Naming
* P. p. poliocephalus- Latham, 1801: The nominate subspecies. Found from India and Sri Lanka to southern China and northern Thailand.⤷ P. p. seistanicus- Zarudny and Härms, 1911: Found from Iraq and southern Iran to Pakistan, Afghanistan, and northwestern India. There is also an introduced population in Florida.
⤷ P. p. caspius- Hartert, 1917 : Found near the Caspian Sea, northwestern Iran, and Turkey.

Behavior
The male has an elaborate courtship display, holding water weeds in his bill and bowing to the female with loud chuckles.References:
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