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Woolly-Necked Stork (Ciconia episcopus) Activity Budget in Lowland Nepal's Farmlands: The Influence of Wetlands, Seasonal Crops, and Human Proximity
Abstract
Tropical farmlands experience dramatic seasonal variations in landscape conditions and have continuous human presence, providing potentially challenging settings for resident waterbirds. Behavior of the globally threatened Woolly-necked Stork (Ciconia episcopus) was studied for two seasons (monsoon and winter, 2018–2019) in lowland Nepal to assess how storks coped with changing conditions on farmlands. Activity budgets were prepared from 582 min of video, and recursive partitioning was used to identify variables that affected two critical activities: foraging and vigilance. Foraging was a dominant activity (32 ± 33%) with relatively little percent time spent being vigilant (10 ± 19%). Woolly-necked Storks reduced percent foraging time when they foraged closer (25.8 ± 36.3%) compared to farther (35.8 ± 31.8%) from wetlands. Percent foraging time was reduced during the winter (30.6 ± 35.2%) compared to monsoon (35.1 ± 32.2%), suggesting improved foraging conditions. Percent time spent foraging increased closer to humans, suggesting lower efficiency. Percent time being vigilant decreased closer to wetlands, suggesting reduced disturbance. Wetlands and drier cropfields with human presence were relatively high-value habitats. Woolly-necked Storks coped with changing seasonal conditions in lowland Nepal’s farmlands by altering activity budgets in relatively minor ways identical to alterations made by similar species in wild habitats. This work adds to growing literature showcasing the multifunctional value of tropical agricultural landscapes and underscoring the need to move away from assuming that agriculture is uniformly detrimental for large waterbirds.
... Shapefi les of known rivers, trapeangs (seasonal waterholes) and rice fi elds were obtained. These features were selected due to higher detection of storks around streams and trapeangs inside the sanctuary, and because of the hypothesized importance of rice fi elds, as demonstrated in South Asia (Kitt ur & Sundar, 2020;Ghimire et al., 2021b). Forest cover and land cover were not employed as variables, as deciduous dipterocarp forest is the dominant landscape in the area. ...
... Numerous studies have shown Ciconia species (or at least C. ciconia, C. boyciana and C. episcopus) favour nesting close to human sett lements and crops and are positively associated with traditional agriculture but negatively associated with pesticide use (Ezaki & Sagara, 2014;Kitt ur & Sundar, 2021;Xu et al., 2021). Our study suggests that Asian woollynecks in Cambodia may have habits similar to the species in Nepal, Myanmar and India where positive associations with agricultural landscapes have been reported (Sundar, 2006;Win et al., 2020;Ghimire et al., 2021b). ...
We present the first description of the post-release ranging behaviour of four Asian woollyneck storks Ciconia episcopus released in 2019 in the deciduous dipterocarp forests of Siem Pang Wildlife Sanctuary, Cambodia. Three of the birds were rescued from illegal trade as chicks and the fourth was captive bred and rehabilitated in captivity for five years before release. The birds were fitted with GPS trackers to investigate the ecology and habitat preferences of the species after release. We calculated home ranges for each individual using three different methods (minimum convex polygon, kernel-density estimation & Brownian bridge) and studied correlations between recorded positions and the presence of streams, rice fi elds and waterholes. Combining all methods, we found core-use areas as defined by utilization distribution (UD=50%) ranged from 2.3 to 50.6 km2 (x̄=15.66, SD=13.76), whereas home range as defi ned by UD=95% extended from 8.2 to 254.5 km2 (x̄=89.22, SD=66.00). There was a positive correlation with the presence of forest streams and a weaker correlation with the presence of rice fi elds and waterholes. Survival of two birds for four years and successful breeding in the wild demonstrates that rehabilitation of confiscated Asian woollynecks has conservation value and that Siem Pang Wildlife Sanctuary and equivalent protected areas in Cambodia are suitable reintroduction sites.
... Despite such threats, only a few studies have been conducted to understand the overall composition of birds in wetland habitats. Most of the studies done in the lowland wetlands, especially in the west, are focused on single species like the sarus crane (Grus antigone) (Sharma et al. 2024), lesser adjutant (Leptoptilos javanicus) (Katuwal et al. 2022), Asian wooly neck stork (Ciconia episcopus) (Ghimire et al. 2023(Ghimire et al. , 2021Katuwal et al. 2020), and cotton pygmy-goose (Nettapus coromandelianus) (Dangaura, Chaudhary, and Bhusal 2020). ...
Wetlands serve as crucial habitats for diverse bird species, playing a vital role in maintaining the ecosystem. Geographical location, climate, hydrology, and vegetation composition of wetlands determine the diversity of birds. This study investigated species richness, seasonal diversity, and composition of wetland birds in three prominent water bodies of western Nepal, namely Ghodaghodi, Rani, and Jokhar lakes, from 2021 to 2022 in summer and winter using the point count method. We observed 59 wetland bird species across three wetlands, where both the richness and diversity were significantly higher in the winter. Paired t‐tests revealed significant seasonal differences (p < 0.001) in diversity, species richness, and abundance at both Ghodaghodi and Rani lakes. The highest species richness was observed at Ghodaghodi (n = 58), reflecting its significance as a vital bird habitat. In contrast, diversity was higher in Rani Lake during both seasons (Winter H = 2.98, Summer H = 2.79). NMDS followed by ANISOM test also showed that bird community structure varies across lakes and seasons. Indicator species analysis showed that out of 59 species, 26 species are associated with one or different sites, whereas 18 of them are associated with the summer or winter season. We observed the Anatidae family with the highest relative diversity (RDI = 28.81%) and reported 1 globally vulnerable species and 7 globally near‐threatened species. While in Jokhar Lake, the abundance does not vary between the seasons. This study revealed substantial differences in bird species across seasons and lakes showing that each wetland offers a distinct ecological niche for bird species. The findings reinstate the importance of these wetlands as crucial habitats for the diversity of birds and species composition. This research contributes to the conservation and management of these ecosystems, aiding the protection of wetland birds in Nepal.
... However, how coloniality impacts vigilance behaviour is an important question in the context of building conservation strategies. Storks (Aves: Ciconiiformes), many of which are colonial nesters, are particularly understudied regarding their vigilance behaviour [41][42][43][44][45] . ...
Vigilance in animals, crucial for predator detection, impacts survival and reproduction by diverting time from activities like foraging and mating. Painted Stork (Mycteria leucocephala), a colonially nesting bird, experiences disturbances from avian predators and human presence while nesting in colonies across varied habitats in India. We measured environmental vigilance behaviour at two diverse types of nesting sites in North India, the National Zoological Park and Keoladeo National Park. We studied the study role of several variables viz. sex, nestling age, number of neighbours, number of visitors, and other variables on vigilance, by camera techniques. Our findings revealed significant sex-based differences, with males being more vigilant than females, likely due to their roles in territoriality, mate guarding, and nest protection. Parental vigilance increased as nestlings aged, underscoring its importance as parental investment. Generalized Linear Mixed Models (GLMMs) indicated that number of visitors, number of neighbours, and other habitat variables significantly affected vigilance behaviour. Painted Storks at the National Zoological Park displayed higher vigilance than Storks in Keoladeo National Park, attributed to site specific variables.
... Mao et al. (2018) proved that about 60 % of China's lost natural wetlands were due to agricultural encroachment, and the phenomenon has been found around the world (Chuma et al., 2022;Wang et al., 2022;Yu et al., 2023). Moreover, previous studies had also emphasized the expansion of wetland edges due to various human activities (Assefa et al., 2022;Ghimire et al., 2022). Conversely, impervious surfaces tend to affect the proximity and similarity of wetlands, focusing primarily on affecting the spatial connectivity of wetlands. ...
The Yellow River Delta (YRD) wetland is one of the largest and youngest wetland ecosystems in the world. It plays an important role in regulating climate and maintaining ecological balance in the region. This study analyzes the spatiotemporal changes in land use, wetland migration, and landscape pattern from 2013 to 2022 using Landsat-8 and Sentinel-1 data in YRD. Then wetland landscape changes and the impact of human activities are determined by analyzing correlation between landscape and socio-economic indicators including nighttime light centroid, total light intensity, cultivated land area and centroid, building area and centroid, economic and population. The results show that the total wetland area increased 1426 km2 during this decade. However, the wetland landscape pattern tended to be fragmented from 2013 to 2022, with wetlands of different types interlacing and connectivity decreasing, and distribution becoming more concentrated. Different types of human activities had influences on different aspects of wetland landscape, with the expansion of cultivated land mainly compressing the core area of wetlands from the edge, the expansion of buildings mainly disrupting wetland connectivity, and socio-economic indicators such as total light intensity and the centroid mainly causing wetland fragmentation. The results show the changes of the YRD wetland and provide an explanation of how human activities effect the change of its landscape, which provides available data to achieve sustainable development goals 6.6 and may give an access to measure the change of wetland using human-activity data, which could help to adject behaviors to protect wetlands.
... A coarse assessment of global conservation priorities for storks decades ago identified significant knowledge gaps about most species, especially in Asia (Luthin, 1987). Over thirty years on, there is no assessment of the state of the science for the taxon, although significant strides have been made in understanding conservation requirements of several species (e. g., Ghimire et al., 2021;Kittur and Sundar, 2020;Sundar, 2011;Sundar et al., 2019;Win et al., 2020). Most stork species globally are not considered threatened on the IUCN Red List, which uses a combination of science and expert advice to determine species status. ...
Storks are a conspicuous pan-global freshwater flagship taxon with 20 extant species, all of which have been accorded IUCN Red List status. Red List assessments use a combination of scientific evidence and expert inputs to develop species-level status, but there is little careful evaluation of whether these assessments are comparable across species. Using standard literature databases, we compiled and analysed patterns of research in peer-reviewed literature for all 20 stork species. Our search yielded 989 publications between 1950 and 2022, showing bias in both the coverage of species (66 % covered three stork species) and geographical locations (53.8 % from Europe and the United States of America) despite the highest stork species richness being present in Africa and Asia. Publications on storks, especially from Asia, have increased over time, with 81 % of all studies published since 2000. Most stork research focused on breeding ecology, but was skewed toward only three species. Growing research in Asia showed significant populations of several stork species amid farmlands, suggesting the need to advance similar research in anthropogenically modified landscapes elsewhere. The population and behaviour ecologies of 15 (75 %) stork species remain unstudied. Our review showed scientific evidence varying enormously across stork species, with sparse scientific understanding being the norm. Red List statuses must be made more robust for storks, especially highlighting data-deficient species to help prioritize conservation research, particularly in Africa and Asia, thereby facilitating the development of accurate status assessments for these species.
The marabou stork ( Leptoptilos crumenifer ) is widespread and generally abundant in East and Southern Africa, but recent research has found range loss indicative of a population decline in West Africa in recent decades. In the absence of population data, we conducted an in‐depth review of the status of the marabou in the region using a plethora of sources together comprising the largest database on the occurrence of the species. Despite caveats and coarseness of the assessment, we estimate the range loss at 52% in West Africa, including extirpation of approximately 64% of known nesting colonies since 2000. The resulting fragmentation has left a metapopulation of likely no more than 100 breeding pairs in The Gambia and Benin and an unknown number of breeders in Cameroon. Knowledge gaps about marabou population ecology in West Africa are significant and prevent an empirical assessment of regional extinction probability. Therefore, we recommend immediate field surveys, especially for breeding colonies, and research into threats and population dynamics. We also recommend the West African metapopulation be listed as regionally critically endangered and that a working group be formed comprising stakeholders from across the region to aid in assessing threats and implementing research and conservation action.
Wetland and agricultural landscapes provide prime habitats for a variety of waterbirds. In tropical and subtropical areas, such landscapes experience considerable variation due to seasonal changes in water availability and crops. We asked how the Rednaped Ibis Pseudibis papillosa, an endemic and poorly studied waterbird that is assumed to not be closely tied to wetlands, coped with seasonal changes in a semiarid region of India. We hypothesized that ibises respond differently to seasonal changes when the dominant land use varied (wetlands versus agriculture). We documented Rednaped Ibis abundance (as encounter rate), flocking and habitat use across three seasons in Udaipur district, Rajasthan, India. We used an apriori field design that allowed coverage of focal areas that were dominant in either wetlands or agriculture. In all three seasons, wetlanddominated areas had magnitudes more ibises relative to agriculturedominated areas. Ibises showed strong seasonal variation in encounter rates, flock size, and habitat use in both landscapes. Rednaped Ibis preferred wetland habitats throughout the year, though a majority were sighted in fallow fields with none using fields with standing crop in either landscape. Our findings suggest that Rednaped Ibis are closely associated with wetlands and that seasonal variations in landscape conditions, especially occurrence of fallow fields, cause ibises to change some of their habits. Existing literature on the species' habits require being updated. Similar careful studies conducted in a variety of conditions are essential to understand if coping mechanisms of Rednaped Ibis vary with crop type and local climate.
The Red-naped Ibis Pseudibis papillosa is one of the least studied large South Asian wading birds. The species is categorized as a fairly common species in Nepal but there has not been a careful assessment to estimate its population, understand population trends, the species' habitat requirements and conservation status in Nepal. In this study, we provide novel empirical information on Red-naped Ibis use of lowland Nepal's agricultural landscapes with an intent to develop a preliminary assessment of its status. In 2018, we established 100 transects of 500m length each in agricultural landscapes of four districts and these were monitored seasonally until 2022 for a total of 875 transects. Red-naped Ibis were sighted in 137 transects with more sightings in Kapilvastu (34% of transects) and during the monsoon (36%), while the least sightings were in the Sarlahi district (12%) and during the summer (30%). Flock sizes ranged from 1 to 17. In 2022, 14 nests were discovered in eight districts, the majority of which were outside protected areas (57%) with Red-naped Ibises mostly nesting in forests (36%). Most nests were located on Bombax ceiba (50%) and Shorea robusta (29%), and the mean height of nesting trees was 20.28 meters. Our research suggests that Red-naped Ibis are widespread and resident, but not abundant on Nepal's agricultural lands.
Conservation of biodiversity alongside agriculture is now a global priority. Tree-nesting waterbirds have a tenuous relationship with farmlands because their survival requires farmers to retain trees and wetlands amid croplands. Research on such birds is rare on tropical and sub-tropical agricultural landscapes where high human densities and intensive farming ostensibly deteriorate breeding conditions. We explored breeding ecology and nest site selection by the single-nesting Woolly-necked Stork (Ciconia episcopus) in Haryana, north India using 298 nests from 166 locations discovered between 2016 and 2020. We determined the relative strengths of association of nest locations with natural features (trees, wetlands), human presence (habitation) and artificial water sources (irrigation canals) to understand cues used by breeding storks to situate nests. Woolly-necked Stork brood size from 42 successful nests was relatively high (3.1 ± 0.9 SD), with nests close to human habitation and wetlands having smaller broods. Storks showed high nest site fidelity (44.5% of sites used > 1 year), rarely nested on man-made structures (electricity pylons; 8.4%), and distributed nests in a clumped pattern. Woolly-necked Storks situated nests ambivalent to natural features but associated strongly with man-made features (positively with irrigation canals; negatively with human habitation). Contrary to expectations, most nests were not on the tallest trees but on the medium sized, native Dalbergia sissoo though storks situated nests on two tall trees (native Ficus religiosa and exotic Eucalyptus sp.) far more than the trees’ availability. All three tree species were favoured either for traditional agroforestry or local religious beliefs. Traditional agriculture in Haryana supported a substantial breeding population of Woolly-necked Storks facilitated by agriculture-related components rather than existing natural features. This novel scenario contradicts conventional narratives that suggest multi-season small holder tropical and sub-tropical agriculture degrades breeding conditions for waterbirds. Our findings in Haryana reiterate the need to assemble a diverse conservation toolkit of different locally relevant mechanisms supporting biodiversity amid cultivation.
The Asian Woollyneck Ciconia episcopus is a stork found throughout Asia whose international conservation status is currently being considered for reclassification from vulnerable to near-threatened. However, much of what is known about this species is fragmented across observational reports and small studies making a comprehensive assessment of population trends difficult. Here, we bring together all available published information to see what is known and what research questions still need answering in order to make reliable assessments of regional population trends and identify probable drivers of decline. Despite the species likely being extinct in the extremes of its former range and evidence of dramatic declines in Southeast Asia, Asian Woollyneck appears to be stable or increasing in India, Sri Lanka and Nepal. Observations of its preferred foraging and nesting habitats in South versus Southeast Asia show some obvious differences that may explain regional variations in population trends. In South Asia the bird is common in open grasslands and agricultural areas, while in Southeast Asia it is mostly observed in forested areas. Also, reports of the Asian Woollyneck nesting on cell phone towers is increasing in South Asia. However, because of a severe lack of reporting from Southeast Asia, it is unclear if or how these regional differences in population trends and habitat use are linked. Structured surveys and studies into the Asian Woollyneck foraging, nesting and movement ecology are urgently needed to understand the extent and drivers of decline in Southeast Asia. Therefore, researchers should focus future studies on population trends across the species' range, and aim to identify the local factors influencing recent changes in population growth. Without such knowledge, reassessment of its conservation status may be premature.
Rangewide distribution patterns and environmental requirements of the African Ciconia microscelis and Asian C. episcopus Woollyneck Storks are poorly understood, which has confounded the ability to develop empirical conservation status assessments for either species. We collated thousands of records for each species to create the first objective distribution maps, and used these data to model environmental suitability at the continental and regional scales in Africa and Asia with the machinelearning program MaxEnt. We found the African Woollyneck to be fairly widespread in southern and East Africa but its distribution in West Africa was fragmented. The Asian Woollyneck had a widespread distribution in south Asia, an isolated population segment in Cambodia and Vietnam, and was sparsely distributed on the southeast Asian islands. Predictions of suitable distributions and responses to climate variables in the MaxEnt models were scaledependent for both species. Annual and seasonal precipitation were most important in Africa, and the most influential variables differed across Asian models. Field studies testing these findings will bolster the knowledge of ecological requirements, as well as help determine how responses to environmental variation influence population dynamics. While our findings indicate neither species are of immediate conservation concern, there is evidence of population declines and range fragmentation and contractions in some regions. Understanding factors that have caused these changes is especially important in the face of ongoing environmental change on both continents.
Crowded agricultural landscapes of the tropics and subtropics are assumed to be responsible for the decline of many waterbird species. This includes Woollynecked Storks, one of the least studied large waterbirds, with no longterm multiscale information on its ecology. In this study we provide densities, population size, flock size and habitat use of the species in agricultural landscapes across seven districts in lowland Nepal and India using the largest available field data set of Woollynecked Stork observations (N = 8,906 individuals in 3,133 flocks observed seasonally between 2014 and 2019). With this data, we asked whether these metrics showed variation by season and location. Woollynecked Stork densities fluctuated considerably, both with season in each location and across locations. Estimated population of Woollynecked Storks in the study area was 1,689 ± 922 (SD) which extrapolated to the known distribution range of the species in south Asia provided a coarse population estimate of 2,38,685 ± 1,24,471 (SD). Woollynecked Storks were seen mostly in small flocks of 14 birds (86% of flocks) with few extraordinarily large flocks. Flocks were significantly larger in Jhajjar and Kheda districts, in winter, and in fallow fields and wetlands. Most Woollynecked Storks were observed in agriculture fields (64% of 1,874 observations) with much fewer in wetlands (9%). In three locations where seasonal habitat use was measured, Woollynecked Storks varied habitat use seasonally in all locations. Of six locations where habitat preference was assessed, storks preferred wetlands in five locations. Results of this study suggest that the largest known global population of this species is resident in agricultural landscapes, and coarse population estimates suggests that the population size of this species was previously underestimated. Results also showed considerable variations in flock size and habitat use with location and season suggesting that Woolly necked Storks show plasticity in response to changing conditions on agricultural landscapes. These findings will be helpful to revise the species' status assessment and understanding its conservation requirements.
Provides a detailed background to the conservation status and ecological understanding available on Woolly-necked Storks, and showcases the value of replacing assumptions with field data. Underscores some incorrect assumptions regarding the conservation needs of the species, provides an update (with references from the Special Section of the same issue, and additional references), and provides a roadmap for improving the understanding of this species.
Crowded agricultural landscapes of the tropics and subtropics are assumed to be responsible for the decline of many waterbird species. This includes Woollynecked Storks, one of the least studied large waterbirds, with no longterm multiscale information on its ecology. In this study we provide densities, population size, flock size and habitat use of the species in agricultural landscapes across seven districts in lowland Nepal and India using the largest available field data set of Woollynecked Stork observations (N = 8,906 individuals in 3,133 flocks observed seasonally between 2014 and 2019). With this data, we asked whether these metrics showed variation by season and location. Woollynecked Stork densities fluctuated considerably, both with season in each location and across locations. Estimated population of Woollynecked Storks in the study area was 1,689 ± 922 (SD) which extrapolated to the known distribution range of the species in south Asia provided a coarse population estimate of 2,38,685 ± 1,24,471 (SD). Woollynecked Storks were seen mostly in small flocks of 14 birds (86% of flocks) with few extraordinarily large flocks. Flocks were significantly larger in Jhajjar and Kheda districts, in winter, and in fallow fields and wetlands. Most Woollynecked Storks were observed in agriculture fields (64% of 1,874 observations) with much fewer in wetlands (9%). In three locations where seasonal habitat use was measured, Woollynecked Storks varied habitat use seasonally in all locations. Of six locations where habitat preference was assessed, storks preferred wetlands in five locations. Results of this study suggest that the largest known global population of this species is resident in agricultural landscapes, and coarse population estimates suggests that the population size of this species was previously underestimated. Results also showed considerable variations in flock size and habitat use with location and season suggesting that Woolly necked Storks show plasticity in response to changing conditions on agricultural landscapes. These findings will be helpful to revise the species' status assessment and understanding its conservation requirements.
Asian Woollyneck Ciconia episcopus is a globally threatened stork found across south and southeast Asian countries. In Nepal, it is considered as a fairly common resident species although
categorized as ‘NearThreatened’. Here, we report on Asian Woollyneck occurrences in 116 transects (farmland100, forest8, river8)
each measuring 500 m across four districts of lowland Nepal
(Kapilvastu, Chitwan, Sarlahi and Sunsari) and surveyed in multiple seasons from April 2018 to December 2019 for a total of 985 transect counts. Despite our extensive survey, we recorded Asian Woollynecks in only 14 transect counts of which eight were along the buffer zone of Chitwan National Park (CNP). All sightings were of small flocks with 1-2 storks. Majority of the sightings (85%) were in farmlands, remaining in river but not in forest. We observed one nest on a Sal Shorea robusta tree along the buffer zone of CNP in 2019 from which one chick fledged in early October. Our study adds to the meager information available on Asian Wollyneck in Nepal and indicates that this species is sparsely distributed in the lowland farmlands.
Provides a detailed background to the conservation status and ecological understanding available on Woolly-necked Storks, and showcases the value of replacing assumptions with field data. Underscores some incorrect assumptions regarding the conservation needs of the species, provides an update (with references from the Special Section of the same issue, and additional references), and provides a roadmap for improving the understanding of this species.
Cereal farming is on the increase globally, and trees on these agricultural landscapes are selectively removed by farmers. Waterbird populations, supported on many cereal farmlands, need trees to place heronries and can be impacted by farmers’ habits. In a cereal-dominated landscape in lowland Nepal, a landscape-scale field design was used to quantify characteristics of existing trees (density, species, girth, height), and contrasted against heronry trees to understand how choice of nest trees by select Ciconiiformes species was affected by farmers’ habits. Tree density was patchy and tree species richness low, dominated by two tree species that had direct utility to farmers (Dalbergia sissoo – timber; Mangifera indica – fruits). Heronries were preferentially located on two wild tree species that were 8% of available trees and were either revered in local religion (Ficus religiosa; 6% of all heronries) or favored for agroforestry (Bombax ceiba; 42%). Heronries were preferentially located on larger trees. Availability of suitable trees for heronries was reduced by farmers’ habits, but religious beliefs and agroforestry continued to support multi-functionality of cereal-dominated cropfields in lowland Nepal.
Agricultural landscapes in south Asia have high human densities, experience year-round cropping, and the few remaining wetlands experience heavy human use. Factors affecting the breeding success of colonially-nesting waterbirds in such conditions are poorly understood. Using Bayesian Network (BN) models, we explored the importance of colony size, extent of persisting wetlands, human influence as proximity to habitation, and variation in landscape conditions due to changing crops (season) on the breeding success of two stork species-the Asian Openbill Anastomus oscitans and the Lesser Adjutant Leptoptilos javanicus-in lowland Nepal. Hypotheses were framed a priori to understand relative influences of each variable on breeding success, and to determine if heavily-used wetlands could ameliorate effects due to colony size and human presence. The model with all four covariates had best performance for both species, underscoring that complex combinations of factors affected stork breeding success in Nepal. In line with expectations, the importance of covariates differed between species. Proximity to human habitation and progression of season best explained breeding success for Asian Openbills, while season and the extent of wetlands around colonies best explained Lesser Adjutant breeding success. Wetland extent mediated some of the density-dependent effects, and also ameliorated effects linked to proximity to human
In response to wetland degradation in the middle and lower reaches of Yangtze River floodplain, wintering waterbirds move to artificial wetlands. Exploring changes in behavior associated with habitat shifts can further understanding of waterbird adaptation to anthropogenic landscapes with frequent disturbances. In winter 2017–2018, vigilance patterns in Bean Goose (Anser fabalis) and White-fronted Goose (Anser albifrons) were quantified in natural and artificial habitats in Shengjin Lake, one of the typical Yangtze-connected lakes in China. No significant difference in percentage time spent vigilant between species was found, but vigilance frequency of White-fronted Goose was higher than Bean Goose. Percent time spent vigilant and mean scan durations in both species were higher in rice fields (Bean Goose: 15.3% ± 2.0 SE and 12.3 sec ± 1.6 SE; White-fronted Goose: 15.7% ± 2.8 SE and 8.6 sec ± 1.4 SE) than in natural wetlands (Bean Goose: 7.8% ± 1.9 SE and 5.7 sec ± 1.1 SE; White-fronted Goose: 9.8% ± 1.2 SE and 6.4 sec ± 0.7 SE), while no significant difference was found in vigilance frequency between the two habitats. Flock size was a negative predictor of the three vigilance components.
Wetlands in arid landscapes provide critical habitat for millions of migratory waterbirds across the world and throughout their annual cycle. the scope and scale of understanding avian use of these wetlands in conjunction with changes in climate are daunting yet critical to address lest we lose continent-wide migratory pathways. Here, we assess changes in waterbird use of North America's Pacific Flyway in the Great Basin by examining water availability and climate trends over the past 100 years. We found recent (1980-2015) climate warming has significantly reduced the amount and shifted seasonality of water flowing into wetlands. Further, we found remarkable changes in waterbird species composition over time. We propose that a reduced hydroperiod and lower water quality from reduction in water level and flow limits sites used by waterbirds. These factors reduce chick survivorship as they cannot metabolize saline water, which makes suitable freshwater conditions a limiting resource. Collectively, climate-induced changes in Great Basin wetlands suggest a major shift in freshwater ecosystems, resulting in degradation of a continental migratory route. This work illustrates the importance of examining multi-scale changes in critical regional resources to understand their impact across a hemispheric flyway and provides a model to examine other flyways.
The roosting ecology of most waterbird species is poorly known and even less is known from southern Asia, where many species inhabit human-modified areas. Roosting ecology of the Black-headed Ibis (Threskiornis melanocephalus) was studied in urban and rural settings in southern Rajasthan, India. Analyses focused on assessing whether site characteristics varied between nest sites, urban and rural roost sites, and paired sites (i.e., a waterbird roost site near Black-headed Ibis roosts but without Black-headed Ibis). Additionally, the hypothesis that factors affecting Black-headed Ibis numbers at roosts would be similar at urban and rural sites was tested. Tree characteristics (canopy cover, girth at breast height) were different (P < 0.05) between nest and roost sites. Urban roost sites experienced 2.3 times greater disturbance than rural roost sites. Paired site characteristics were similar to urban roost sites (multi response permutation procedure, significance of δ = 0.3), but were dissimilar to rural roost sites. Co-occurring roosting bird assemblages were significantly different between roosts and paired sites (significance of δ < 0.01) in urban and rural settings. Black-headed Ibis numbers at urban roosts were influenced by multiple variables, but models showed considerable ambiguity at rural sites. Results strongly suggest that including roost sites in a species status assessment is important.
The Endangered Red-crowned Crane (Grus japonensis) is one of the most culturally iconic and sought-after species by wildlife tourists. Here we investigate how the presence of tourists influence the vigilance behaviour of cranes foraging in Suaeda salsa salt marshes and S. salsa/Phragmites australis mosaic habitat in the Yellow River Delta, China. We found that both the frequency and duration of crane vigilance significantly increased in the presence of wildlife tourists. Increased frequency in crane vigilance only occurred in the much taller S. salsa/P. australis mosaic vegetation whereas the duration of vigilance showed no significant difference between the two habitats. Crane vigilance declined with increasing distance from wildlife tourists in the two habitats, with a minimum distance of disturbance triggering a high degree of vigilance by cranes identified at 300 m. The presence of wildlife tourists may represent a form of disturbance to foraging cranes but is habitat dependent. Taller P. australis vegetation serves primarily as a visual obstruction for cranes, causing them to increase the frequency of vigilance behaviour. Our findings have important implications for the conservation of the migratory red-crowned crane population that winters in the Yellow River Delta and can help inform visitor management.
Wetland ecosystems, particularly the mangrove forest, are the primary wild habitat of heronry birds. However, urban ecosystems have become a favourite breeding habitat of these birds. To provide inputs into the habitat management for conservation of these birds, we investigated the quantitative and qualitative characteristics of nesting trees of heronry birds in the urban environment of the North Kerala region of peninsular India. Census on nesting trees was done in three major microhabitats of the urban ecosystem: avenues of national highways and towns, non-residential plots, and residential areas apart from the mangrove islets in the peri-urban locality. The study found that 174 trees of 22 species hosted 1928 heronry bird nests in the urban habitats; mangrove forests, although plentiful in the study area, hosted only about 20% of the total nests encountered in the study. Rain-Trees (Samanea saman; 43.7%) were the most available nesting tree. The greatest number of nests and nesting trees were encountered on the roads of urban areas, followed by non-residential areas and residential areas. The differences in the observed frequencies of nesting trees in three microhabitats and in three types of roads (national highways > state highways > small pocket road) were significant. Canopy spread, girth size, and quality of the trees predicted the tree selection of the heronry birds in urban environments. Therefore, we recommend proper management and notification of the identified nesting trees as protected sites for the conservation of herorny birds.
The main objectives of this national Bird Red Data Book are to provide comprehensive accounts of all the bird
species found in Nepal, assess their status applying the IUCN Guidelines at Regional Levels (IUCN 2003),
identify threats to bird species and recommend the most practical measures for their conservation. The
species nomenclature in this Red Data Book follows IUCN approved names which are the same as those used
by BirdLife International.
The Yangtze River floodplain provides important wintering habitats for Hooded Cranes (Grus monacha) in China. Fluctuations in the water level change foraging habitat and food availability, affecting their temporal-spatial patterns of foraging activities. It is of considerable importance to investigate the effect of these fluctuations on food availability for wintering Hooded Cranes and their foraging response to these changes. Understanding their behavior patterns is beneficial in protecting the wintering crane population and restoring their wintering habitats.
A field survey of the winter behavior of cranes was carried out at Shengjin Lake from November in 2013 to April in 2014. Habitat variables, as well as the spatial distribution and behavior patterns of wintering cranes at their foraging sites during five stages of water level fluctuation were collected. Based on this data we analyzed the relationship of foraging behavior relative to water level fluctuations and habitat types.
The foraging habitats used by Hooded Cranes varied at the different water level stages. As the water level decreased, the use of meadows and mudflats increased. When the water dropped to its lowest level, the use by the Hooded Crane in the mudflats reached a peak. There were statistically significant differences in time budget in the three types of habitats over the five stages of the water level. In the mudflats, the foraging behavior and maintenance behavior varied significantly with the water level, while the alert behavior showed little variation. Analysis of a generalized linear model showed that the five water level stages and three habitat types had a significant effect on foraging behavior, while the combined effect of these two variables was significant on the foraging time budget and the length of foraging activity of the Hooded Crane.
With the decrease in the water level, the use of mudflats by Hooded Cranes increased correspondingly. Food availability in different habitats was affected by changes in the water level. The Hooded Crane adjusted its foraging patterns and made full use of the three available types of habitat in order to acquire enough food in response to fluctuations in the water level.
Time-activity budget of the Black-necked Storks was studied from January 1995 till June 1997 in Dudwa National Park, Uttar Pradesh, India. Black-necked Storks spent nearly 46% of their time resting. Except chasing, resting and drinking, no other activity differed significantly among storks in three years. Black-necked Storks spent more time for resting and drinking in summer (April, May and June) and chasing was more in winter (February and March). Time taken for resting varied between habitats among different pairs (N=3). Variations in time budget of Black-necked Storks were correlated with prey availability. Time spent foraging did not vary significantly during the study period and storks had a irregular feeding pattern, greatly influenced by other fish-eating birds. When food availability increased, congregation of other fish-eating birds also increased leading to the conflict with storks. The storks became aggressive when they tried to defend their territory from other fish-eating birds. Most of the aggressive encounters were observed between 0600 and 1000hr.
Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012-13 and 2013-14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain.
We studied effects of disturbance on migrating waterbirds during spring on Cumberland Pool at Tishomingo National Wildlife Refuge, Tishomingo, Oklahoma, USA, 1999 and 2000. We recorded 240 disturbances in 477.5 hr of observation of American coots (Fulica americana), American white pelicans (Pelecanus erythrorhynchos), black terns (Chlidonias niger), blue-winged teal (Anas discors), and Franklin's gulls (Larus pipixcan). Recreation (n = 208) accounted for 86.7% of all disturbances, natural disturbances (n = 23) accounted for 9.6%, and 3.3% of disturbances (n = 8) were unknown. Boat fishing increased alertness by American white pelicans but did not affect escape behavior. Recreational disturbances caused increases in escape activities and alertness of American coots. However, only boat fishing increased energy expenditure by American coots. Rates of disturbance differed between species and appeared to be correlated to foraging strategies, habitat requirements, and type of disturbance. Therefore, managers of public lands should consider habits and migration chronologies of waterbirds when setting seasonal recreation dates. Modifying recreation policy could reduce rates of disturbance to some waterbirds. Future research should be aimed at constructing energy budgets and measuring body condition of birds at multiple staging areas during spring to determine whether recreational disturbance ultimately affects reproductive success.
The Ibisbill (Ibidorhyncha struthersii) is a rare shorebird uniquely adapted to high-altitude river rapids. Ibisbill has received little study as a result of its isolation and the inaccessibility of its habitat. The habitat utilization, time budgets and daily rhythm of Ibisbill were studied in the southwestern part of Sichuan Province, China, in July to August 2008 and January to February 2010. A total of 55 Ibisbills were recorded in summer and 87 in winter. Encounter rates and group size were similar in summer and winter, but habitat selection differed. In summer, most Ibisbills chose central islands in rivers that had many large stones offering opportunities for both camouflage and physical concealment, and riverside pasture covered by weedy growth with abundant insects making them suitable for foraging. In winter, when water levels are low and many stony beaches are exposed, Ibisbills were more often encountered on riverbanks. Foraging (48.9%) and resting (32.3%) were the most commonly observed behaviors, and the time that Ibisbills spent on foraging (t19 = -4.0, P = 0.001) in winter was significantly higher than in summer. In winter, Ibisbills spent less time engaged in locomotion (t19 = 5.1, P = 0.001) and resting (t19 = -2.8, P = 0.012). Alertness increased toward sunset in summer but not in winter.
Variable time budgets and foraging behaviour were observed in a marine diving bird, the rhinoceros auklet Cerorhinca monocerata, in response to intraseasonal and interannual variations in prey abundance and distribution. Few studies have simultaneously measured the spatial dispersal of seabirds at sea, time budgets at sea and prey abundance and distribution. Time budgets and foraging behaviour were deterrnined through visual scans. Prey abundance, estimated hydroacoustically during marine transects, was similar among years, but prey was dispersed over larger spatial areas in 1997 than in 1995 and 1996. Rhinoceros auklets were also dispersed over larger spatial areas in 1997 and fewer mixed-species feeding flocks were formed. In 1997, rhinoceros auklets increased the time spent foraging, decreased the recovery periods between successive dives, and were more strongly associated with prey at larger spatial scales. This suggested that auklets were working hard while foraging but were less successful at locating and maintaining contact with prey when prey was more dispersed. In 1996, there was a period (June 13 to 20) when fish schools were common near the surface, during which auklets spent more time foraging and formed more feeding flocks. This suggested that auklets were working hard to take advantage of this readily available prey. This paper iilustrates the importance of behavioural plasticity and time budget flexibility for seabirds Living in highly variable environments.
Habitat loss and degradation are critical threats for the globally threatened White-naped Crane Grus vipio. We estimated the size of the area used per day and the time budgets of parental and non-parental White-naped Crane pairs in north-eastern Mongolia during 2000 and 2001. Six parental crane pairs used an area of 11–155 ha per day. The maximum distance of a focal parental crane from the roosting-site was 3,030 m. Habitat conservation measures for breeding White-naped Cranes need to be targeted to within at least 3 km of the roosting-site or nest-site. Parental cranes spent 79.6 ± 4.8% of the daylight period foraging and had reduced preening and resting behaviour to 4.4 ± 1.9%. Pairs without juveniles showed a pronounced period of resting and preening behaviour during midday, which was absent in parental cranes. This indicates that parental cranes may be time-stressed. We conclude that increases in feeding-related activities (e.g. caused by a decrease in food availability) are likely to be at the expense of parental vigilance. Conversely, increases in vigilance (due to e.g. increased disturbance) may have a negative impact on feeding-related activities. Both increases can potentially negatively affect reproductive success in this Vulnerable species.
The migratory white stork (Ciconia ciconia) became extinct in Switzerland in 1950. A reintroduction project with intensive management (translocation, prevention of migration, artificial feeding) started in 1948, and 175 pairs were breeding in 2000. For the period 1973–2000 we estimated annual survival rates and fledging success to estimate the population growth rate by a stochastic matrix projection model. Compared to other populations, adult survival rate (0.86, with 95% CI: 0.81–0.89) was very high and little variable over time, juvenile survival (0.37, CI: 0.31–0.43) was comparable to other populations whereas the average fledging success was low (1.65) but strongly variable over time. The population growth rate was positive, indicating that the population is self-sustainable at the moment. The growth of the white stork population was largely favoured by the high adult survival which more than compensates for the low fledging success. The population growth rate is particularly sensitive to changes in adult survival, but it would be very difficult to improve this further with management. However, maintenance of the high adult survival is crucial and an improvement in fledging success seems important for the long-term persistence of the white stork population in Switzerland. Fledging success depends on habitat quality, and thus restoration of breeding habitats should be the main management activity in the near future.
Predation directly triggers behavioural decisions designed to increase immediate survival. However, these behavioural modifications can have long term costs. There is therefore a trade-off between antipredator behaviours and other activities. This trade-off is generally considered between vigilance and only one other behaviour, thus neglecting potential compensations. In this study, we considered the effect of an increase in predation risk on the diurnal time-budget of three captive duck species during the wintering period. We artificially increased predation risk by disturbing two groups of 14 mallard and teals at different frequencies, and one group of 14 tufted ducks with a radio-controlled stressor. We recorded foraging, vigilance, preening and sleeping durations the week before, during and after disturbance sessions. Disturbed groups were compared to an undisturbed control group. We showed that in all three species, the increase in predation risk resulted in a decrease in foraging and preening and led to an increase in sleeping. It is worth noting that contrary to common observations, vigilance did not increase. However, ducks are known to be vigilant while sleeping. This complex behavioural adjustment therefore seems to be optimal as it may allow ducks to reduce their predation risk. Our results highlight the fact that it is necessary to encompass the whole individual time-budget when studying behavioural modifications under predation risk. Finally, we propose that studies of behavioural time-budget changes under predation risk should be included in the more general framework of the starvation-predation risk trade-off.
Recursive partitioning methods have become popular and widely used tools for nonparametric regression and classification in many scientific fields. Especially random forests, which can deal with large numbers of predictor variables even in the presence of complex interactions, have been applied successfully in genetics, clinical medicine, and bioinformatics within the past few years. High-dimensional problems are common not only in genetics, but also in some areas of psychological research, where only a few subjects can be measured because of time or cost constraints, yet a large amount of data is generated for each subject. Random forests have been shown to achieve a high prediction accuracy in such applications and to provide descriptive variable importance measures reflecting the impact of each variable in both main effects and interactions. The aim of this work is to introduce the principles of the standard recursive partitioning methods as well as recent methodological improvements, to illustrate their usage for low and high-dimensional data exploration, but also to point out limitations of the methods and potential pitfalls in their practical application. Application of the methods is illustrated with freely available implementations in the R system for statistical computing.
Western Tennessee is an important region for waterfowl during non-breeding periods, supporting >40% of the Mississippi Flyway population of American black ducks (Anas rubripes). Understanding habitat selection and activities of waterfowl during the non-breeding period is important for directed habitat management on national wildlife refuges and in other wetlands important in meeting regional waterfowl conservation objectives. During November–February 2011–2013, we investigated diurnal habitat selection and activities of dabbling ducks (Anatini) among 5 common wetland types relative to emergent cover, water depth, and energetic carrying capacity (i.e., duck energy days [DEDs]) in western Tennessee, USA. We observed waterfowl daily and sampled food resources monthly at Tennessee and Cross Creeks National Wildlife Refuges. Mallard (Anas platyrhynchos), gadwall (A. strepera), northern pintail (A. acuta), and American green-winged teal (A. carolinensis) selected moist-soil wetlands over wooded, aquatic bed, and open water wetland types. Gadwall also selected deeper wetlands containing submersed aquatic vegetation. Foraging was the dominant activity of all dabbling ducks in mudflats and moist-soil wetlands, and it was also dominant in wooded wetlands for green-winged teal and gadwall. Deep, open water was avoided by dabbling ducks. Selection of wetland types was negatively correlated with increasing water depth and positively correlated with increasing emergent cover and DEDs. Shallowly flooded moist-soil and wooded wetlands provide high-energy foods and dense emergent cover, and are important to a diversity of dabbling ducks during winter.
The ecology of stork colonies in southern Asia are very poorly understood. Factors affecting provisioning times of adults were evaluated at nests of two stork species, the Asian Openbill (Anastomus oscitans) and the Lesser Adjutant (Leptoptilos javanicus), in lowland Nepal, where the landscape is dominated by multi-cropped agriculture fields. Analyses focused on understanding if provisioning times were influenced more due to colony-level variables, wetlands around colonies, or season. Using generalized additive mixed models and the information-theoretic approach, colony-level variables (brood size and chick age) showed non-trivial associations with provisioning times (substantially better than the null model). Univariate models with colony size and wetlands had poor support (worse than the null model). Season, which represented the changing cropping patterns, rainfall, and wetness on the landscape, was the most important variable for both species. The combination of season and wetlands was very important for provisioning Asian Openbills whose chicks fledged during the monsoon (July-October), but not for Lesser Adjutants whose chicks fledged in the drier winter months (November-February). Results strongly suggest that changing cropping patterns to a drier monsoonal crop, or reductions in wetland extents, will be detrimental to storks in Nepal.
The IUCN (International Union for Conservation of Nature) Red List classifies species according to their risk of extinction, informing global to local conservation decisions. Unfortunately, important geospatial data do not explicitly or efficiently enter this process. Rapid growth in the availability of remotely sensed observations provides fine-scale data on elevation and increasingly sophisticated characterizations of land cover and its changes. These data readily show that species are likely not present within many areas within the overall envelopes of their distributions. Additionally, global databases on protected areas inform how extensively ranges are protected. We selected 586 endemic and threatened forest bird species from six of the world's most biodiverse and threatened places (Atlantic Forest of Brazil, Central America, Western Andes of Colombia, Madagascar, Sumatra, and Southeast Asia). The Red List deems 18% of these species to be threatened (15 critically endangered, 29 endangered, and 64 vulnerable). Inevitably, after refining ranges by elevation and forest cover, ranges shrink. Do they do so consistently? For example, refined ranges of critically endangered species might reduce by (say) 50% but so might the ranges of endangered, vulnerable, and nonthreatened species. Critically, this is not the case. We find that 43% of species fall below the range threshold where comparable species are deemed threatened. Some 210 bird species belong in a higher-threat category than the current Red List placement, including 189 species that are currently deemed nonthreatened. Incorporating readily available spatial data substantially increases the numbers of species that should be considered at risk and alters priority areas for conservation.
The time budgets, behavior rhythms, foraging habitats and food preferences of oriental white stork Ciconia boyciana were studied from December 2013 to March 2014 with instantaneous scan sampling and focus animal sampling methods at Poyang Lake, Jiangxi province, China. The results showed that the main behavior of oriental white stork were resting (40.07 +/- 3.21%) and foraging (35.44 +/- 2.42%), followed by moving (13.46 +/- 1.01%) and preening (9.05 +/- 0.62%). The patterns of time budgets were similar in early and later wintering periods. Daily minimum temperature showed a significant linear relationship with foraging and resting. Foraging was significantly positively correlated with daily minimum temperature, and resting was significantly negatively correlated with daily minimum temperature, which indicated that minimum temperature was the key factor affecting stork behavior in winter. Foraging behavior peaked at 7:00-7:59 and 16:00-16:59 hours and resting peaked at 11:00-11:59 hour. Oriental white stork foraging habitats varied in different months and gradually shifted from shallow water to grassland. Their average moving rate was 17.86 +/- 0.61 steps/min, pecking rate was 8.31 +/- 0.25, and pecking success rate was 1.03 +/- 0.04 pecks/min. In shallow water, average pecking rate was significantly positively correlated with moving rate and pecking success rate. In mudflats and grasslands, moving rate was significantly negatively correlated with pecking success rate. We argued that oriental white stork use different foraging methods and prey capture techniques in different habitats, possibly because food resources in mudflats and grasslands differ from those in shallow water. The oriental white stork mainly preyed on fish in shallow water, and it handled large-sized fishes (>15 cm) for 201.07 +/- 35.31 sec (n=23), and small-sized fishes (<15 cm) for 85.22 +/- 20.86 sec (n=14).
The number of White Storks (Ciconia ciconia) has been decreasing in many parts of Europe at least since the middle of the 20th century. Intensification of agriculture and continuous conversion of natural habitats, such as wetlands, into agricultural landscapes have been recognized as the most important determinants of dramatic reductions in population sizes of this species. For this reason, providing quantitative estimates of habitat requirements may allow us to identify the key biota which should be prioritized for conservation. The aim of this study was to investigate White Storks' habitat selection in a mosaic agricultural landscape in central Poland. We found that territories associated with large river valleys were highly preferred by first-arriving storks. We also recorded lower intensity of brood reduction and higher reproductive success of storks breeding in such territories. Thus, it seems likely that location of nests close to river valleys provided easy access to rich food resources associated with wetlands. In fact, distance to nearest wetland was the second strongest predictor of nest-site selection in the studied population. We also demonstrated that pairs nesting in the territories with a high proportion of wetlands showed lower levels of brood reduction in comparison to pairs having poorer access to wet habitat patches. Finally, we found that although early arriving storks avoided settling in an urbanized landscape, they selected nesting sites located close to buildings. The results of this study confirmed high importance of wet grasslands for the core central European population of White Storks.
Arenaria interpres on a Pacific beach in Costa Rica foraged only when the tidal flat was exposed; they rested in flocks during high tide. Flock size, peck rate and success rate decreased during the ebb and increased with the flood. Foraging velocity increased until low tide, then decreased. Vigilance was related only to flock size; flock size did not affect foraging rates or success. Vigilance did not directly reduce foraging efficiency or deter flock breakup, but increased aggression, decreased foraging efficiency and may have partly caused reduction in flock size. Turnstones fed on invertebrates close inshore and on crabs farther out on the flat, where the latter were more abundant. Rates of predation on crabs were correlated with crab density, decreased foraging rate and success. The switch in the birds' diet and the substrate zonation appeared to be largely responsible for the tidally and spatially correlated patterns in foraging rate. Possibly the nature and distribution of the prey influenced the turnstones' levels of aggression and hence determined optimal flock sizes.-from Author
Biodiversity persistence in non-woody tropical farmlands is poorly explored, and multi-species assessments with robust landscape-scale designs are sparse. Modeled species occupancy in agricultural mosaics is affected by multiple factors including survey methods (convenience-based versus systematic), landscape-scale agriculture-related variables, and extent of remnant habitat. Changes in seasonal crops can additionally alter landscape and habitat conditions thereby influencing species occupancy. We investigated how these factors affect modeled occupancy of 56 resident bird species using a landscape-scale multi-season occupancy framework across 24 intensively cultivated and human-dominated districts in Uttar Pradesh state, north India. Convenience-based roadside observations provided considerable differences in occupancy estimates and associations with remnant habitat and intensity of cultivation relative to systematic transect counts, and appeared to bias results to roadside conditions. Modeled occupancy of only open-area species improved with increasing intensity of cultivation, while remnant habitat improved modeled occupancy of scrubland, wetland and woodland species. Strong seasonal differences in occupancy were apparent for most species across all habitat guilds. Further habitat loss will be most detrimental to resident scrubland, wetland and woodland species. Uttar Pradesh’s agricultural landscape has a high conservation value, but will require a landscape-level approach to maintain the observed high species richness. Obtaining ecological information from unexplored landscapes using robust landscape-scale surveys offers substantial advantages to understand factors affecting species occupancy, and is necessary for efficient conservation planning.
The Indian subcontinent has the world's highest cropland cover per unit area with rice (Oryza sativa) being the second-most important crop, and is home to nearly 1,300 species of birds. The significance of rice fields as bird habitat in the region is not well understood and the subject is reviewed using a combination of published and secondary information. Rice fields in the subcontinent are used by at least 351 species, although only 2.7% of birds occurring in the subcontinent breed in rice fields. The spread of rice cultivation and its attendant secondary habitats may have contributed to the increase in range and population of 64 common species but is threatening hundreds of other species, many of conservation concern. Most work in the region has focused on birds as pests of rice. Few studies have been conducted on the habits of birds that use rice fields and fewer still have compared how rice fields and similar natural habitats differ. Although rice harvesting has caused nest mortality for breeding birds, there is no comparable information from natural habitats. The guild structure of birds in rice fields is similar to that overall in the region except for a higher representation of carnivores. Rice fields are used primarily by grassland and wetland species. There are large information gaps that require filling to be able to ascertain the utility or impact of rice fields to bird populations and, thus, many research opportunities.
Agricultural landscapes provide a wide variety of avian habitats that vary seasonally. The effects of seasonal habitat changes on the habits of four large waterbird species in an agriculture-wetland mosaic are investigated in this paper. The habits of Painted Storks (Mycteria leucocephala), Asian Openbills (Anastomus oscitans), Woolly-necked Storks (Ciconia episcopus) and Black-headed Ibis (Threskiornis melanocephalus) were documented over a 15-month period in Etawah and Mainpuri districts, Uttar Pradesh, India. Monthly road transects were undertaken to determine flock sizes, density, and habitat preference of these species. Flock sizes varied significantly with season for Woolly-necked Storks and Black-headed Ibis and with habitat for Painted Storks. Flock size and density were strongly correlated in all four species. Increasing wetland size and extent of wetlands in the landscape affected flock size of Asian Openbills implying that food availability may be the most important factor affecting flocking in this species. Density differed seasonally for Woolly-necked Storks and Black-headed Ibis. Density of all four species did not vary with extent of wetlands in the landscape. Monthly densities of Black-headed Ibis were correlated to that of all the other three species. Habitat use varied widely across species and seasons. Natural wetlands but not rice fields were preferred by all four species in nearly all seasons. Irrigation canals were avoided consistently by the Black-headed Ibis and used to different extents by the other three species. Flooded agriculture fields did not compensate adequately for natural wetlands. Wetlands need to be retained in agricultural landscapes to ensure continued survival of these species.
Grus antigone, una especie de grulla amenazada globalmente, presenta una productividad anual baja y se encuentra principalmente en paisajes dominados por áreas agrícolas. Por lo tanto, la especie es vulnerable a la extinción a causa de disturbios y mortalidad relacionados con los humanos. El incremento en el uso de arrozales por parte de G. antigone como hábitat de anidación ha causado preocupación, ya que la especie estaria siendo forzada a utilizar ambientes de calidad inferior. Para examinar este asunto, en 2000 y 2001 estudié la selección de sitios de anidación y cuantifiqué la supervivencia de los nidos y las parvadas de esta especie en Uttar Pradesh, norte de India. Además, evalué las diferencias entre humedales naturales y arrozales. Las grullas prefirieron los humedales como habitat de anidación a nivel del paisaje y de los territorios individuales. El éxito (tasa de supervivencia diaria) de los nidos ubicados más cerca de las carreteras fue menor, lo que sugiere que la mortalidad relacionada con los humanos jugó un papel. El efecto del hábitat sobre el éxito de los nidos fue equívoco, lo que sugiere que los arrozales per se no son sitios de anidación subóptimos. Este resultado es único para esta área, por lo que es probable que las actitudes favorables de los agricultures aún permitan que las grullas aniden en los arrozales. Las parvadas que eclosionaron más tarde y aquellas que estaban en territorios con menos humedales presentaron una probabilidad de sobrevivir menor. Los cambios en la vegetación y los disturbios relacionados con la cosecha del arroz probablemente causaron una disminución en la supervivencia de las parvadas. Mantener un conjunto de parches, incluyendo humedales poco profundus en paisajes dominados por arroz y asegurar que los agricultores retengan una actitud positiva ante la especie, es crucial para la supervivencia de sus nidos y parvadas.
Breeding density, spacing of nest-sites and breeding performance of Black Storks Ciconia nigra in Dadia-Lefkimi
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Alenxandrou, O., D. E. Bakaloudis, M. A. Papakosta
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Special section editorial: Woollynecked Stork -a species ignored
- K S G Sundar
Sundar, K. S. G. 2020. Special section editorial: Woollynecked Stork -a species ignored. SIS Conservation
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