Nesting site selection of the Asian Openbill (Anastomus oscitans) on isolated island and their movement to nearby foraging areas

Nesting site selection of the Asian Openbill (Anastomus oscitans) on isolated island and their movement to nearby foraging areas | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Nesting site selection of the Asian Openbill (Anastomus oscitans) on isolated island and their movement to nearby foraging areas Badrulhadza Amzah, Rosli Ramli, Noorhidayah Mamat This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5990136/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background This study examines the nesting and foraging ecology of the Asian Openbill ( Anastomus oscitans ) in Perak, Malaysia, focusing on Pulau Bangau and nearby rice fields. Pulau Bangau, located within the Perak River, emerged as an ideal nesting site due to its isolation, availability of large nesting trees such as berembang or Sonneratia caseolaris , and proximity to extensive rice fields serving as primary foraging grounds. Methods Fieldwork conducted from September 2022 to February 2023 documented nesting site preferences and foraging activities through visual observations, photographic documentation, and drone imagery. Results The findings reveal that proximity to water bodies, abundant food sources, and minimal disturbances are critical factors influencing nest site selection, consistent with patterns observed in other regions. Observations in nearby rice fields recorded significant stork activity, emphasizing the importance of agricultural landscapes in supporting the species. Ulu Dedap Blocks B and D were identified as key foraging areas, with the highest stork counts and observation frequencies. The study underscores the interdependence between nesting and foraging habitats, highlighting the energy efficiency and reproductive success associated with close habitat connectivity. However, reliance on agricultural landscapes poses challenges, including habitat degradation and food availability disruptions due to land-use changes. Conclusion These findings have important conservation implications, advocating for the protection of Pulau Bangau and sustainable management of rice fields. Integrating biodiversity-friendly practices in agriculture and preserving mature trees are critical for safeguarding the species' habitats and ensuring its long-term viability in Malaysia. Asian Openbill Nesting site selection Foraging ecology Pulau Bangau Agricultural landscapes Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Background The Asian Openbill ( Anastomus oscitans ), a medium-sized stork species, is widely distributed across South and Southeast Asia (Ali & Ripley 1993; BirdLife 2025), inhabiting diverse wetlands and agricultural landscapes. Its range has expanded into regions such as Peninsular Malaysia and southwestern China in recent years, reflecting its adaptability to various environments (Abidin et al. 2015; Abidin et al. 2017; Liu et al. 2015). The species predominantly forages in crop fields, irrigation canals, and seasonal marshes, making it an important ecological component of wetland and agricultural ecosystems. Despite its growing presence in Malaysia, particularly in northern states such as Perak, research on the nesting site selection and associated ecological preferences of the Asian Openbill in this region remains limited. Existing studies have primarily focused on the species' distribution or general foraging behaviour, while the specific nesting habitat requirements and their relationship with nearby foraging areas, especially in human-altered landscapes like rice fields, are poorly understood. This gap in knowledge poses a challenge for effective conservation and habitat management of the species in Malaysia, where increasing land-use changes and agricultural intensification may impact its nesting and foraging dynamics. To date, no comprehensive research has been conducted specifically on nesting sites selection of Asian Openbills in Malaysia. The aim of this study is to determine the nest site selection of the Asian Openbill in Perak, Malaysia, and to identify foraging areas of this stork species in nearby habitats, particularly in the extensive rice fields. By addressing these gaps, the study seeks to provide critical insights for the conservation of the Asian Openbill in Malaysia and inform sustainable land management practices. Methods Study area The study was conducted at Pulau Bangau (4° 01’ 43.3” N, 100° 59’ 57.9” E), a small island in the Perak River within the Hilir Perak district, and the surrounding rice field areas in Perak Tengah district, Perak, Malaysia. Fieldwork was carried out from September 2022 to February 2023. Pulau Bangau, a known roosting and nesting site for the Asian Openbill ( Anastomus oscitans ), was surveyed along with nearby rice fields, which serve as the species’ primary foraging grounds. Data collection Bird activity and movement observations The nesting and foraging activities of the Asian Openbill were observed through direct visual assessments, complemented by photographic and videographic documentation. High-resolution images and videos were captured using DSLR cameras and smartphones, while a drone equipped with a high-resolution camera provided aerial perspective of the study area, including nesting and foraging sites. Observations were conducted during two key activity periods: morning sessions from 0800 to 1000 hours and afternoon sessions from 1700 to 1900 hours. Nesting site assessment The assessment of nesting sites focused solely on identifying the tree species utilized for nesting. This was recorded through visual inspection and photographic documentation during observations at Pulau Bangau. Foraging activity monitoring Monitoring of foraging activity was conducted in the rice fields surrounding Pulau Bangau, including areas managed by FELCRA Seberang Perak, IADA Seberang Perak, and IADA Kerian. The focus of the observations was on counting the number of individual storks present in the fields. Photographic and videographic documentation was used solely to assist in accurately counting the birds and to confirm the presence of bird activities in the rice fields. No behavioral data or analyses were included in the study. Multiple observation sessions were conducted across the study period to ensure comprehensive data collection on bird numbers. Data analysis The collected data were analyzed descriptively, focusing on the counts of individual birds and flocks observed in the study area. Photographic and videographic documentation was used to validate the bird counts and confirm the presence of bird activity in Pulau Bangau and the surrounding rice fields. The results were presented in terms of flock sizes and the spatial distribution of bird in nesting and foraging areas, as captured through drone imagery and videos. No analysis for bird behaviour or movement patterns was conducted. Results and Discussion Ramachandran and Vijay (1994) mentioned that nesting site selection is an important factor for successful breeding colony for birds. For this study, nesting site selection by the Asian Openbill ( Anastomus oscitans ) is intricately linked with the proximity of water bodies, availability of nesting materials, and reduced predation risks. According to Martin and Ropper (1988), site selection for roosting or breeding is important to protect birds from dangers while Zhao et al. (2020) mentioned that nest site selection is a vital component of bird reproduction success. It is an adaptive behaviour to decrease nest predation risk with avoiding external disturbances. In Perak, Malaysia, Pulau Bangau emerged as an ideal nesting site due to its isolated location within the Perak River, which minimises human disturbances and offers abundant resources. According to Garg (2016), river can minimise the outside disturbance, supplying suitable food source, and nesting materials. Gopi and Pandav (2007) also found that among the principal factors for large congregation of breeding birds is due to the remoteness of the sanctuary area. Similar patterns have been documented in other regions, such as eastern Nepal, where breeding colonies of Lesser adjutants ( Leptoptilos javanicus ) are found across human-dominated landscapes, indicating their adaptability to altered habitats (Katuwal et al. 2022). Studies in Navsari, Gujarat, India, have further highlighted the species' preference for nesting near water bodies and agricultural areas that provide ample foraging opportunities (Bavchandbhai 2022). Pulau Bangau mirrors these conditions, with its proximity to the expansive rice granaries of FELCRA Seberang Perak, IADA Seberang Perak, and IADA Kerian (Fig. 1 ). The availability of large, mature trees, particularly Sonneratia caseolaris (berembang) (Fig. 2 ), serves as crucial nesting structures, similar to the preferences of the Black stork ( Ciconia nigra ), which selects large, old trees near shallow wetlands for nesting (Clancy & Ford 2011). Birds, particularly large tree-nesting waterbirds, prioritize secure and sturdy nest support structures when choosing a nest site (Vergara & Aguirre 2006; Onmus et al. 2012). The island's strategic location within the Perak River offers natural defense mechanisms against predators while providing easy access to nearby rice fields, where mollusks and small aquatic organisms are abundant. This habitat connectivity is essential for nesting success, as it minimizes energy expenditure during the breeding season (Cheng et al. 2023). Furthermore, Cheng et al. (2023) discovered that storks' nest site selection preferences demonstrated varied adaptive techniques in response to human activities and food availability. The proximity of foraging areas to nesting sites is critical for ensuring the reproductive success of stork species. Observations during this study revealed consistent foraging activity by Asian Openbills in the nearby rice fields, with birds returning to Pulau Bangau from the north-western (FELCRA Seberang Perak, Kampung Gajah, Ulu Dedap) and north-eastern (Sungai Manik, Chenderong Balai) directions between 1800 and 1900 hours (Figs. 3 and 4 ). Asian Openbills primarily forage in inland wetlands and agricultural fields, feeding on mollusks, insects, and other small aquatic organisms (Pramanik et al. 2013). This reliance on rice fields underscores the importance of agricultural landscapes in supporting the species. Studies on the White Stork ( Ciconia ciconia ) have shown that foraging within close proximity to nesting colonies enhances energy efficiency and chick provisioning (Tortosa et al. 2009). Similarly, Wood Storks ( Mycteria americana ) have been observed selecting foraging sites within 20 km of nesting colonies, prioritizing habitats such as swamps and marshes (Herring et al. 2015). In this study, the integration of rice fields into the birds’ foraging strategy mirrors these global patterns, emphasizing the significance of maintaining nearby foraging habitats for the Asian Openbill's reproductive success. Figures 5 a, b, and c illustrate the foraging activity of the species in these rice fields, highlighting their role in sustaining the growing population on Pulau Bangau. Tamang et al. (2024) have noted a number of Asian openbill colonies in agricultural landscapes and human-populated places. According to their study, Asian openbill storks may be more dependent on agricultural landscapes than on other types of habitat since these areas are irrigated and offer year-round food (Sundar et al. 2016; Koju et al. 2019). Table 1 summarizes the observation records of Asian Openbills in several locations during the study period. The total number of storks observed was 2,266, with Ulu Dedap Block B recording the highest count at 889 storks, followed by Ulu Dedap Block D with 741 storks. In contrast, the lowest total count was recorded at Sungai Manik, Teluk Intan, with only 23 storks. On average, Ulu Dedap Block B also had the highest number of storks per observation (148.2), indicating a consistently high presence of storks during the observation periods, while Sungai Manik had the lowest average at just 4.6 storks. Interestingly, FELCRA Seberang Perak Block 9 recorded a high average of 116 storks, but this result is based on a single observation, which may not accurately represent the overall stork activity in that area. Table 1 Observation records of Asian openbill in Perak during the study period. Location Total number of Asian openbill stork for all observation times Average number of Asian openbill stork Number of Observation FELCRA Seberang Perak (Block 10) 102 44.7 3 FELCRA Seberang Perak (Block 6) 253 50.6 5 FELCRA Seberang Perak (Block 8) 142 28.4 5 FELCRA Seberang Perak (Block 9) 116 116 1 Sungai Manik, Teluk Intan 23 4.6 5 Ulu Dedap Block B 889 148.2 6 Ulu Dedap Block D 741 61.6 12 Overall Total Number 2266 The number of observations varied significantly between locations, with Ulu Dedap Block D having the highest frequency of observations (12), suggesting consistent monitoring efforts or better accessibility. On the other hand, FELCRA Seberang Perak Block 9 was observed only once, potentially limiting the reliability of the data. The data highlights Ulu Dedap as a critical habitat for Asian Openbills, likely due to favorable environmental conditions such as abundant prey and minimal disturbance. Conversely, the low numbers recorded in Sungai Manik suggest that this area may be less suitable as a habitat for these birds or that it is on the periphery of their typical range. These findings have important conservation implications. The high concentration of storks in Ulu Dedap underscores the importance of preserving and managing this habitat. At the same time, areas with lower stork activity, such as Sungai Manik, may benefit from further studies to identify factors limiting their suitability and explore potential habitat restoration measures. Increasing observation frequency at under-monitored locations, such as FELCRA Seberang Perak Block 9, would also improve data accuracy. Overall, the study highlights the variability in stork presence across different sites and provides insights into their habitat preferences, emphasizing the need for targeted conservation efforts. The selection of Pulau Bangau as a nesting site by Asian Openbills is a testament to the species' ecological adaptability and resilience. Its location within the Perak River provides a secure, undisturbed environment with abundant nesting materials and access to foraging areas. Similar to observations in Nepal and China, the presence of large trees and proximity to wetlands or agricultural fields are key factors influencing site selection (Koju et al. 2019; Zhang et al. 2022). The dependence on rice fields as primary foraging habitats highlights the importance of agricultural landscapes in the species' survival. However, this reliance also presents challenges, as land-use changes, pesticide applications, and wetland drainage can disrupt food availability and habitat quality. Comparative studies with other stork species, such as the Black Stork ( Ciconia nigra ) and White Stork ( Ciconia ciconia ), further illustrate the critical role of foraging site proximity in reducing energy expenditure and enhancing breeding success (Tortosa et al 2009; Clancy and Ford 2011). The establishment of a resident population on Pulau Bangau marks a significant milestone for the Asian Openbill in Malaysia, transitioning from vagrant to resident status. Conservation efforts should prioritize the protection of Pulau Bangau and the sustainable management of nearby rice fields to ensure the long-term viability of this population. Initiatives such as habitat restoration, preservation of large trees, and the promotion of eco-friendly agricultural practices are essential for safeguarding the species' nesting and foraging habitats. In conclusion, understanding the nesting and foraging ecology of the Asian Openbill provides critical insights into its habitat requirements. Protecting wetlands, maintaining mature trees, and integrating biodiversity-friendly practices into agricultural landscapes will be vital for conserving this species and supporting its continued expansion in Malaysia. Declarations Ethical statements This research involved the observation of storks (family Ciconiidae) in their natural habitat. No invasive procedures were performed, and all observations adhered to ethical guideline for wildlife research. Competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Informed consent Informed consent was not required as this study did not involve human participants or interventions. Funding This research and manuscript preparation received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. Author Contribution B.A. carried out the field observation, obtained data and wrote the main manuscript text. R.R. and N.M. supervised the works, developed the idea and concept as well as reviewed and edited the manuscript. Acknowledgements Authors are grateful to Mr. Muhammad Sahril Mustafa (River Cruise, Teluk Intan), Mr. Faizuin Abd. Hamid (who assist in taking photos and videos using drone), Mr. Roslee Halip and Mr. Muhammad Danial Danish Umar (for their assistance in data collections). The authors also would like to express their gratitude to the Institute of Biological Sciences, Universiti Malaya and Malaysia Agricultural Research and Development Institute (MARDI) for the support. References Abidin MKZ, Nor SM, Taib FSM. Distribution pattern of Asian openbill ( Anastomus oscitans ) in Peninsular Malaysia. Journal of Wildlife and Parks. 2015;30:75–80. Abidin MKZ, Taib FSM, Nor SM. Distribution and habitat selection of the Asian Openbill ( Anastomus oscitans ) in Peninsular Malaysia. Malayan Nature Journal. 2017;69(3):169–181. Ali S, Ripley DS. Handbook of the Birds of India and Pakistan (v. 6). OUP India. 2003. Bavchandbhai VH. Distribution and nesting habitat of Asian openbill stork ( Anastomus oscitans ) in Navsari, Gujarat, India. International Journal of Scientific Research. 2022;11(6):46–48. BirdLife International (2025) Species factsheet: Asian Openbill Anastomus oscitans . Downloaded from https://datazone.birdlife.org/species/factsheet/asian-openbill-anastomus-oscitans on 02/01/2025. Cheng L, Zhou L, Yu C, Wei Z, Li C. Flexible nest site selection of the endangered oriental storks ( Ciconia boyciana ): Trade-off from adaptive strategies. Avian Research. 2023;14:100088. Clancy, GP, Ford HA. Nest site selection and nesting behaviour of the Black-necked stork Ephippiorhynchus asiaticus australis in northern New South Wales. Corella. 2011;35(4):95–100. Garg A. Nest-plant correlation and predator preclusion in Asian openbill storks ( Anastomus oscitans ): a case study from Nawabgunj bird sanctuary, India. India Forester. 2016;142(2):179–186. Gopi GV, Pandav B. Observations on breeding biology of three storks species in Bhitarkanika mangroves, India. Indian Birds. 2007;3(2):45–50. Herring G, Herring H, Gawlik DE. Social cues and environmental conditions influence foraging flight distances of breeding Wood storks ( Mycteria americana ). Waterbirds. 2015;38:30–39. Katuwal HB, Sundar KSG, Zhang M, Rimal B, Baral HS, Sharma HP, Ghimire P Hughes AC, Quan, R.C. Factors affecting the breeding ecology of the globally threatened lesser adjutant Leptoptilos javanicus in agricultural landscapes of Nepal. Avian Conservation and Ecology. 2022;17(2):15. Koju R, Maharjan B, Gosai KR, Kittur S, Sundar KSG. Ciconiiformes nesting on trees in cereal-dominated farmlands: Importance of scattered trees for heronries in lowland Nepal. Waterbirds. 2019;42(4):355–453. Liu Q, Buzzard P, Luo X. Rapid range expansion of Asian Openbill Anastomus oscitans in China. Forktail. 2015;31:141–143. Martin TE, Roper JJ. Nest predation and nest-site selection of a western population of the Hermit Thrush. Condor. 1988;90:51–57. Onmus O, Agao glu Y, Gül O. Environmental factors affecting nest-site selection and breeding success of the White Stork ( Ciconia ciconia ) in western Turkey. Wilson J. Ornithol. 2012;124: 354–361. Pramanik AK, Santra KB, Manna CK. Nest site characteristics and nest diversity of Ciconiidae ( Anastomus oscitans ), Phalacrocoracidae ( Phalacrocorax niger ) and Ardeidae ( Nycticorax nycticorax , Bubulcus ibis ) in the Kulik bird sanctuary, Raiganj, West Bengal, India. Journal of Biodiversity and Ecological Sciences. 2013;3(4):169–176. Ramachandran NK, Vijayan VS. Distribution and general ecology of the Sarus crane ( Grus antigore ) in Keoladeo National Park, Rajashtan. Journal of The Bombay Natural History Society. 1994;91:427–441. Sundar KSG, Maharjan B, Koju R, Kittur S, Gosai KR. Factors affecting provisioning times of two stork species in lowland Nepal. Waterbirds. 2016;39(4):365–374. Tamang G, Katuwal HB, Subba A, Singh NB. Breeding ecology of the Asian openbill in eastern Nepal: Larger trees support higher fledgling success. Ecology and Evoloution. 2024;14:e11504. Tortosa FS, Cabalerro JM, Reyes-Lopes J. Effect of rubbish dumps on breeding success in the white stork in Southern Spain. Waterbirds. 2009;25:39–43. Vergara P, Aguirre IJ. Age and breeding success related to nest position in a White Stork Ciconia ciconia colony. Acta Oecol. 2006;30:414–418. Zhang M, Wang L, Li J, Wang Q, Luo A. Hail-induced mortality of Asian Openbill ( Anastomus oscitans ) in Southern Tropical China. Ecology and Evolution. 2022;12(6): e8983. Zhao JM, Yang C, Lou YQ, Shi M, Fang Y, Sun YH. Nesting season, nest age, and disturbance, but not habitat characteristics, affect nest survival of Chinese Grouse. Curr. Zool. 2020;66: 29–37. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5990136","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":414613572,"identity":"daf09db2-8194-4715-adb4-6de7d452cde3","order_by":0,"name":"Badrulhadza Amzah","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1UlEQVRIiWNgGAWjYBACAwkGBiCyAbMPkKIljXQth8Fs4hxmLt388OaPmvPR/LMPbzzA8MsmsUHsDH69lnOOGVtIHLudO+NcWsEBxr60xAbpHPxaDG4kmEkYsN3ObTjDY3CAseewMQNhLenfJBL+ncudT4KWHDOJg20HcjeAtDD8OCxHUIvljJxiy8a+5NyNZ9gKDiQ2pMmxSacV4NViLpG+8eaPb3a5884wb/7w4Y8ND7908ga8WlBBYhsDAxsDB5ERBAF/QAT7A1K0jIJRMApGwfAHAPS5S2OzUUecAAAAAElFTkSuQmCC","orcid":"","institution":"Universiti Malaya","correspondingAuthor":true,"prefix":"","firstName":"Badrulhadza","middleName":"","lastName":"Amzah","suffix":""},{"id":414613573,"identity":"e234688b-3f1c-4ffb-84e2-0f5225816aaf","order_by":1,"name":"Rosli Ramli","email":"","orcid":"","institution":"Universiti Malaya","correspondingAuthor":false,"prefix":"","firstName":"Rosli","middleName":"","lastName":"Ramli","suffix":""},{"id":414613574,"identity":"3383ddda-0b41-4dc7-bc8d-a3f922731323","order_by":2,"name":"Noorhidayah Mamat","email":"","orcid":"","institution":"Universiti Malaya","correspondingAuthor":false,"prefix":"","firstName":"Noorhidayah","middleName":"","lastName":"Mamat","suffix":""}],"badges":[],"createdAt":"2025-02-09 02:08:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5990136/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5990136/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":76291235,"identity":"cc03d406-3606-4c43-a178-17b59d5c919e","added_by":"auto","created_at":"2025-02-14 12:11:27","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":281660,"visible":true,"origin":"","legend":"\u003cp\u003eLocation of Pulau Bangau and nearby rice granary areas.\u003c/p\u003e","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5990136/v1/d2e489e6f36e9682d36976dd.jpg"},{"id":76291239,"identity":"30051607-23de-4ce0-9ee8-4128a5a231d5","added_by":"auto","created_at":"2025-02-14 12:11:27","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":9101402,"visible":true,"origin":"","legend":"\u003cp\u003eThe Asian Openbills make their nests on berembang trees.\u003c/p\u003e","description":"","filename":"Fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5990136/v1/0711e29cb3ef36fd564782fc.jpg"},{"id":76291452,"identity":"bf819841-d386-46a7-a38e-a99ed69c5bcf","added_by":"auto","created_at":"2025-02-14 12:19:27","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":6628027,"visible":true,"origin":"","legend":"\u003cp\u003eFlock of Asian Openbills flew back from the north-western side of Pulau Bangau\u003c/p\u003e","description":"","filename":"Fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5990136/v1/b35ef364fa3fe5867d50814f.jpg"},{"id":76291237,"identity":"a4ea619a-fe36-438e-b8ed-a826d73c2564","added_by":"auto","created_at":"2025-02-14 12:11:27","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":262100,"visible":true,"origin":"","legend":"\u003cp\u003eFlight direction of the Asian openbill storks to Pulau Bangau from the foraging sites.\u003c/p\u003e","description":"","filename":"Fig4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5990136/v1/5212b9c5b307450f8ec78a74.jpg"},{"id":76291244,"identity":"2ef8e5f2-0684-4a49-9ee4-6a77ec5e2b73","added_by":"auto","created_at":"2025-02-14 12:11:28","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":79827,"visible":true,"origin":"","legend":"\u003cp\u003eForaging activity of Asian Openbills in the field. (a) Flock of Asian Openbills at FELCRA Seberang Perak rice field area. Observation on 16 October 2022. (b) Flock of Asian Openbills at Ulu Dedap (Block D) rice field area (IADA Seberang Perak). Observation on 29 October 2022. (c) Flock of Asian Openbills at Ulu Dedap (Block B) rice field area (IADA Seberang Perak). Observation on 1 February 2023.\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5990136/v1/e0cbf15371ca28c156ed7a18.jpg"},{"id":77077021,"identity":"ff8a00e4-9160-474b-8dd3-40235c1689b6","added_by":"auto","created_at":"2025-02-25 01:01:18","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":16868282,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5990136/v1/1be8c5bd-90e9-48db-9e65-58a045758d71.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Nesting site selection of the Asian Openbill (Anastomus oscitans) on isolated island and their movement to nearby foraging areas","fulltext":[{"header":"Background","content":"\u003cp\u003eThe Asian Openbill (\u003cem\u003eAnastomus oscitans\u003c/em\u003e), a medium-sized stork species, is widely distributed across South and Southeast Asia (Ali \u0026amp; Ripley 1993; BirdLife 2025), inhabiting diverse wetlands and agricultural landscapes. Its range has expanded into regions such as Peninsular Malaysia and southwestern China in recent years, reflecting its adaptability to various environments (Abidin et al. 2015; Abidin et al. 2017; Liu et al. 2015). The species predominantly forages in crop fields, irrigation canals, and seasonal marshes, making it an important ecological component of wetland and agricultural ecosystems.\u003c/p\u003e \u003cp\u003eDespite its growing presence in Malaysia, particularly in northern states such as Perak, research on the nesting site selection and associated ecological preferences of the Asian Openbill in this region remains limited. Existing studies have primarily focused on the species' distribution or general foraging behaviour, while the specific nesting habitat requirements and their relationship with nearby foraging areas, especially in human-altered landscapes like rice fields, are poorly understood. This gap in knowledge poses a challenge for effective conservation and habitat management of the species in Malaysia, where increasing land-use changes and agricultural intensification may impact its nesting and foraging dynamics.\u003c/p\u003e \u003cp\u003eTo date, no comprehensive research has been conducted specifically on nesting sites selection of Asian Openbills in Malaysia. The aim of this study is to determine the nest site selection of the Asian Openbill in Perak, Malaysia, and to identify foraging areas of this stork species in nearby habitats, particularly in the extensive rice fields. By addressing these gaps, the study seeks to provide critical insights for the conservation of the Asian Openbill in Malaysia and inform sustainable land management practices.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy area\u003c/h2\u003e \u003cp\u003eThe study was conducted at Pulau Bangau (4\u0026deg; 01\u0026rsquo; 43.3\u0026rdquo; N, 100\u0026deg; 59\u0026rsquo; 57.9\u0026rdquo; E), a small island in the Perak River within the Hilir Perak district, and the surrounding rice field areas in Perak Tengah district, Perak, Malaysia. Fieldwork was carried out from September 2022 to February 2023. Pulau Bangau, a known roosting and nesting site for the Asian Openbill (\u003cem\u003eAnastomus oscitans\u003c/em\u003e), was surveyed along with nearby rice fields, which serve as the species\u0026rsquo; primary foraging grounds.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eData collection\u003c/h3\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eBird activity and movement observations\u003c/h2\u003e \u003cp\u003eThe nesting and foraging activities of the Asian Openbill were observed through direct visual assessments, complemented by photographic and videographic documentation. High-resolution images and videos were captured using DSLR cameras and smartphones, while a drone equipped with a high-resolution camera provided aerial perspective of the study area, including nesting and foraging sites. Observations were conducted during two key activity periods: morning sessions from 0800 to 1000 hours and afternoon sessions from 1700 to 1900 hours.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eNesting site assessment\u003c/h3\u003e\n\u003cp\u003eThe assessment of nesting sites focused solely on identifying the tree species utilized for nesting. This was recorded through visual inspection and photographic documentation during observations at Pulau Bangau.\u003c/p\u003e\n\u003ch3\u003eForaging activity monitoring\u003c/h3\u003e\n\u003cp\u003eMonitoring of foraging activity was conducted in the rice fields surrounding Pulau Bangau, including areas managed by FELCRA Seberang Perak, IADA Seberang Perak, and IADA Kerian. The focus of the observations was on counting the number of individual storks present in the fields. Photographic and videographic documentation was used solely to assist in accurately counting the birds and to confirm the presence of bird activities in the rice fields. No behavioral data or analyses were included in the study. Multiple observation sessions were conducted across the study period to ensure comprehensive data collection on bird numbers.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eData analysis\u003c/h2\u003e \u003cp\u003eThe collected data were analyzed descriptively, focusing on the counts of individual birds and flocks observed in the study area. Photographic and videographic documentation was used to validate the bird counts and confirm the presence of bird activity in Pulau Bangau and the surrounding rice fields. The results were presented in terms of flock sizes and the spatial distribution of bird in nesting and foraging areas, as captured through drone imagery and videos. No analysis for bird behaviour or movement patterns was conducted.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003eRamachandran and Vijay (1994) mentioned that nesting site selection is an important factor for successful breeding colony for birds. For this study, nesting site selection by the Asian Openbill (\u003cem\u003eAnastomus oscitans\u003c/em\u003e) is intricately linked with the proximity of water bodies, availability of nesting materials, and reduced predation risks. According to Martin and Ropper (1988), site selection for roosting or breeding is important to protect birds from dangers while Zhao et al. (2020) mentioned that nest site selection is a vital component of bird reproduction success. It is an adaptive behaviour to decrease nest predation risk with avoiding external disturbances.\u003c/p\u003e \u003cp\u003eIn Perak, Malaysia, Pulau Bangau emerged as an ideal nesting site due to its isolated location within the Perak River, which minimises human disturbances and offers abundant resources. According to Garg (2016), river can minimise the outside disturbance, supplying suitable food source, and nesting materials. Gopi and Pandav (2007) also found that among the principal factors for large congregation of breeding birds is due to the remoteness of the sanctuary area. Similar patterns have been documented in other regions, such as eastern Nepal, where breeding colonies of Lesser adjutants (\u003cem\u003eLeptoptilos javanicus\u003c/em\u003e) are found across human-dominated landscapes, indicating their adaptability to altered habitats (Katuwal et al. 2022).\u003c/p\u003e \u003cp\u003eStudies in Navsari, Gujarat, India, have further highlighted the species' preference for nesting near water bodies and agricultural areas that provide ample foraging opportunities (Bavchandbhai 2022). Pulau Bangau mirrors these conditions, with its proximity to the expansive rice granaries of FELCRA Seberang Perak, IADA Seberang Perak, and IADA Kerian (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The availability of large, mature trees, particularly \u003cem\u003eSonneratia caseolaris\u003c/em\u003e (berembang) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), serves as crucial nesting structures, similar to the preferences of the Black stork (\u003cem\u003eCiconia nigra\u003c/em\u003e), which selects large, old trees near shallow wetlands for nesting (Clancy \u0026amp; Ford 2011). Birds, particularly large tree-nesting waterbirds, prioritize secure and sturdy nest support structures when choosing a nest site (Vergara \u0026amp; Aguirre 2006; Onmus et al. 2012).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe island's strategic location within the Perak River offers natural defense mechanisms against predators while providing easy access to nearby rice fields, where mollusks and small aquatic organisms are abundant. This habitat connectivity is essential for nesting success, as it minimizes energy expenditure during the breeding season (Cheng et al. 2023). Furthermore, Cheng et al. (2023) discovered that storks' nest site selection preferences demonstrated varied adaptive techniques in response to human activities and food availability.\u003c/p\u003e \u003cp\u003eThe proximity of foraging areas to nesting sites is critical for ensuring the reproductive success of stork species. Observations during this study revealed consistent foraging activity by Asian Openbills in the nearby rice fields, with birds returning to Pulau Bangau from the north-western (FELCRA Seberang Perak, Kampung Gajah, Ulu Dedap) and north-eastern (Sungai Manik, Chenderong Balai) directions between 1800 and 1900 hours (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAsian Openbills primarily forage in inland wetlands and agricultural fields, feeding on mollusks, insects, and other small aquatic organisms (Pramanik et al. 2013). This reliance on rice fields underscores the importance of agricultural landscapes in supporting the species. Studies on the White Stork (\u003cem\u003eCiconia ciconia\u003c/em\u003e) have shown that foraging within close proximity to nesting colonies enhances energy efficiency and chick provisioning (Tortosa et al. 2009). Similarly, Wood Storks (\u003cem\u003eMycteria americana\u003c/em\u003e) have been observed selecting foraging sites within 20 km of nesting colonies, prioritizing habitats such as swamps and marshes (Herring et al. 2015).\u003c/p\u003e \u003cp\u003eIn this study, the integration of rice fields into the birds\u0026rsquo; foraging strategy mirrors these global patterns, emphasizing the significance of maintaining nearby foraging habitats for the Asian Openbill's reproductive success. Figures\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea, b, and c illustrate the foraging activity of the species in these rice fields, highlighting their role in sustaining the growing population on Pulau Bangau. Tamang et al. (2024) have noted a number of Asian openbill colonies in agricultural landscapes and human-populated places. According to their study, Asian openbill storks may be more dependent on agricultural landscapes than on other types of habitat since these areas are irrigated and offer year-round food (Sundar et al. 2016; Koju et al. 2019).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the observation records of Asian Openbills in several locations during the study period. The total number of storks observed was 2,266, with Ulu Dedap Block B recording the highest count at 889 storks, followed by Ulu Dedap Block D with 741 storks. In contrast, the lowest total count was recorded at Sungai Manik, Teluk Intan, with only 23 storks. On average, Ulu Dedap Block B also had the highest number of storks per observation (148.2), indicating a consistently high presence of storks during the observation periods, while Sungai Manik had the lowest average at just 4.6 storks. Interestingly, FELCRA Seberang Perak Block 9 recorded a high average of 116 storks, but this result is based on a single observation, which may not accurately represent the overall stork activity in that area.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eObservation records of Asian openbill in Perak during the study period.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal number of Asian openbill stork for all observation times\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAverage number of Asian openbill stork\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNumber of Observation\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFELCRA Seberang Perak (Block 10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e102\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e44.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFELCRA Seberang Perak (Block 6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e253\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFELCRA Seberang Perak (Block 8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e142\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFELCRA Seberang Perak (Block 9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e116\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e116\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSungai Manik, Teluk Intan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUlu Dedap Block B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e889\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e148.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUlu Dedap Block D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e741\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e61.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOverall Total Number\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e2266\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe number of observations varied significantly between locations, with Ulu Dedap Block D having the highest frequency of observations (12), suggesting consistent monitoring efforts or better accessibility. On the other hand, FELCRA Seberang Perak Block 9 was observed only once, potentially limiting the reliability of the data. The data highlights Ulu Dedap as a critical habitat for Asian Openbills, likely due to favorable environmental conditions such as abundant prey and minimal disturbance. Conversely, the low numbers recorded in Sungai Manik suggest that this area may be less suitable as a habitat for these birds or that it is on the periphery of their typical range.\u003c/p\u003e \u003cp\u003eThese findings have important conservation implications. The high concentration of storks in Ulu Dedap underscores the importance of preserving and managing this habitat. At the same time, areas with lower stork activity, such as Sungai Manik, may benefit from further studies to identify factors limiting their suitability and explore potential habitat restoration measures. Increasing observation frequency at under-monitored locations, such as FELCRA Seberang Perak Block 9, would also improve data accuracy. Overall, the study highlights the variability in stork presence across different sites and provides insights into their habitat preferences, emphasizing the need for targeted conservation efforts.\u003c/p\u003e \u003cp\u003eThe selection of Pulau Bangau as a nesting site by Asian Openbills is a testament to the species' ecological adaptability and resilience. Its location within the Perak River provides a secure, undisturbed environment with abundant nesting materials and access to foraging areas. Similar to observations in Nepal and China, the presence of large trees and proximity to wetlands or agricultural fields are key factors influencing site selection (Koju et al. 2019; Zhang et al. 2022).\u003c/p\u003e \u003cp\u003eThe dependence on rice fields as primary foraging habitats highlights the importance of agricultural landscapes in the species' survival. However, this reliance also presents challenges, as land-use changes, pesticide applications, and wetland drainage can disrupt food availability and habitat quality. Comparative studies with other stork species, such as the Black Stork (\u003cem\u003eCiconia nigra\u003c/em\u003e) and White Stork (\u003cem\u003eCiconia ciconia\u003c/em\u003e), further illustrate the critical role of foraging site proximity in reducing energy expenditure and enhancing breeding success (Tortosa et al 2009; Clancy and Ford 2011).\u003c/p\u003e \u003cp\u003eThe establishment of a resident population on Pulau Bangau marks a significant milestone for the Asian Openbill in Malaysia, transitioning from vagrant to resident status. Conservation efforts should prioritize the protection of Pulau Bangau and the sustainable management of nearby rice fields to ensure the long-term viability of this population. Initiatives such as habitat restoration, preservation of large trees, and the promotion of eco-friendly agricultural practices are essential for safeguarding the species' nesting and foraging habitats.\u003c/p\u003e \u003cp\u003eIn conclusion, understanding the nesting and foraging ecology of the Asian Openbill provides critical insights into its habitat requirements. Protecting wetlands, maintaining mature trees, and integrating biodiversity-friendly practices into agricultural landscapes will be vital for conserving this species and supporting its continued expansion in Malaysia.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003cstrong\u003eEthical statements\u003c/strong\u003e \u003cp\u003eThis research involved the observation of storks (family Ciconiidae) in their natural habitat. No invasive procedures were performed, and all observations adhered to ethical guideline for wildlife research.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCompeting interest\u003c/strong\u003e \u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eInformed consent\u003c/strong\u003e \u003cp\u003eInformed consent was not required as this study did not involve human participants or interventions.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis research and manuscript preparation received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eB.A. carried out the field observation, obtained data and wrote the main manuscript text. R.R. and N.M. supervised the works, developed the idea and concept as well as reviewed and edited the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eAuthors are grateful to Mr. Muhammad Sahril Mustafa (River Cruise, Teluk Intan), Mr. Faizuin Abd. Hamid (who assist in taking photos and videos using drone), Mr. Roslee Halip and Mr. Muhammad Danial Danish Umar (for their assistance in data collections). The authors also would like to express their gratitude to the Institute of Biological Sciences, Universiti Malaya and Malaysia Agricultural Research and Development Institute (MARDI) for the support.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAbidin MKZ, Nor SM, Taib FSM. Distribution pattern of Asian openbill (\u003cem\u003eAnastomus oscitans\u003c/em\u003e) in Peninsular Malaysia. Journal of Wildlife and Parks. 2015;30:75\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbidin MKZ, Taib FSM, Nor SM. Distribution and habitat selection of the Asian Openbill (\u003cem\u003eAnastomus oscitans\u003c/em\u003e) in Peninsular Malaysia. Malayan Nature Journal. 2017;69(3):169\u0026ndash;181.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAli S, Ripley DS. Handbook of the Birds of India and Pakistan (v. 6). OUP India. 2003.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBavchandbhai VH. Distribution and nesting habitat of Asian openbill stork (\u003cem\u003eAnastomus oscitans\u003c/em\u003e) in Navsari, Gujarat, India. International Journal of Scientific Research. 2022;11(6):46\u0026ndash;48.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBirdLife International (2025) Species factsheet: Asian Openbill \u003cem\u003eAnastomus oscitans\u003c/em\u003e. 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India Forester. 2016;142(2):179\u0026ndash;186.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGopi GV, Pandav B. Observations on breeding biology of three storks species in Bhitarkanika mangroves, India. Indian Birds. 2007;3(2):45\u0026ndash;50.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHerring G, Herring H, Gawlik DE. Social cues and environmental conditions influence foraging flight distances of breeding Wood storks (\u003cem\u003eMycteria americana\u003c/em\u003e). Waterbirds. 2015;38:30\u0026ndash;39.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKatuwal HB, Sundar KSG, Zhang M, Rimal B, Baral HS, Sharma HP, Ghimire P Hughes AC, Quan, R.C. Factors affecting the breeding ecology of the globally threatened lesser adjutant \u003cem\u003eLeptoptilos javanicus\u003c/em\u003e in agricultural landscapes of Nepal. 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Zool. 2020;66: 29\u0026ndash;37.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Asian Openbill, Nesting site selection, Foraging ecology, Pulau Bangau, Agricultural landscapes","lastPublishedDoi":"10.21203/rs.3.rs-5990136/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5990136/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThis study examines the nesting and foraging ecology of the Asian Openbill (\u003cem\u003eAnastomus oscitans\u003c/em\u003e) in Perak, Malaysia, focusing on Pulau Bangau and nearby rice fields. Pulau Bangau, located within the Perak River, emerged as an ideal nesting site due to its isolation, availability of large nesting trees such as berembang or \u003cem\u003eSonneratia caseolaris\u003c/em\u003e, and proximity to extensive rice fields serving as primary foraging grounds.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eFieldwork conducted from September 2022 to February 2023 documented nesting site preferences and foraging activities through visual observations, photographic documentation, and drone imagery.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe findings reveal that proximity to water bodies, abundant food sources, and minimal disturbances are critical factors influencing nest site selection, consistent with patterns observed in other regions. Observations in nearby rice fields recorded significant stork activity, emphasizing the importance of agricultural landscapes in supporting the species. Ulu Dedap Blocks B and D were identified as key foraging areas, with the highest stork counts and observation frequencies. The study underscores the interdependence between nesting and foraging habitats, highlighting the energy efficiency and reproductive success associated with close habitat connectivity. However, reliance on agricultural landscapes poses challenges, including habitat degradation and food availability disruptions due to land-use changes.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThese findings have important conservation implications, advocating for the protection of Pulau Bangau and sustainable management of rice fields. Integrating biodiversity-friendly practices in agriculture and preserving mature trees are critical for safeguarding the species' habitats and ensuring its long-term viability in Malaysia.\u003c/p\u003e","manuscriptTitle":"Nesting site selection of the Asian Openbill (Anastomus oscitans) on isolated island and their movement to nearby foraging areas","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-02-14 12:11:21","doi":"10.21203/rs.3.rs-5990136/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"1be0fa98-c226-4cb1-94a9-b5bf7f68dd81","owner":[],"postedDate":"February 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-02-25T00:53:06+00:00","versionOfRecord":[],"versionCreatedAt":"2025-02-14 12:11:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5990136","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5990136","identity":"rs-5990136","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}