Lydia Brenner (Jessica Tandy)’s Timeline and Summary

Lydia lives in Bodega Bay. Her husband dies about four years before the film begins, leaving her with a son, Mitch, and a much younger child, Cathy.
Mitch starts to date Annie Hayworth; Lydia does not approve and helps cause their breakup.
Melanie Daniels, a socialite who seems interested in Mitch, shows up in Bodega Bay. She sees a good deal of the family; Lydia is maybe a little cranky about this.
Lydia talks to the feed store owner about the fact that her chickens won't eat the feed he sold her.
Birds start to randomly attack people in Bodega Bay.
Lydia makes sure Mitch knows about Melanie's playgirl shenanigans in Italy and questions her character.
She's at Cathy's birthday party when the birds attack the children.
Lydia visits her neighbor and finds his eyes have been pecked out by birds.
This traumatizes her, and she's largely useless for the rest of the film.
Lydia is concerned about Cathy and sends Melanie to make sure she's safe at school.
After Melanie is traumatized by a bird attack, Mitch, Cathy, and Lydia take her in the car away from Bodega Bay, while all the birds watch ominously.