Identification: Unlikely to be confused with any other species, except Australian or African Sacred Ibis, which may appear as escapees. Important features to note for Black-headed Ibis are the rather heavy bill, especially at the tip, grey tertials, and limited extent of black on primary tips (or no black at all). African Sacred Ibis has been recorded in Singapore, but that species has much more extensive and darker tertials, and black tips to primaries and secondaries. Australian Ibis may be recorded as an escapee, but has a more slender bill which appears thinner at the tip, more extensive black tips to primaries, and darker tertials.