Returning home, Willow discovered that she could understand Lebowitz as clearly as if they were both speaking English, and that she had developed super-sensitive olfactory senses as well as canine instincts. With Lebowitz's guidance, Willow began training her strength, reflexes, agility, and self defense ability to a degree that she was able to adopt the costumed identity of Whistle and put a stop to Poison Ivy's activities in Down River.

Whistle and Lebowitz later spent some time training at the short-lived Titans Academy under the original Teen Titans, including fellow Gothamite Nightwing.

• Animal Empathy: Due to both her powers and familiarity with canines, Willow can communicate intent and needs to ordinary dogs, acting as their leader.
• Psychic Bond: Willow and Lebowitz have a psychic connection that allows Willow to understand Lebowitz's canine utterances as human speech.
• Scissors Combat: Willow has independently developed an unconventional fighting style utilizing a pair of ordinary scissors as a weapon, striking with the finger rings as a blunt weapon or the shearing portion as a blade.
• Superhuman Hearing: Willow is capable of clearly hearing conversations through several walls in active environments like schools and hospitals.
• Superhuman Sense of Smell: Willow's olfactory sense is on par with the best bloodhounds, refined enough to track specific people or animals through the dense sensory landscape of Gotham City, even amidst strong smells like the fish stand at the local Farmer's Market.
• Whistle Call: attuned to her animal empathy, Willow can make a clear, resonant whistling that reaches over a great distance to act as a summons to ordinary dogs in the area.
• Linguistics: Willow is a native speaker of English, and is familiar with some Hebrew and Yiddish.
• Martial Arts: Willow has trained to a relatively high degree of competency in kickboxing and self-defense.
• Skateboarding: Willow has trained in skateboarding since childhood, and has a high degree of skill at the amateur level, allowing her to utilize a skateboard as transportation.