Changes in the Montagu’s Harrier Circus pygargus diet in Eastern Poland across decades promote insects and reptilians, but not birds and rodents

Kitowski, Ignacy; Jakubas, Dariusz; Mirski, Paweł; Pitucha, Grzegorz; Markowska, Kornelia

doi:10.1002/ece3.7416

Cited by 3 publications

(2 citation statements)

References 43 publications

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“…lizards (own data). Although previous studies have recorded the presence of seasonal variation in Montagu's Harrier diet concerning their breeding periods (Arroyo 1997, Kitowski et al 2021, this is the first time such a variation is being documented in their wintering regions.…”

Section: Diet Variation Across Itinerancy: Do Montagu's Harriers Swit...mentioning

confidence: 68%

Diet of Montagu's Harriers Circus pygargus Wintering in India: Analysing Seasonal, Regional and Sex Differences Using Web-Sourced Photographs and Pellet Contents

Kannan

Thalavaipandi

Mehta³

et al. 2023

Acta Ornithologica

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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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Section: Diet Variation Across Itinerancy: Do Montagu's Harriers Swit...mentioning

confidence: 68%

Diet of Montagu's Harriers Circus pygargus Wintering in India: Analysing Seasonal, Regional and Sex Differences Using Web-Sourced Photographs and Pellet Contents

Kannan

Thalavaipandi

Mehta³

et al. 2023

Acta Ornithologica

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“…Contrary to invertebrates, fire caused an immediate decline in the density of small mammals, especially the disappearance of the most common rodent species in the valley-the root vole Microtus oeconomus (Borowski et al in preparation). Rodents are a basic food item for all three birds of prey negatively affected by the fire-short-eared owl (Lesiński et al 2016), montagu's harrier (Kitowski et al 2021) and marsh harrier (Brzeziński and Żmihorski 2009). Since the availability of prey is one of the main factors influencing population densities and habitat use in birds of prey (Korpimäki and Norrdahl 1991;Newton 2007), the temporal absence of rodents could largely contribute to the observed short-term decline of these species on burned areas.…”

Section: Bird Community-short-term Response To Firementioning

confidence: 99%

Large fire initially reduces bird diversity in Poland’s largest wetland biodiversity hotspot

et al. 2022

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Freshwater wetlands are widely recognized as biodiversity hotspots for many organisms, including birds. Climate change and the projected increased risk of wetland fires may pose a major threat to wetland biodiversity in the future. There is urgent need to assess short- and long-term effect of fires on avian biodiversity and to establish relevant management implications. We analysed the short-term (first 3 months after fire) effect of a large (5 500 ha) spring wildfire on the community of breeding marshland birds in the best-preserved Polish local wetland biodiversity hotspot: Biebrza Valley. We compared the avian community structure and abundance of certain species before and after the fire on the 18 permanent transects located in both burned and unburned habitats. Within first breeding season post fire, fire significantly reduced pooled abundance and species richness of the whole bird community. Three bird species of special conservation concern (including aquatic warbler) temporarily disappeared from burned areas, and the numbers of 11 other species declined. In contrast, only 3 species benefited from the fire, none of which depended on marshes as their primary habitat. Although the reported strong initial fire effect is likely to fade away in subsequent years, its immediate detrimental effects on marshland birds should not be underestimated. We conclude that it is essential to temporarily provide the unburned adjacent refuge areas with additional protection and bird-friendly management and to focus on preventing further degradation of marshes to increase their resilience to fire.

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