It is mid-September and hawk migration is nearly in full swing! At every migration site, raptors pass overhead in a glide and identifying them on shape is a necessary skill. Red-tailed Hawks are blocky-winged and the primaries jut out from the trailing edge slightly in a shallow glide and a bit more in a steep glide. But did you know that juveniles exhibit longer wings and longer tails than adults? This is very useful information when telling the two ages apart in flight. Check out the picture below of the juvenile Red-tail on the left and the adult on the right, notice the primaries sticking further out on the juvenile, and the wings appear slimmer overall. You can also see the translucent primaries of the juvenile (the adult has pale outer primaries but that is a trick of the lighting in this particular instance - not retained juvenile feathers). Either way, this example shows the difference in shape, and also the difference in color. When seen from below, juveniles appear a simple black and whitish, adults have a pale orangey wash underneath and sometimes darker flight feathers that are often visible even at high altitudes.
Of course, some adults are more colorful than others, and some Red-tails are longer-winged than others by nature, so beware of ageing Red-tails by shape if you haven't practiced it. But use these traits when you feel comfortable, because they are deadly accurate once you "get it.'