The Indus Dictionary Project
This is a pictograph of a kalij pheasant. Key identifiers for this bird are the crest, and the shape of the tail.
Mohenjo-daro: Seal: M-1831 a: Asko Parpola, B. M. Pande, and Petteri Koskikallio, 2010: Corpus of Indus Seals and Inscriptions: Volume 3,1: Page 57: New material, untraced objects, and collections outside India and Pakistan: Suomalainen Tiedeakatemia.
Unfortunately, there is no photograph of the seal itself in Parpola's corpus. There is only a poor quality image of the sealing. It is therefore, impossible to conclude whether Mahadevan's portrayal of the crest on the pheasant matches that of the original seal.
Indus Script Sign Number 1207: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.