Many 1st-year (juvenile) Sharp-shinned Hawks are heavily marked underneath and appear adult-like. I attached a few good examples of this plumage type (note their brown faces, blobby markings on the chest/belly, and yellow eyes that qualify them as 1st-year birds)...it is common on females and less common on males. 1st-year Sharp-shinned Hawks in fall are in complete juvenile plumage, and have not yet molted (their first molt occurs the following April through summer) so they lack any adult feathers. However, some show barred-like flank feathers that are very similar to the barred underside feathers of an adult bird, and it is easy to confuse these 1st-year feathers for new adult feathers. So look out for these 1st-year birds that can look adult-like in the future. The frontispiece image shows a good example of the similarities between an adult bird on the left and a 1st-year bird with an adult-like underside on the right. There's always more than meets the eye when it comes to bird ID...which makes it fun!