Birdgirl was an ally of Dr. Mentaur and later Birdman.
On the fourth floor of a partially-demolished building, two strange figures watch a ceremony on the city square below. The mayor of Central City is about to present a medal to Birdman for his many brave deeds. A tall, skinny, bald man in a lilac lab coat and black turtleneck sweater and pants addresses the other figure, a young redheaded woman dressed in a costume modeled on Birdman's and wearing metallic wings: "I've spent many long hours training you for this, Birdgirl. Are you ready?" "Yes, Dr. Mentaur, I won't fail you," replies the woman. The doctor signals one of his henchmen in the cab of a crane, who uses bolt cutters to sever the cable suspending its wrecking ball. As it plummets toward the crowd, Birdgirl flies into view, catches the huge ball, and easily tosses it aside.
Shortly afterward on the ground, Birdgirl converses with the mayor: "Lucky I decided to come by and watch Birdman take the credit for things he never did!" Birdman realizes this is a plot to discredit him and decides to keep quiet until her plan is revealed. "How could you accept this medal under false pretenses?" asks the mayor, but Birdman just flies away.
Back at the Bird Lair, Falcon 7 informs the hero that they've learned the doctor is using Birdgirl to steal hydrogen bombs. "Great Scott!" exclaims Birdman, "If Dr. Mentaur got his hands on that, there'd be no stopping the man! The world would be at his mercy!" At Falcon 7's urging, Birdman and Avenger fly to the nearby arsenal. A major general informs him that they were showing Birdgirl around when she helped some men steal the H-bombs. Using his "atomic compass", Birdman tracks the weapons to a solar desalination plant in the desert.
Watching on a television screen, Dr. Mentaur sees the pair approaching and directs Birdgirl to get some of the atomic grenades and fly up to confront them. Avenger takes the initiative, flying at her as she raises her arm to hurl the grenade in her right hand. Birdman flies in front of his friend, taking the brunt of the blast and plummeting unconscious to the ground. "Take him downstairs to the Hole and lock him up until I figure out how to get rid of him!" the doctor orders his henchmen over the intercom.
The triumphant young woman goes to gloat over her fallen foe, chained in the dark. "That blast finished me, Birdgirl. But before I go, I'd like to see the Sun again," he pleads. She agrees, smugly adding, "There's nothing you can do I can't handle!" Back in the open air, he feels the Sun restoring his strength. "Goodbye for now, Birdgirl," he taunts her as he flies off. She can only exclaim "No! Wait! Come back!" as he is joined by Avenger and climbs higher into the sunlight.
His powers restored, he sees Birdgirl fly up to recapture him, again carrying two grenades. "You tricked me, Birdman, but you're coming back as my prisoner, or..." "Wait," he interrupts her, "they're getting reading to fire those hydrogen shells!" and points to a cannon aimed at them through an opening in the dome atop the plant.
"But this shell will also hit Birdgirl if we fire, Dr. Mentaur," warns one the henchmen aiming the cannon. "That's her problem," replies the villain. "I must get Birdman! Fire!"
Birdman generates a solar shield and flies to intercept the shell. However, the blast still hits Birdgirl. Tumbling out of control, her right wing tears loose as she cries, "Help me!" He dives after her, catching her in his arms and safely returning her to the ground.
"What happened?" she asks, holding her head in her hands. "Where am I?" she continues, the harsh tone that had always been present in her voice now gone. "I think you've been under Dr. Mentaur's influence," suggests Birdman. "Be careful," she calls after him as he returns to the air to attack the doctor's base. Joined by Avenger, he sees a hydrogen shell flying toward them. He uses his solar beam to turn the shell around, sending it back where it came from. The blast destroys the complex. "I think we can write 'finish' to Dr. Mentaur," he tells Avenger.
Returning to where they left Birdgirl, Birdman listens to her disclosure. "I was an aerialist when I met Dr. Mentaur," she confides. "Everything seems blank after that. I can't recall..." "He used hypnosis to make you do his bidding," the hero suggests. "With those wings he created, and super-strength serum, he almost succeeded." "But thanks to you, Birdman, he didn't succeed," she acknowledged. "I'm so grateful." "You'll be all right now, young lady," Birdman replied. "Goodbye," he said as he flew off, leaving her alone out in the desert not far from the radioactive remnants of the hydrogen bomb blast.
- In the "Harvey Birdman, Attorney at Law" series (2001-2007), Falcon 7's daughter, Judy Sebbin, adopted the Birdgirl costume to join Birdman and Birdboy in their adventures.