The pitrs (पितृ) are the spirits of departed ancestors in Hinduism. Following an individual's death, the performance of the antyesti (funeral rites) is regarded to allow the deceased to enter Pitrloka, the abode of one's ancestors. The non-performance of these rituals is believed to result in the fate of wandering the earth as a restless preta. The amavashya (new moon day), as well as the occasion of Pitru Paksha during the Hindu month of Ashvin is recommended for the veneration of pitrs. Ancestor veneration is an ancient Indian practice that emerged in the Vedic religion, dating back to 1500 BCE, during the Vedic period. The custom of a death anniversary is still practised in India, where the deathday of one's parents involves a number of rituals and offerings, that are elaborated in the Puranas. Balls of rice (Piṇḍa) are traditionally offered on certain occasions, due to the belief that one's ancestors still need to be fed by their descendants. For the Brahmins, the members of the priesthood class, a sacrifice dedicated to one's pitrs must be performed on a daily basis. While the Vedic religion held that one's forefathers attain Svarga, the heavenly realm, most Hindus today believe in samsara, the cycle of rebirth, where all departed souls reincarnate on earth until they achieve spiritual liberation, called moksha. According to popular belief, the fire deity, Agni, is believed to carry the deceased to Pitrloka with the smoke that emerges during cremation. The pitrs are often likened to birds, as they are described to always be looking down on earth; the ancient Baudhayana stated that pitrs assume the form of birds. This led to the practice of feeding birds during funeral rites, and rituals associated with ancestor veneration. Texts like the Mahabharata establish the concept of the living performing pious deeds for the benefit of their departed ancestors. Rather than a form of worship, it is stated to be the duty of every male descendant to perform rites for their pitrs.