This weekend we did see quite a few Sharp-shinned hawks. One of the things I always find interesting is the difference in plumage within-species. Both of the birds pictured here are juvenile, or hatch year, Shins. But look at the differences in plumage - the first bird is much darker around the face. The second bird has a very light brow, too. Keep in mind that they are both migrating over the same area, so were probably fledged north of where we were.
We banded two Merlins over the weekend, so you can make some comparisons here, too. The second bird is much darker. There is not a difference in plumage here between male and female as far as juvenile plumage, though there will be when they are adults.
Finally, we did band a juvenile Kestrel. Look at how the spots continue so far up the chest. On an adult bird, even though the pattern will be different on each individual, the spots will stop somewhere about mid-chest.