Hypsipetes leucocephalus

Black Bulbul (Hypsipetes leucocephalus) has another split that is Square-tailed Bulbul (Hypsipetes leucocephalus ganeesa)
Black Bulbul is paler in colour compared to Square-tail Bulbul which is much more dark black. Square-tail as name says has much more prominent squared shape tail compared to black bulbul which is more like fork and separated by distribution, Black Bulbul is resident to himalayas and square tailed bulbul is resident to western ghats.