Dr Robin Banerjee and Salim Ali teamed up to find out the mystery behind bird-harakiri at Jatinga valley in North Cachar Hills. Dr Banerjee said: "Usually, birds which fly during daytime do not fly at night but a visit to Jatinga proved me wrong" Some birds which usually fly during daytime, are also known to fly at night. The reason behind the mysterious deaths of birds, he found out, was not suicide but misty nights, northwest wind and a full moon.