Festivals and celebrations are essential parts of our survival as human beings. In India there are celebrations for every occasion: I love this part of my culture. Shraadh or Pitru tarpan or kaagvaas is that time of the year where we remember our ancestors. It's surprising that this celebration falls around the same time with the Mexican celebration of Dia de los Muertos (day of the dead) and the american celebration of Halloween. I am sure somewhere in collecting candies and dressing up as strange creatures, Halloween must have had some connection with the dead world or the ones that have moved on.
During Shraadh, many Hindus believe that their ancestors’ spirits come to visit them in the form of crows. Crow in native american culture is a bird that carries the mystery of life. As the word Shraadh comes from the root sanskrit word for Faith- Shraddhaa, this is a matter of belief. Gujarati tradition is to make Doodhpaak (rice, milk pudding) and Puri(deep fried wheat baby chapatis) and put it out on your yard to feed it to those “ancestors” that may come to visit. Some choose to reminisce the good times with those that are no longer on this earth while some choose to ask forgiveness from those whom they may have hurt during their time on this earth.
According to Wikipedia, Shraadh is: “In the Hindu religion, it is the ritual that one performs to pay homage to one’s 'ancestors' (Sanskrit: Pitṛs), especially to one’s dead parents. Conceptually, it is a way for people to express heartfelt gratitude and thanks towards their parents and ancestors, for having helped them to be what they are and praying for their peace.
It can also be thought of as a "day of remembrance." It is performed for both the father and mother separately, on the days they became deceased. It is performed on the death anniversary or collectively during the Pitru Paksha or Shraaddha paksha (fortnight of ancestors), right before Sharad Navaratri in autumn.”
Now you know why your Gujarati parents follow this tradition of shraadh.