree of species richness and evenness, whereas urban built-up areas and green belts were less speciose.
Coloured lines represent rank abundance diversity curves for six habitat types.
Community responses to landscape-scale habitat factors
Raptor assemblages constructed using NMDS (Fig 5) showed a significant variation in species composition across habitats (ANOSIM, number of permutations = 999; global R = 0.63; p = 0.0001), with observed species dissimilarity of 63.26% (R2 = 0.17). The SIMPER-based average species dissimilarity between forested sites (undisturbed forest and forest-farmland interfaces) was 67.02%. It consisted of 11 species, which accounted for more than 90% of the overall species composition. Table 3 summarizes the contribution of representative species and the average dissimilarity for different habitat categories.
Non-metric multidimensional scaling (NMDS) plot depicting raptor community assemblages in six contrasting habitat types using Bray-Curtis similarity. Pair wise ANOSIM tests revealed significant variation (p < 0.05) in raptor compositions. The vectors that stretch up to the point denote species, whereas the six big dots indicate habitat categories.
Effect of habitat characteristics on bird species abundance
The avian species abundance responded differently to the contrasting habitats when tested using the GLM (Table 4). In model one, which included the urban commensals M. migrans and M. m. lineatus, the abundance of all raptors was governed by elevation and distance to the nearest dumping sites. Except for water bodies and buffer zones, the abundance of species in all other habitat types differed significantly from farmlands. The gregarious assemblages of M. migrans and M. m. lineatus drive a high bird abundance in urban built-up areas. In the second model that excluded the commensals, the abundance of bird species was more strongly linked to elevation. The abundance decreased and remained low for forest farmland interfaces and urban built-up areas. Greenbelts and urban avenue plantations were expected to have the lowest abundance, implying their unsuitability for non-commensal raptors. In contrast, undisturbed forests and water bodies were predicted to behave better than greenbelts and urban avenue plantations. Non-commensal raptors preferred the forest-farmland interface and urban built-up regions.
Two models, one that included the commensals M. migrans and M. m. lineatus and second, excluding them, were run to analyze effect of habitat variables on raptor abundance.
Conservation status
Nine species, Aquila nipalensis, A. heliaca, A. rapax, Circus cyaneus, Buteo rufinus, B. buteo, Clanga clanga, Aegypius monachus and Pandion haliaetus were winter visitors. Falco subbuteo was found to be summer visitor whereas the remaining 18 were residents. Nine species were recognized as globally threatened (IUCN, 2020), which included Gyps bengalensis (critically endangered), Neophron percnopterus and Aquila nipalensis (endangered), Clanga hastata, C. clanga, Aquila heliaca and A. rapax (vulnerable), Gyps himalayensis and Aquila monachus (near threatened). The least concern group included 19 species (S2 Appendix).
Discussion
Twenty-eight species, reported during the present study accounted for 38% of all diurnal raptors in India [87] and 62% of those in the erstwhile state of Jammu and Kashmir [88]. Statistical analysis revealed that different habitat types differed in terms of species richness and abundance. Undisturbed forest patches, rocky cliffs and ridges, vast fallows and agricultural fields, water bodies (rivers, streams, and ponds), floodplains, and urban habitats infused with green spaces provide a favorable space for nesting, breeding, perching, and roosting, thereby resulting in a high raptor richness and abundance [17, 113–116]. Significant variation in species richness and abundance among habitat types was probably related to the morphology, hunting tactics, nesting, and foraging requirements [117], habitat condition, migratory behavior, and breeding season of the species [118, 119], in addition to human disturbances [120]. Landscape attributes determine avian richness and abundance [121, 122], which is high in mosaic lands [123–125] and limited by suitable breeding habitat and specific nest-site requirements [17, 84].
GLM results suggested that the abundance of raptors was regulated by elevation, habitat use, and distance to the dumping sites. Differential habitat usage, large home range [126], and elevational gradient could be the key drivers contributing to high raptor abundance. The higher elevations occupied by sub-tropical broad-leaved forests interspersed with Chirpine, with little human disturbance could be another reason for high raptor diversity. In addition, this high number could be linked to a stable and abundant prey base, low competition, and adequate nesting provisions [127]. Milvus migrans and M. m. lineatus, the most abundant urban commensals, accounted for more than 40% of the total observed raptor population. These generalists use man-made structures (building, bridges, towers, poles), urban green spaces, and stormwater drains as shelter, nesting sites, and food sources (including offal and anthropogenic refuse), achieving the largest numbers in urban localities [128]. Raptors are drawn to urban environments by perching locations near roadways (power lines and telephone poles) and road kills [129]. Numerous studies have demonstrated that urbanization impacts the diversity, composition, and abundance of bird communities [130–132], confirming the increased abundance of urban commensals in the study area. Because urbanization leads to biological homogeneity, urban-adapted species have become more common and locally abundant [133]. Medium-sized raptors successfully inhabit these habitats [134, 135] by locating ideal food, breeding, and roosting locations [136]. However, urbanization exerts a detrimental effect on vulnerable species [137, 138]. Eagles, hawks, and falcons [139] with unique habitat requirements [128] are more abundant in less disturbed and natural habitats [1, 128, 140] that provide a safe refuge, hostile environment, and prey species [126]. It consists of forest specialists, migrants, and nesting birds that are particularly sensitive to human presence.
The richness and diversity attributes increased with increased habitat heterogeneity. Agricultural areas and wide-open spaces serve as nesting and foraging sites for a variety of open space foragers, including buzzards and harriers [12, 141–144]. Apart from creating new habitats, irrigated crops increase the availability of food for birds of prey in the form of small mammals, voles, and rodents, which are ideal prey for western marsh harriers [145, 146], black kites [147, 148], black-winged kites, and migrant raptors such as booted eagle and steppe eagle [31, 149, 150]. Our study demonstrates the critical nature of forests and farmlands, which are home to over 90% of all raptor species recorded in the study area. Forests, as raptor habitats, are more vulnerable and hence demand conservation and effective protection [15, 151, 152]. Seven species, mostly residents, were identified across all landscape types being resilient to or having acclimated to landscape changes throughout time [12].
Given that food availability is a significant determinant of raptor density [17], the distance from dumping sites reduces human-subsidized food availability, thereby negatively affecting the raptor population. This supports the GLM results reported in the current study. Apart from birds and mammals [126], reptiles, amphibians, fish, and arthropods are the primary dietary sources for raptors [153]. Twenty-two species were recognized as predators and 6 as carrion feeders based on foraging data. M. migrans, M. m. lineatus, and N. percnopterus were the top most prevalent species along urban roadways, water bodies, and perches and found either foraging or roosting.
Others, such as G. fulvus, G. himalayensis, G. bengalensis, and A. monachus, were found in the undisturbed forests and/or forest-farmland interfaces, where they fed on dead wildlife and livestock. Carrion from large animals, deer, and hares in the forest may provide a rich food source for raptors [126, 154]. Unlike scavenging raptors, predatory raptors visually search for and hunt their prey [155]. The observed richness of predatory raptors was significantly higher than that of scavengers, which could be explained by the abundance of different food types in the study area’s mosaic ecosystems. Food availability [156] is the most important criterion for selecting suitable stopover sites for wintering [157]. Predatory winter migrants, including resident raptors, were frequently spotted feeding on lizards, rodents, insects, and birds in mosaic environments. Raptor size and diet appeared to be the most promising characteristics defining birds’ extensive patterns [54].
Although raptor species occupied a variety of habitats [158], no seasonal variation in raptor abundance was detected. However, despite the absence of a seasonal pattern, monthly changes in species richness and abundance were observed [159]. Ten species were migrants, including 9 winter visitors and 1 summer visitor, compared to 18 resident species. Seasonal migration patterns, local and regional habitat changes, large-scale population fluctuations, and climatic conditions may contribute to this migratory behavior [160–162]. During the study period, most of the winter migrants were reported from paddy fields and other farmlands located near wetlands or open areas close to streams and floodplains. During winters, only a few were observed in the undisturbed forests. Migrating species frequently use paddy fields as foraging habitats throughout the winter due to the presence of snakes, rodents, and crustaceans [163, 164]. In addition, the forest serves as a refuge for migratory species as a place to rest and feed until more favorable conditions return [165, 166]. Interestingly, five of the nine globally threatened raptors [106] were migrants, rendering them more vulnerable to threats [52, 167, 168], including the migration-related mortality [169]. The presence of globally threatened species, with a predominance of migratory raptors in the study area, substantiates its designation as a region’s top raptor conservation priority area.
Dissimilarity in community composition is one of the conspicuous features of community ecology [170, 171]. Comparing the compositions of different habitat types revealed the key mechanisms and habitat-specific impacts that shaped biodiversity composition and structure [172], which is critical for analyzing species invasions, changes induced by habitat fragmentation, and the effects of climate change. The average dissimilarity in species composition between habitat types was 63.26%, which could be attributed to the heterogeneous nature of habitats containing several ecosystems and exhibiting a range of environmental traits that contribute to community composition and variety.
Conclusions
Our study emphasizes the critical role of urban, forested, agricultural, and aquatic environments in the monitoring and conservation of raptors. A combination of natural, semi-natural, and urban environments serves as hotspots of landscape diversity, allowing the coexistence of a diverse range of species with varying habitat requirements. Numerous migratory species, including a few globally threatened birds, reflect the habitat’s uniqueness and potentiality. Effective strategies are required to improve, protect, and conserve these ecosystems to sustain biological integrity, avoid species extinction, and accelerate species recovery. We believe this study has significant implications for future efforts to conserve raptors, particularly in this region of the northwestern Himalayas.
Supporting information
S1 Appendix. Spatial attributes of sample locations, including geomorphological features, sampling plots, and the degree of disturbance.
https://doi.org/10.1371/journal.pone.0246555.s001
(DOCX)
S2 Appendix. List of diurnal raptors recorded in the study area, their abundance, guilds and conservation status.
https://doi.org/10.1371/journal.pone.0246555.s002
(DOCX)
Acknowledgments
The authors would like to express their gratitude to the Rector, Bhaderwah Campus, University of Jammu, for giving the required permits for this work. Department of Wildlife Protection, Government of the UT of Jammu and Kashmir, is to be commended for technical and logistical support provided during the surveys. The authors gratefully acknowledge Ashwin Vishwanathan for helping with the statistical analysis and Dinesh, Anil and Ajaz for assisting with field surveys.
References
- 1. Carrete M, Tella J. Individual consistency in flight initiation distances in burrowing owls: a new hypothesis on disturbance-induced habitat selection. Biol. Lett. 2010; 6:167–170. pmid:19864278
- 2. Margules CR, Pressey RL. Systematic conservation planning. Nature. 2000; 405:243–253. pmid:10821285
- 3.
Chambers SA. Birds as environmental indicators: review of literature. Parks Victoria Technical Series No. 55. Parks Victoria, Melbourne; 2008.
- 4. Sergio F, Caro T, Brown D, Clucas B, Hunter J, Ketchum J, et al. Top predators as conservation tools: ecological rationale, assumptions, and eFFcacy. Annu. Rev. Ecol. Evol. Syst. 2008; 39:1–19.
- 5. Jiménez B, Merino R, Abad E, Rivera J, Olie K. Evaluation of organochlorine compounds (PCDDs, PCDFs, PCBs and DDTs) in two raptor species inhabiting a mediterranean island in Spain. Env. Sci. Pollut. Res. 2007;1:61–68.
- 6. Donázar JA, Cortés-Avizanda A, Fargallo JA, Margalida A, Moleón M, Morales-Reyes Z, et al. Roles of raptors in a changing world: from flagships to providers of key ecosystem services. Ardeola. 2016; 63:181–234. https://doi.org/10.13157/arla.63.1.2016.rp8
- 7. Thiollay JM. The decline of raptors in West Africa: long-term assessment, human pressure and role of protected areas. Ibis. 2006; 48:240–254. https://doi.org/10.1111/j.1474–919X.2006.00531.x
- 8. Piana R, Marsden SJ. Diversity, community structure and niche characteristics within a diurnal raptor assemblage of northwestern Peru. Condor. 2012; 114:279–289.
- 9. Sergio F, Newton I, Marchesi L. Conservation: Top predators and biodiversity. Nature. 2005; 436(7048): 192. pmid:16015318
- 10. Bogliani G, Sergio F, Tavecchia G. Woodpigeons nesting in association with hobby falcons: advantages and choice rules. Anim. Behav. 1999; 57:125–131. pmid:10053079
- 11. Sergio F, Marchesi L, Pedrini P, Penteriani V. Coexistence of a generalist owl with its intra guild predator: distance-sensitive or habitat-mediated avoidance? Anim. Behav. 2007; 74:1607–1616.
- 12. Tinajero R, Barragán F, Chapa-Vargas L. Raptor functional diversity in scrubland-agricultural landscapes of northern-central-mexican dry land environments. Trop. Conserv. Sci. 2017; 10:1–18. https://doi.org/10.1177/1940082917712426
- 13.
Goriup P, Tucker G. Assessment of the merits of a CMS instrument covering migratory raptors in Africa and Eurasia. London: Department for environment, food and rural affairs, wildlife species conservation division; 2007. pmid:17310885
- 14. Virani M, Watson RT. Raptors in the East African tropics and Western Indian Ocean islands: state of ecological knowledge and conservation status. J. Raptor Res. 1998; 32:28–39.
- 15. McClure CJW, Martinson L, Allison TD. Automated monitoring for birds in flight: proof of concept with eagles at a wind power facility. Biol. Conserv. 2018; 224: 26–33.
- 16. Bierregaard RO. Conservation status of birds of prey in the South American tropics. J. Raptor Res. 1998; 32:19–27.
- 17. Newton I. Population ecology of raptors. South Dakota: Buteo Books; 1979.
- 18. Real J, Mañosa S. Demography and conservation of western European Bonelli’s eagle Hieraaetus fasciatus populations. Biol. Conserv. 1997; 79:59–66.
- 19. Hall JC, Chhangani AK, Warner TA. Spatial characteristics of nest sites of critically endangered Indian vultures (Gyps indicus) in Rajasthan, India. Indian For. 2015; 141:1–5.
- 20. Owens IFR, Bennett PM. Ecological basis of extinction risk in birds: Habitat loss versus human persecution and introduced predators. Proc. Natl. Acad. Sci. 2000; 97:12144–12148. pmid:11005835
- 21. Watson RT. Conservation and ecology of raptors in the tropics. J. Raptor. Res. 1998; 32: 1 – 2.
- 22. Bennett PM, Owens IFR. Variation in extinction risk among birds: chance or evolutionary predisposition? Proc. R. Soc. B Biol. Sci. 1997; 264:401–408. https://doi.org/10.1098/rspb.1997.0057
- 23. Anderson D. Landscape heterogeneity and diurnal raptor diversity in Honduras: the role of indigenous shifting cultivation. Biotropica 2001; 33:511–519. https://doi.org/10.1111/j.1744-7429.2001.tb00205.x
- 24. Panasci TA, Whitacre DF. Roadside Hawk breeding ecology in forest and farming landscapes. Wilson Bull. 2002; 114(1):114–121.
- 25.
White CM. Current problems and techniques in raptor management and conservation. Transactions of the thirty-ninth North American Wildlife Conference. Washington: Wildlife Management Institute; 1974. p. 301–312.
- 26.
Guisan A, Thuiller W, Zimmermann NE. Habitat suitability and distribution models: With applications in R. Cambridge: Cambridge University Press; 2017.
- 27.
Morrison ML, Marcot BG, Mannan RW. Wildlife-habitat relationships: Concepts and applications. 3rd ed. Washington, DC: Island Press; 2006.
- 28.
Whitacre DF. (2012) Neotropical birds of prey: biology and ecology of a forest raptor community. Ithaca: Comstock Publishing Associates.
- 29. Jankowiak L, Antczak M, Kwieciñski Z, Szymañski P, Tobolka M, Tryjanowski P. Diurnal raptor community wintering in an extensively used farmland. Ornis Fenn. 2015a; 92: 76–86.
- 30. Sarà M, Mascara R, Lopez-Lopez P. Understanding the coexistence of competing raptors by Markov chain analysis enhances conservation of vulnerable species. J. Zool. 2016; 299:163–71.
- 31. Herremans M, Herremans-Tonnoeyr D. Land use and the conservation status of raptors in Botswana. Biol. Conserv. 2000; 94:31–41. https://doi.org/10.1016/S0006-3207(99)00166–4
- 32.
Greene HW. Species richness in tropical predators. In: Almeda F, Pringle C, editors. Tropical rainforests: diversity and conservation. San Francisco: California Academy of Science; 1988. p. 259–274.
- 33. Terborgh J. Maintenance of diversity in tropical forests. Biotropica. 1992; 24:283–292.
- 34. Simberloff D. Flagships umbrellas and keystones: is single-species management pass´e in the landscape era? Biol. Conserv. 1998; 83:247–257.
- 35.
Manly BFJ, McDonald LL, Thomas DL, McDonald TL, Erickson WP. Resource Selection by Animals: Statistical Analysis and Design for Field Studies, 2nd ed. Boston, MA: Kluwer Academic Publishers; 2002.
- 36. Witmer GW. Wildlife population monitoring: some practical considerations. Wildl. Res. 2005; 32:259–263.
- 37. Sanchez-Zapata JA, Carrete M, Gravilov A, Sklyarenko S, Ceballos O, Donazar JA, et al. Land use changes and raptor conservation in steppe habitats of Eastern Kazakhastan. Biol Conserv. 2003;111:71–7.
- 38. Wu Y, Fujita G, Higuchi H. What landscape elements are correlated with the distribution of wintering Grey-faced Buzzards Butastur indicus in the Sakishima Islands, southwestern Japan? Ornithol. Sci. 2006; 5: 157–163.
- 39. Basnet TB, Rokaya MB, Bhattarai BP, Münzbergová Z. Heterogeneous landscapes on steep slopes at low altitudes as hotspots of bird diversity in a hilly region of Nepal in the Central Himalayas. PLoS ONE 2016;11(3): e0150498. pmid:26938616
- 40. Voskamp A, Baker DJ, Stephens PA, Valdes PJ, Willis SG. Global patterns in the divergence between phylogenetic diversity and species richness in terrestrial birds. J Biogeogr. 2017; 44:709–21.
- 41. Price TD, Hooper DM, Buchanan CD, Johansson US, Tietze DT, Alström P, et al. Niche filling slows the diversification of Himalayan songbirds. Nature. 2014; 509: 222–5. pmid:24776798
- 42. Pandey N, Khanal L, Chalise MK. Correlates of avifaunal diversity along the elevational gradient of Mardi Himal in Annapurna Conservation Area, Central Nepal. Avian Res. 2020; 11:31.
- 43. Gavashelishvili A, McGrady MJ. Breeding site selection by bearded vulture (Gypaetus barbatus) and Eurasian grifon (Gyps fulvus) in the Caucasus. Anim Conserv. 2006; 9:159–70.
- 44.
Hansson A, Åkesson S. Animal movement across scales.1st ed. Oxford: Oxford University Press;2014.
- 45. Carnicer J, Brotons L, Stefanescu C, Peñuelas J. Biogeography of species richness gradients: linking adaptive traits, demography and diversification. Biol. Rev. 2011; 87:457–79. pmid:22129434
- 46. McClure CJW, Westrip JRS, Johnson JA, Schulwitz SE, Virani MZ, Davies R, et al. State of the world’s raptors: Distributions threats and conservation recommendations. Biol. Conserv. 2018; 227:390–402.
- 47. Dirzo R, Raven PH. Global state of biodiversity and loss. Annu. Rev. Environ. Resour. 2003; 28:137–167.
- 48. Ceballos G, Ehrlich PR, Dirzo R. Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines. Proc. Natl. Acad. Sci. 2017; 114:201704949. pmid:28696295
- 49.
Thiollay JM. Falconiformes of Tropical Rainforests: A Review. ICBP Tech Publishing; 1985. p. 155–165. https://doi.org/10.1007/BF00378906 pmid:28310436
- 50. Thiollay JM. Current status and conservation of Falconiformes in tropical Asia. J. Raptor Res. 1998; 32:40–55.
- 51. Thiollay JM, Rahman Z. The raptor community of central Sulawesi: habitat selection and conservation status. Conserv. Biol. 2002; 3:128–137.
- 52.
Bildstein KL. Migrating Raptors of the World: Their Ecology and Conservation. New York: Cornell University Press; 2006.
- 53. Fahrig L. Effects of habitat fragmentation on biodiversity. Annu. Rev. Ecol. Evol. Syst. 2003;34(1): 487–515
- 54. Sekercioglu C. Bird functional diversity and ecosystem services in tropical forests, agroforests and agricultural areas. J Ornithol. 2012; 153:153–161. https://doi.org/10.1007/s10336-012-0869-4
- 55. Whitfield DP, David RA, McLeod DRA, Watson J, Fielding AH, Haworth FR. The association of grouse moor in Scotland with the illegal use of poisons to control predators. Biol. Conserv. 2003; 114(2):157–163.
- 56. Brochet AL, Vav Den Bossche W, Jones VR, Arnardottir H, Damoc D, Demko M, et al. Illegal killing and taking of birds in Europe outside the Mediterranean: assessing the scope and scale of a complex issue. Bird Conserv. Int. 2017; 26:1–31.
- 57. Oaks JL, Gilbert M, Virani MZ, Watson RT, Meteyer CU, Rideout B, et al. Diclofenac residues as the cause of vulture population decline in Pakistan. Nature. 2004a; 427: 630–633. pmid:14745453
- 58. Murn C, Khan U, Farid F. Vulture populations in Pakistan and the Gyps vulture restoration project. Vulture News. 2008; 58:35–43.
- 59. Ogada D, Shaw P, Beyers RL, Buij R, Murn C, Thiollay JM, et al. Another continental vulture crisis: Africa’s vultures collapsing toward extinction. Conserv. Lett. 2016; 9:89–97.
- 60. Garbett R, Maude G, Hancock P, Kenny D, Reading R, Amar A. Association between hunting and elevated blood lead levels in the critically endangered African white-backed vulture Gyps Africanus. Sci. Total Environ. 2018b; 630:1654–1665. pmid:29550066
- 61. Vogler BR, Hoop R, Sinniger M, Albini S. Intentional methomyl-poisoning of peregrine falcons (Falco peregrinus) in Switzerland. Eur. J. Wildl. Res. 2015; 61(4):611–615.
- 62. Botha A. 65 endangered vultures killed in poisoning incident. African Geographic. Available online on http://africageographic.com/blog/65-endangered-vultures-killed-in-poisoning-incident; 2015.
- 63. Galligan TH, Amano T, Prakash VM, Kulkarni M, Shringarpure R, Prakash N, et al. Have population declines in Egyptian vulture and red-headed vulture in India slowed since the 2006 ban on veterinary diclofenac? Bird Conserv. Int. 2014; 24:272–281.
- 64. Lehman RN. Raptor electrocution on power lines: current issues and outlook. Wildl. Soc. Bull. 2001; 29:804–813.
- 65. Kagan RA. Electrocution of raptors on power lines: a review of necropsy methods and findings. Vet Pathol. 2016; 53(5):1030–1036. pmid:27154543
- 66. Angelov I, Hashim I, Oppel S. Persistent electrocution mortality of Egyptian vultures Neophron percnopterus over 28 years in East Africa. Bird Conserv. Int. 2013; 23:1–6. https://doi.org/10.1017/S0959270912000123
- 67. Mojica EK, Dwyer JF, Harness RE, Williams GE, Woodbridge B. Review and synthesis of research investigating golden eagle electrocutions. J. Wildl. Manag. 2018; 82:495–506.
- 68. Maceda JJ, Sarasola JH, Emilio M, Pessino M. Presas consumidas por el Águila Coronada (Harpyhaliaetus coronatus) en el límite sur de su rango de distribución en Argentina. Ornitol. Neotrop. 2003; 14:419–422.
- 69. Cusa M, Jackson DA, Mesure M. Window collisions by migratory bird species: urban geographical patterns and habitat associations. Urban Ecosys. 2015; 18:1427–1446. https://doi.org/10.1007/s11252-015-0459-3
- 70. Klippel AH, Oliveira PV, Britto KB, Freire BF, Moreno MR, Dos Santos AR, Banhos A, Paneto GG. Using DNA barcodes to identify road-killed animals in two Atlantic forest nature reserves Brazil. PLoS One. 2015; 10:1–15. pmid:26244644
- 71. Symes CT. Amur falcon Falco amurensis slaughter in Nagaland India. Gabar. 2012; 23: 69–73.
- 72. Dalvi S, Haralu B. Doyang reservoir: a potential IBA in Nagaland. Mistnet. 2014; 15:24–28.
- 73. Markandya A, Taylor T, Longo A. Counting the cost of vulture declines–economic appraisal of the benefits of the Gyps vulture in India. Ecol. Econ. 2008;67:194–204.
- 74.
Watson J. The golden eagle. London; 2010.
- 75. Monadjem A, Virani MZ, Jackson C, Reside A. Rapid decline and shift in the future distribution predicted for the endangered Sokoke Scops Owl Otus ireneae due to climate change. Bird Conserv. Int. 2013; 23:247–258.
- 76. Martin RO, Sebele L, Koeslag A, Curtis O, Abadi F, Amar A. Phenological shifts assist colonisation of a novel environment in a range-expanding raptor. Oikos. 2014b; 123:1457–1468.
- 77. Garcia-Heras M-S, Arroyo B, Mougeot F, Amar A, Simmons RE. Does timing of breeding matter less where the grass is greener? Seasonal declines in breeding performance differ between regions in an endangered endemic raptor. Nat. Conserv. 2016; 15:23–45.
- 78.
Franke A. Priorities for Gyrfalcon research: food weather and phenology in a changing climate. In: Anderson DL, McClure CJW, Franke A, editors. Applied Raptor Ecology: Essentials from Gyrfalcon Research. USA: The Peregrine Fund Boise Idaho; 2017. p. 11–33.
- 79. Iknayan KJ, Beissinger SR. Collapse of a desert bird community over the past century driven by climate change. Proc. Natl. Acad. Sci. 2018; 201805123. pmid:30082401
- 80. Laurance WF, Sayer J, Cassman KG. Agricultural expansion and its impacts on tropical nature. Trends Ecol. Evol. 2014;29:107–116. pmid:24388286
- 81.
Grande JM, Orozco-Valor PM, Liébana MS, Sarasola JH. Birds of prey in agricultural landscapes: the role of agriculture expansion and intensification. In: Sarasola JH, Grande JM, Negro JJ, editors. Birds of Prey: Biology and Conservation in the XXI Century. New York: Springer publication, 2018. p. 197–228.
- 82.
Tucker GM, Heath MF. Birds in Europe: their conservation status. UK: Birdlife International Cambridge; 1994.
- 83.
BirdLife International. Birds in the European Union: a status assessment. Netherlands: BirdLife International; 2004.
- 84.
Ferguson-Lees J, Christie DA. Raptors of the World. London: Christopher Helm; 2001. p. 320.
- 85.
Cramp S. The complete birds of the Western Palearctic. Oxford University Press; 1998.
- 86.
Mebs T, Schmidt D. Die Greifvögel Europas Nordafrikas und Vorderasiens Biologie Kennzeichen Bestände. Franckh-Kosmos Verlags Stuttgart 495; 2006.
- 87.
BirdLife International. IUCN red list for birds. Downloaded from http://www.birdlife.org on 20/12/2020; 2017.
- 88. Suhail I, Ahmad R, Ahmad K. Avifaunal diversity in Jammu and Kashmir State. In: Dar GH, Khuroo AA, editors. Biodiversity of the Himalaya: Jammu and Kashmir state: Topics in Biodiversity and Conservation; 2020. p. 897–931. https://doi.org/10.1007/978-981-32-9174-4_35
- 89. Kichloo MA, Kumar S, Sharma N. Breeding site records of three sympatric vultures in a mountainous cliff in Kahara-Thathri Jammu & Kashmir India. J. Threat. Taxa. 2020; 12(09):16166–16169. https://doi.org/10.11609/jott.5537.12.9.16166-16169
- 90. Sharma N, Rana SK, Raina P, Amir R, Kichloo MA. An annotated checklist of the birds of upper Chenab catchment Jammu and Kashmir India. J. Threat. Taxa 2018; 10:11869–11894.
- 91. Sohil A, Sharma N. Bird diversity and distribution in mosaic landscapes around Jammu, Jammu & Kashmir. Acta. Eco.l Sin. 2020; 40(4):323–338.
- 92. Sohil A. and Sharma N. (2020) Assessing the bird guild patterns in heterogeneous land use types around Jammu, Jammu and Kashmir, India. Ecological Processes, 9(49):1–15. https://doi.org/10.1186/s13717-020-00250-9
- 93.
eBird. Electronic data base. https://ebird.org/region/IN-JK?yr=all. Accessed June 1,2021
- 94.
Fuller MR, Mosher JA. Raptor survey techniques. Washington, DC: US Fish and Wildlife Service; 1987. p. 37–65.
- 95. Millsap BA, LeFranc MN Jr. Road transect counts for raptors: how reliable are they? J. Raptor Res. 1988;22:8–16
- 96.
Whitacre DF, Turley CW. Further comparisons of tropical raptors census techniques. In: Edited by: Burnham WA, Whitacre DF, Jenny JP, editors. Maya Project: use of raptors and other fauna as environmental indicators for design, management, and monitoring of protected areas and for building local capacity for conservation in Latin America. Boise: Progress report III. The Peregrine Fund; 1990:71–92.
- 97. Austin JE, Sklebar HT, Gutensperger GR, Buhl TK. Effects of roadside transect width on waterfowl and wetland estimates. Wetlands 2000; 20: 660–670. https://doi.org/10.1672/02775212(2000)020[0660:EORTWO]2.0.CO;2
- 98.
Bibby CJ, Burgess ND, Hill DA. Bird Census Techniques. London: Academic Press; 1992.
- 99.
Andersen DE. Survey techniques. In: Bird DM, Bildstein KL, Blaine WA, editors. Raptor research and management techniques. Hancock House Publisher; 2007:89–100.
- 100. Vergara P. Time-of-day bias in diurnal raptor abundance and richness estimated by road surveys. Rev. Catalana d’Ornitol. 2010; 26: 22–30.
- 101.
Grimmett R, Inskipp C, Inskipp T. Birds of the Indian Subcontinent: India Pakistan Sri Lanka Nepal Bhutan Bangladesh and the Maldives. Bloomsbury Publishing; 2013. p. 528.
- 102.
Naoroji R. Birds of Prey of the Indian subcontinent. New Delhi: Om Books International publishing; 2011. p. 692. https://doi.org/10.1136/medethics-2011-100187 pmid:22174329
- 103.
Grewal B, Sen S, Singh S, Devasar N, Bhatia G. A pictorial field guide to birds of India Pakistan Nepal Bhutan Sri Lanka and Bangladesh. New Delhi: Om Books International publishing; 2016.
- 104. De Graaf RM, Tilghman NG, Anderson SH. Foraging guilds of North American birds. Environ. Manag. 1985; 9:493–536.
- 105.
The Cornell Lab of Ornithology. All about birds: Raptors. https://www.allaboutbirds.org/news/search/?q=raptors. Accessed January 1,2021
- 106.
IUCN. The IUCN Red List of Threatened Species version 2021–1. https://www.iucnredlist.org. 2021; Accessed June 5,2021.
- 107.
Shannon CE, Weaver W. The Mathematical theory of communication. Urbana: University of Illinois Press; 1949.
- 108. Simpson EH. Measurement of Diversity. Nature. 1949; 163:688.
- 109. Whittaker RH. Evolution and measurement of species diversity. Taxon. 1972; 21:213–51.
- 110.
R Core Team. R: A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing; 2020. https://www.R-project.org/
- 111. Clarke KR, Warwick RM. A further biodiversity index applicable to species lists: variation in taxonomic distinctness. Mar. Ecol. Proc. Ser. 2001; 84: 21–29.
- 112.
QGIS Development Team. QGIS Geographic Information System. Open Source Geospatial Foundation Project. 2020. http://qgis.osgeo.org
- 113.
Pendleton BA, Millsap BA, Cline KW. Habitat management. In: Pendleton BA, Millsap BA, Cline KW, Bird DA, editors. Raptor management techniques manual. Science Technical Series No. 10. Washington: National Wildlife Federation; 1987. p. 215–237.
- 114.
Craighead JJ, Craighead FC. Hawks owls and wildlife. New York: Stackpole Company and Wildlife Management Institute; 1956. https://doi.org/10.1016/0002-9610(56)90132-5 pmid:13353805
- 115.
Janes SW. Habitat selection in raptorial birds. In: Cody M, editor. Habitat selection in birds. New York: Academic Press; 1985. p. 159–188.
- 116.
Tapia L, Zuberogoitia I. Breeding and nesting biology in Raptors. In: Sarasola JH, Grande JM, Negro JJ, editors. Birds of Prey. Switzerland: Springer Publishing; 2018. p. 63–94. https://doi.org/10.1007/978-3-319-73745-4
- 117. Solonen T. Spacing of birds of prey in southern Finland. Ornis Fenn. 1993; 70: 129–143.
- 118. Mengesha G, Bekele A. Diversity and relative abundance of birds of Alatish National Park. Int. J. Environ. Sci. 2008; 34(2):15–22.
- 119. Tilahun C, Travi Y, Valles V. Mechanism of degradation of the quality of natural water in the Lakes region of the Ethiopian Rift Valley. Water Resour. 2001; 35:2819–2832.
- 120. Zhang Y, Fox AD, Cao L, Jia Q, Lu C, Prins HHT, De-Boer WF. Effects of ecological and anthropogenic factors on waterbird abundance at a Ramsar Site in the Yangtze River Floodplain. Ambio. 2019; 48(3):293–303. pmid:29987519
- 121. Miller JN, Brooks RP, Croonquist MJ. Effects of landscape patterns on biotic communities. Landscape Ecol. 1997; 12:137–153.
- 122. Pino J, Rodà F, Ribas J, Pons X. Landscape structure and bird species richness: implications for conservation in rural areas between natural parks. Landsc. Urban Plan. 2000; 49:35–48.
- 123. Katayama N, Osawa T, Amano T, Kusumoto Y. Are both agricultural intensification and farmland abandonment threats to biodiversity? A test with bird communities in paddy-dominated landscapes. Agric. Ecosyst. Environ. 2014; 214:21–30.
- 124. Hamada A, Fukui W, Mizushima M. The study of the relationship between connectivity of rural land use and urban fringe area Kyoto city. J Jap. Soc. Reveget. Tech. 2015; 41: 145–150.
- 125. Norfolk O, Jung M, Platts PJ, Malaki P, Odeny D, Marchant R. Birds in the matrix: the role of agriculture in avian conservation in the Taita Hills Kenya. Afr. J. Ecol. 2017; 55: 530–540.
- 126.
Petty SJ. Ecology and Conservation of Raptors in Forests. London: Forestry Commission Bulletin 118; 1998.
- 127.
Cooke R, Hogan F, Isaac B, Weaving M, White JG. Urbanization and Raptors: Trends and Research Approaches. In: Boal CW, Dykstra CR, editors. Urban Raptors. Washington: Island Press; 2018.
- 128.
Solaro C. Costs and benefits of urban living in raptors. In: Sarasola JH, Grande JM, Negro JJ, editors. Birds of Prey. Springer publishing; 2018. p. 177–196. https://doi.org/10.1007/978-3-319-73745-4
- 129. Meunier FD, Verheyden C, Jouventin P. Use of roadsides by diurnal raptors in agricultural landscapes. Biol. Conserv. 2000; 92:291–298.
- 130. Blair RB. Land use and avian species diversity along an urban gradient. Ecol Appl.1996; 6:506–519.
- 131. Clergeau P, Savard JPL, Mennechez G, Falardeau G. Bird abundance and diversity along an urban-rural gradient: a comparative study between two cities on different continents. Condor 1998;100:413–425.
- 132. Ortega-Álvarez R, MacGregor-Fors I. Living in the big city: effects of urban land-use on bird community structure, diversity, and composition. Lands Urban Plan. 2009; 90: 189–195.
- 133.
Pennington DN, Blair RB. Using gradient analysis to uncover pattern and process in urban bird communities. In: Lepczyk CA, Warren PS, editors. Urban bird ecology and conservation: studies in avian biology. Berkeley: University of California Press; 2012. p. 9–32.
- 134. Stout WE, Rosenfield RN. Colonization, growth, and density of a pioneer Cooper’s Hawk population in a large metropolitan environment. J. Raptor Res. 2010; 44:255–267.
- 135. Altwegg R, Jenkins A, Abadi F. Nest boxes and immigration drive the growth of an urban Peregrine Falcon Falco peregrinus population. Ibis. 2014; 156:107–115. https://doi.org/10.1111/ibi.12125
- 136. Mörtberg UM. Resident bird species in urban forest remnants; landscape and habitat perspectives. Lands. Ecol. 2001; 16(3):193–203. https://doi.org/10.1023/A:1011190902041
- 137. Savard JPL, Clergeau P, Mennechez G. Biodiversity concepts and urban ecosystems. Lands Urban Plan. 2000; 48(3): 131–142. https://doi.org/10.1016/S0169-2046(00)00037-2
- 138. Hager SB. Human-related threats to urban raptors. J. Raptor Res. 2009; 43(3): 210–226. https://doi.org/10.3356/JRR-08-63.1
- 139. Berry M, Bock C, Haire S. Abundance of diurnal raptors on open space grasslands in an urbanized landscape. Condor. 1998; 100: 601–608. http://hairelab.com/files/Berryetal1998
- 140. Bellocq M, Filloy J, Garaffa P. Influence of agricultural intensity and urbanization on the abundance of the raptor Chimango caracara (Milvago chimango) in the Pampean region of Argentina. Ann. Zool. Fenn. 2008; 45:128–134.
- 141. Pedrini P, Sergio F. Golden eagle Aquila chrysaetos density and productivity in relation to land abandonment and forest expansion in the alps. Bird Study. 2001; 48:194–199.
- 142.
Watson RT, Cade TJ, Hunt G, Fuller M, Potapov E. Gyrfalcons and Ptarmigan in a Changing World. vol. I and II. The Peregrine Fund Boise; 2011.
- 143.
Thiollay JM. Family Accipitridae (hawks and eagles). In: del Hoyo J, Elliott A, Sargatal J, editors. Handbook of the birds of the world volume 2. New world vultures to guineafowl. Spain: Lynx Editions; 1994. p. 52–105.
- 144. Garcia JT, Alda F, Terraube J, Mougeot F, Sternalski A, Bretagnolle V, et al. Demographic history genetic structure and gene flow in a steppe-associated raptor species. BMC Evol. Biol. 2011; 11:333. pmid:22093489
- 145.
Molina B, Martínez F. El Aguilucho Lagunero en España. Población en 2006 y métodos de censo. Madrid: Seo/BirdLife; 2008.
- 146. Cardador L, Carrete M, Manosa S. Can intensive agricultural landscapes favour some raptor species? The marsh-harrier in North-Eastern Spain. Anim. Conserv. 2011; 14:382–390.
- 147. Mougeot F, Garcia JT, Viñuela J. Breeding biology behaviour diet and conservation of the red kite (Milvus milvus) with particular emphasis on Mediterranean populations. In: Zuberogoitia I, Martínez JE, editors. Ecology and conservation of European dwelling forest raptors and owls; 2011.p. 190–204.
- 148. Paz A, Jareño D, Arroyo L, Viñuela J, Arroyo B, Mougeot F, et al. Avian predators as a biological control system of common vole (Microtus arvalis) populations in North-Western Spain: experimental set-up and preliminary results. Pest Manag. Sci. 2013; 69:444–450. pmid:22517676
- 149. Virani MZ, Harper DM. Factors influencing the breeding performance of the Augur Buzzard Buteo augur in southern Lake Naivasha Rift Valley Kenya. Ostrich. 2009; 80:9–17.
- 150. Buij R, Croes BM, Gort G, Komdeur J. The role of breeding range diet mobility and body size in associations of raptor communities and land-use in a west African savanna. Biol. Conserv. 2013; 166:231–246.
- 151. Brooks TM, Mittermeier RA, Da Fonseca GAB, Gerlach J, Hoffmann M, Lamoreux JF, et al. Global biodiversity conservation priorities. Science. 2006; 313:58–61. pmid:16825561
- 152.
Sarasola JH, Grande JM, Bechard MJ. Conservation status of neotropical raptors. In: Sarasola JH, Grande JM, Negro JJ, editors. Birds of Prey: Biology and Conservation in the XXI Century. Switzerland: Springer Publishing; 2018. p. 373–394.
- 153. Gamauf A, Preleuthner M, Winkler H. Philippine birds of prey: Interrelations among habitat morphology and behavior: The Auk. 1998; 115(3):713–726.
- 154. Fisher IJ, Pain DJ, Thomas VG. A review of lead poisoning from ammunition sources in terrestrial birds. Biol. Conserv. 2006; 131(3):421–432.
- 155. Jones MP; Pierce KE; Ward D. Avian vision: a review of form and function with special consideration to birds of prey. J. Exotic. Pet. Med. 2007: 16:69–87.
- 156. Smith SB, McPherson KH, Backer JM, Pierce BJ, Podlesak DW, McWilliams SR. Fruit quality and consumption by songbirds during autumn migration. Wilson J. Ornithol. 2007; 119:419–428.
- 157. Sarasola JH, Negro JJ. Hunting success of wintering Swainson’s Hawks: environmental effects on timing and choice of foraging method. Can. J. Zool. 2005; 83:1353–1359.
- 158. Motta-Junior J; Granzinolli MAM; Monteiro AR. Miscellaneous ecological notes on Brazilian birds of prey and owl. Biota Neotrop. 2010; 10:255–259.
- 159. Martos-Martins R, Donatelli RJ. Community of diurnal birds of prey in an urban area in southeastern Brazil. Neotrop. Bio. and Cons. 2020;15(3):245–265. https://doi.org/10.3897/neotropical.15.e52251
- 160. Aynalem S, Bekele A. Species composition relative abundance and distribution of bird fauna of riverine and wetland habitats of Infranz and Yiganda at southern tip of Lake Tana Ethiopia. Trop. Ecol. 2008; 49:199–209.
- 161. Ericia V, Den B, Tom Y, Meire P. Water bird communities in the Lower Zeeschelde: Long-term changes near an expanding harbour. Hydrobiology. 2005; 540:237–258.
- 162. Gaston KJ, Blackburn TM, Greenwood JD, Greroryx RD, Rachel MQ, Lawton JH. Abundance-occupancy relationships. J. Appl. Ecol. 2000; 37:39–59.
- 163. Maeda T, Yoshida H. Responses of birds in rice fields to winter flooding. Jap. J. Ornithol. 2009; 58:55–64.
- 164. Katayama N, Amano T, Naoe S, Yamakita T, Komatsu I, Takagawa SI, et al. Landscape Heterogeneity biodiversity relationship: Effect of range size. PLoS ONE. 2014; 9(3):e93359. pmid:24675969
- 165.
Manu SA. Effects of habitat fragmentation on the distribution of forest birds in south western Nigeria with particular reference to the Ibadan Malimbe and other malimbes. Ph.D Thesis. University of Oxford; 2000.
- 166. Girma Z, Mamo Y, Mengesha G, Verma A, Asfaw T. Seasonal abundance and habitat use of bird species in and around Wondo Genet Forest south-central Ethiopia. Ecol. Evol. 2017; 7:3397–3405. pmid:28515875
- 167. Sanderson FJ, Donald PF, Pain DJ, Burfield IJ, van Bommel FPJ. Longterm population declines in Afro-Palearctic migrant birds. Biol. Conserv. 2006; 131:93–105.
- 168. Both C, Van Turnhout CA, Bijlsma RG, Siepel H, Van Strien AJ, Foppen RP. Avian population consequences of climate change are most severe for long distance migrants in seasonal habitats. Proc. R. Soc. Lond. B. Biol. Sci. 2009;1685: 1259–1266. pmid:20018784
- 169. Klaassen RH, Hake M, Strandberg R, Koks BJ, Trierweiler C, Exo KM, et al. When and where does mortality occur in migratory birds? Direct evidence from long-term satellite tracking of raptors. J. Anim. Ecol. 2014;83: 176–184. pmid:24102110
- 170. Chao A, Chazdon RL, Colwell RK, Shen TJ. A new statistical approach for assessing similarity of species composition with incidence and abundance data. Ecol. Lett. 2005; 8(2): 148–159.
- 171. Legendre P, Cáceres MD. Beta diversity as the variance of community data: dissimilarity coefficients and partitioning. Ecol. Lett. 2013; 16(8): 951–963. pmid:23809147
- 172. Socolar JB, Gilroy JJ, Kunin WE, Edwards DP. How should beta-diversity inform biodiversity conservation? Trend. Ecol. Evol. 2016;31(1): 67–80. pmid:26701706