What they feel like

Chickadee
Insubstantial; lighter than the sheet you use to catch it. Hard to tell whether you've caught a bird or just a handful of air.

Crow
Now you know you have a bird, but feathers remain foremost: soft, shiny, and easily rumpled. Rarely runs, rarely struggles. Indignant afterward.

Seagull
Cat-sized and -weighted. Wings and feet are easy to hold, the head wants to snake out. The beak must be grasped firmly between your palm and fingers before the rest will be quiet. Wet job for whomever goes first.

Canada goose
Strong, heavy, stubborn, a double armful. Lies tense but still, cupped against you, until it feels you relax; then fights out with leg, neck, and wings at once. Pose with feet against your thigh, wings between your hands, while someone else manages the head. Hold with all your muscle but without squeezing.