Fold the fleece in half lengthwise with the fold at the top.
Place the sweatshirt on the fabric, aligning the shoulders with the fold line. Refer to the diagram to cut a wing shape through both layers of the fabric, beginning on one side and stopping at the center bottom of the fabric. Remove the sweatshirt.
Fold the cut half of the fabric over the uncut fabric and use it as a pattern to cut the remaining side of the wing.
With right sides facing, sew together the cut edges of the wings.
Cut a half-circle neck opening centered on the folded edge.
Turn the wings right side out through the neck opening. Position the wings on the back of the sweatshirt, placing the neck edge of the wings at the bottom edge of the hood.
Sew the wings in place, closing the opening as you sew.
Tack the top corners of the wings to the cuffs of the sweatshirt.
Using the tail diagram as a guide, draw a tail shape on a double layer of fabric, adjusting the length and width as needed.
Cut on the drawn line through both layers for two tail pieces.
With right sides facing, sew the tail pieces together, leaving the top edge open. Turn the tail right side out. Hand-sew the tail to the bottom edge on the back of the sweatshirt.
Hot-glue a length of white boa along the bottom edge of the wings. Starting at the center top of the hood and adhering as you work, spiral around a length of boa 3 or 4 times. Hot-glue the remaining boa on the front of the sweatshirt to make a fluffy chest.
Hot-glue 3 or 4 assorted light brown feathers on each side of the head for ears. Scatter and hot-glue the remaining brown feathers on the chest.