“…Throughout our study, we see a steady decline in winter reporting rates for this species (Figure 6). This trend is consistent with other long-term studies of roost counts of harriers in India (Ganesh and Prashanth 2018). Figure 6. Monthly trends in reporting rates of the Western Marsh Harrier Circus aeruginosus throughout the study period, with every four years grouped together for clearer visualisation.…”
Section: Resultssupporting
confidence: 92%
“…Throughout our study, we see a steady decline in winter reporting rates for this species (Figure 6). This trend is consistent with other long-term studies of roost counts of harriers in India (Ganesh and Prashanth 2018).…”
Section: Studying Seasonal Trends In Bird Populationssupporting
Summary
Open natural ecosystems (ONEs), such as tropical grasslands, are among the most threatened habitats on Earth today. The long-term monitoring of ONEs is an important research domain that is essential for understanding anthropogenic impacts and facilitating conservation action. Using a simple day-listing method over a 13-year period, we studied species trends in a central Indian grassland–agriculture mosaic experiencing several land-use changes. Our results indicate that some grassland species (such as the Great Indian Bustard Ardeotis nigriceps) showed steep declines during the study period, while other generalist species (such as the Indian Peafowl Pavo cristatus) showed an increasing trend. Daily listing also revealed distinct seasonal patterns, and we discuss the Great Indian Bustard and Western Marsh Harrier Circus aeruginosus as examples. Our study highlights the utility of consistent checklist surveys to monitor population trends of bird communities within a changing landscape.
“…Throughout our study, we see a steady decline in winter reporting rates for this species (Figure 6). This trend is consistent with other long-term studies of roost counts of harriers in India (Ganesh and Prashanth 2018). Figure 6. Monthly trends in reporting rates of the Western Marsh Harrier Circus aeruginosus throughout the study period, with every four years grouped together for clearer visualisation.…”
Section: Resultssupporting
confidence: 92%
“…Throughout our study, we see a steady decline in winter reporting rates for this species (Figure 6). This trend is consistent with other long-term studies of roost counts of harriers in India (Ganesh and Prashanth 2018).…”
Section: Studying Seasonal Trends In Bird Populationssupporting
Summary
Open natural ecosystems (ONEs), such as tropical grasslands, are among the most threatened habitats on Earth today. The long-term monitoring of ONEs is an important research domain that is essential for understanding anthropogenic impacts and facilitating conservation action. Using a simple day-listing method over a 13-year period, we studied species trends in a central Indian grassland–agriculture mosaic experiencing several land-use changes. Our results indicate that some grassland species (such as the Great Indian Bustard Ardeotis nigriceps) showed steep declines during the study period, while other generalist species (such as the Indian Peafowl Pavo cristatus) showed an increasing trend. Daily listing also revealed distinct seasonal patterns, and we discuss the Great Indian Bustard and Western Marsh Harrier Circus aeruginosus as examples. Our study highlights the utility of consistent checklist surveys to monitor population trends of bird communities within a changing landscape.
“…In India, many of the major harrier roosting sites are located within protected areas (Ganesh & Prashanth 2018). Thus, the accessibility to these sites for collecting pellets rest exclusively with Government authorities and researchers with specific permits.…”
Section: Discussionmentioning
confidence: 99%
“…Pellets were collected between September–March during the years' 2015–2017. Prior to pellet collection, roost counts were done in the evenings following the method used by Ganesh & Prashanth (2018), and only pellets which were collected from exclusive Montagu's Harrier roosts were analysed. Pellet collection was done only once per roosting site each season to avoid pseudo-sampling of pellets from the same individuals.…”
Section: Methodsmentioning
confidence: 99%
“…Populations of Montagu's Harriers have been on the decline in India since the last three decades (Ganesh & Prashanth 2018, SoIB 2020, Saravanan et al 2021). Previous studies from the region (Clarke 1996a, Verma 2005) suggest that they mainly feed on orthopterans along with a few rodents, reptiles and other insect species.…”
Studies on the diet composition of bird species provide valuable insights on their habitat use, trophic interactions and prey selection. Prey abundance can drive movements of raptors in their wintering grounds. But such links have been difficult to establish due to the lack of dietary information for most raptor species. Estimating the wintering diet of raptors is a challenge that requires extensive fieldwork across a large geographical area which is often not possible. The methods used in breeding sites such as nest observations are not available in the non-breeding regions.Recently, several studies have demonstrated the use of web-sourced photographs as a tool for understanding the diet of raptors and also the need for combining multiple approaches to get a comprehensive overview of diet. In this study, we use a novel approach by using web-sourced photographs and pellets to estimate the variations in the diet of Montagu's Harrier Circus pygargus, a species in decline, across its wintering range in India. A total of 232 photographs and 391 pellets collected across western India, Deccan and south India during autumn, winter and early spring seasons were analysed. About 53% of photographs and 71% of pellets contained orthopterans, forming the major component of the harrier's diet. The proportion of reptiles, eggs and birds in the diet were similar across both methods. Presence of other insects in the diet was better estimated by photographs (23%) than pellets (8%) while rodent presence was higher in pellets (17%) than photographs (4%). Pellet analysis and photographs showed similar variation in diet across seasons while only pellets showed variation in diet across regions. Photographs also showed that there is significant variation in diet between the sexes of the species, with higher presence of insects and reptiles in the diet of males than females. Our results suggest that a combination of photographs and pellet analysis provide better estimates of wintering diet of Montagu's Harriers.
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