Today is Mahalaya Amavasya, also known as Mahalaya, the last day of the Pitru Paksha (the fortnight for the ancestors) and also the final day to offer oblations to ones ancestors. According to Hindu religion, the souls of the three preceding generations reside in ‘pitru-loka’ a realm between the earth and the heavens and governed by the Lord of Death, Yama. However, during the pitru-paksha, the souls come down to earth and hover around the homes of their descendants and it becomes imperative for the descendants to feed their hungry souls. One of the ways to feed them is to feed the poor, though feeding the crows (also considered to be harbingers of death) or cows is a ritual many follow during the fortnight.
Details and significance of the day can be read in my article “Mahalaya” dated 7/10/2010 in the link - http://utkarshspeak.blogspot.com/2010/10/mahalaya.html