Will opted to use a humane trap to catch and transfer the white kitten because rescue and adoption are part of Flatbush's mission:

Cats are usually scared and may refuse to enter a carrier right away. Many people associate carriers with terrible experiences at the vet's office, or if it was the last thing that occurred to them before they were abandoned. Even if the cats are amiable, traps are a safe way to rescue and transfer them.

It's evident in this video shared by Flatbush and Love Meow that the kitten was glad to see the volunteers and wasn't even afraid of the trap. "I'm ready to find my permanent home!" she said as she went right up to it and got in.