Notes: Slightly hooked bill, rounded tail tips. Broad black lores.
Grey upperparts, blackish wings, white underparts. Ssp leucura has head
& neck much lighter & greyer than nominate, not contrasting with back;
breast strongly washed grey. Ssp cinereiceps is similar to previous, but
upperparts browner. Ssp alligator has crown, neck & ear-coverts much blacker,
contrasting w. upperparts, pale grey wash on breast. Voice is a plaintive, slow,
whistled note, usually repeated.