Dietary composition of Black-necked Crane Grus nigricollis Przewalski, 1876 (Aves: Gruiformes: Gruidae) in its winter habitat: insights from fecal analysis in Bumdeling, Trashiyangtse, Bhutan
DOI:
https://doi.org/10.11609/jott.8661.17.1.26341-26352Keywords:
Changing agricultural practices, conservation strategy, declining crane population, fecal dry weight, foraging and roosting behaviour, herbaceous plant, paddy-fields, protein-rich diet, winter habitatAbstract
Gaining comprehensive insights into the dietary habits and food preferences of the Black-necked Crane (BNC) is crucial for developing effective conservation plans to safeguard this globally near-threatened species. The choice of habitats by these birds is primarily influenced by the availability of diverse food sources and overall environmental security. This study was conducted in 2019–2020 in Bumdeling, one of three wintering sites for BNC in Bhutan. It was prompted by concerns over a declining crane population, largely due to habitat alteration that threatens food sources. This study aimed to examine the dietary preferences of cranes by collecting and analyzing fecal samples from foraging and roosting sites. Results revealed that paddy-fields were the primary foraging areas. The presence of domestic grains after harvest, herbaceous plants, and invertebrates are crucial components of the food structure of cranes. Fecal samples contained 79 species from domestic crops, herbaceous plants, and invertebrates. Fecal dry weight exhibited significant differences from December to February compared to March, suggesting a decline in rice intake and an increase in invertebrate consumption, resulting in lower fecal weight. These results also showed that as the months progress rice decreases with a shift to a protein-rich diet of invertebrates before cranes migrate back to their summer grounds. Traces of plastics were found in feces from all feeding sites, highlighting the need for better waste management. Changes in agricultural practices have had significant impacts on the availability of food sources for cranes in Bumdeling. Collaboration among conservationists, local government, and communities is recommended to enhance winter habitats and provide food supplements when rice supplies start to diminish.
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