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【蟹...蟹...蟹...】

作為食物鏈頂層嘅褐漁鴞，原來係鍾意食蟹？

經過長達12個月嘅大嶼山夜行調查，我哋發現褐漁鴞喺剛入黑時，經常出沒於河流出口嘅潮澗帶。水漲時，佢哋會企喺水邊嘅樹，或者人工建築物如燈柱、電線杆、碼頭等等；而喺水退時，佢哋會企喺泥灘或沙灘上覓食。

咁究竟佢哋平時食咩？

我哋喺疑似褐漁鴞經常停棲嘅位置，發現大堆白色鳥糞同食繭（註：雀鳥用口吐出無法消化嘅食物），當中含有鼠骨、毛同蟹殼等等，符合最近嘅外國研究嘅發現—褐漁鴞主要係食蟹，魚類佔佢哋餐單嘅一成都唔夠 (Dias & Borker, 2023)。

大嶼山為褐漁鴞等鳥類提供極佳嘅生境棲息，亦係我哋研究褐漁鴞嘅好地方。希望日後有更多有趣發現同大家分享！

*此計劃由 #大嶼山保育基金 贊助 

[Brown Fish Owls actually prefer crabs?]

After twelve months of nocturnal surveys on Lantau Island, we found that Brown Fish Owls frequented the intertidal zone at river mouths just after dark. When the tide was high, they often perched on trees by the water or on man-made structures like lampposts, power poles, and piers. When the tide was low, they stood on the mud or sand flat looking for food.

So what do they eat?

We found some large white droppings and pellets at several locations suspected to be frequent perching spots for Brown Fish Owls. Pellets are undigested foods that birds regurgitate. And inside those droppings and pellets, we found what appeared to be rodent bones and fur, and crab shells. Recent foreign research has also found that Brown Fish Owls ate mainly crabs, with fish making up less than 10% of their diet (Dias & Borker, 2023).

Lantau Island provides an excellent habitat for Brown Fish Owls and is a great place for us to study them. We hope to share more interesting findings with you in the future!

Reference: Dias, S.J. & Borker, A.S. 2023. An assessment of the diet of Brown Fish-Owl Ketupa zeylonensis (J.F. Gmelin, 1788) (Aves: Strigiformes: Strigidae) from two localities in the foothills of the Western Ghats of Goa, India. Journal of Threatened Taxa 15(7): 23514–23520. https://doi.org/10.11609/jott.8415.15.7.23514-23520

*This project is sponsored by the #LantauConservationFund