Personalized 1st Birthday First Birthday Owl T-Shirt. Our 1st birthday owl design apparel and gifts are ideal for commemorating this special milestone in your baby girl's life. The charming illustrations and vibrant colors make for a delightful addition to the celebration, creating lasting memories for the whole family. Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.