Mugger Crocodile Crocodylus palustris (Lesson, 1831) predation on Brown Fish Owl Ketupa zeylonensis (J.F. Gmelin, 1788), with notes on existing literature regarding their predation on birds

Several observers have noted that Mugger Crocodiles Crocodylus palustris incorporate birds into their diet, though no authors have reviewed the full range of bird species subject to such predation. In the present study, the first observation of Mugger Crocodile predation on an owl, specifically the Brown Fish Owl Ketupa zeylonensis, is reported. Additionally, the existing literature regarding Mugger Crocodile predation on birds is summarized.

The Mugger Crocodile Crocodylus palustris (Lesson, 1831) is a medium-sized crocodile distributed across the Indian subcontinent and bordering regions.It is listed as a CITES Appendix I species and considered 'Vulnerable' by the IUCN Red List (Choudhury & de Silva 2013).Researchers have reported it to be a generalist predator, with its diet at various age classes including invertebrates, fish, amphibians, reptiles, birds, and mammals (Whitaker & Whitaker 1989;Bhatnagar & Mahur 2010).
On 23 March 2023 at 0814 h, the authors were rounding a bend on the Girwa River in Bardiya National Park, Nepal (28.4719 N, 81.2468 E), when an observation of a Brown Fish Owl Ketupa zeylonensis (J.F.Gmelin, 1788) wading in shallow water at the river's edge was made.At that moment, a Mugger Crocodile burst from the water and caught the owl in its jaws.Upon securing the bird, the crocodile appeared to respond to the authors' presence by swimming away and concealing itself beneath the cover of a submerged tree.The owl was confirmed as a Brown Fish Owl by Valia Pavlou of the Natural History Museum of Crete due to the pattern of the feathers (Valia Pavlou pers. comm. 25.i.2024).Photographic vouchers of the crocodile with the owl were deposited in the Zoological Reference Collection (ZRC) of the Lee Kong Chian Natural History Museum.
A literature review of observations of birds in the diet of Mugger Crocodiles reveals several instances.Battye (1945) witnessed a crocodile taking a struggling "whistling-teal" that he had just shot in a lake in Basur, Bastar State (modern-day Chhattisgarh, India).Whitaker (1978) reported Cattle Egret Bubulcus coromandus feathers in crocodile dung in Gir National Park, Gujarat, India.Whitaker & Whitaker (1989) cited "various authors" as reporting mugger predation on "egrets, herons, kites, waterhens, peacocks, dabchicks, and pigeons", later specifying the Brahminy Kite Haliastur indus in particular.A scat study by Kumar et al. (1995) in Manjira Wildlife Sanctuary, Andhra Pradesh, India, found feathers of Cattle Egret, Little Cormorant Microcarbo niger, and Eurasian Coot Fulica atra in crocodile dung.The authors of that study also observed direct predation on an Eurasian Coot and Purple Moorhen Porphrio porphrio.Jayson et al. (2006) reported that reintroduced Mugger Crocodiles in the Neyyar Wildlife Sanctuary of Kerala, India, predated domestic ducks.Venugopal (2006)   of Mugger Crocodile prey items in the Savitri River of Maharashtra, India were birds, predominantly egrets and herons.That study also detailed flight initiation times in response to the Mugger approach for 26 bird species across 11 families and suggested that crocodiles were using sticks as bait in order to lure birds closer to them.The results of this review are summarized in Table 1.
The observation thus represents the first published record of Mugger Crocodile predation on an owl (Raju Vyas pers. comm. 8.i.2024;and this review).This event is well-situated within the recorded literature of bird predation by Mugger Crocodiles, which primarily encompasses medium-to-large bird species associated with water-specifically wading birds, large shorebirds, rails, ducks, and aquatic-feeding raptors.
The literature survey also suggests that birds are a regular but not dominant feature of Mugger Crocodile diets in many parts of their range.