She is a Pteranodon, which is one of many species referred to as "Flyers" by the characters. She has a big heart toward all the young ones and is protective of her children. She once offered comfort to Ducky's mother when the latter was abducted by Pterano and his minions Rinkus & Sierra. Although she believes her brother would never intentionally hurt anyone, she is quite severe on Pterano, and makes it clear that she does not trust him. She plays a major role in the Great Day Of The Flyers.
Petrie's Mother was kind to her children (although she can be angry sometimes, and was yelling at Petrie in the third film by saying his name and "IT'S TIME TO GO HOME" in a mean voice and he wasn't doing anything wrong). She also gets angry at her own brother, Pterano, since he kidnapped Ducky, alongside his henchmen, Rinkus and Sierra. The second film was the first time she started off to be angry.