Wednesday, September 11, 2013

In-flight Field Marks of the Juvenile Red-tailed Hawk

10 Sep 2013, Lake Norris Conservation Area

In-flight Field Marks of the Juvenile Red-tailed Hawk
The two images below are of the same juvenile Red-tailed Hawk that I observed 10 Sep 2013 at the Lake Norris Conservation Area, Lake County, FL.  The terminology you hear and see is usually not mentioned in the typical field guides because field guides are designed to be brief.  This overview will mention some of the most common terms used when describing a Red-tailed Hawk; some terms apply to all birds.
Underside view:
CLICK TO ENLARGE; "X" in upper right to go back
A key field mark of the juvenile Red-tailed Hawk is how much darker the secondary flight feathers are compared to the primary flight feathers.  In clockwise rotation, p10 is the most forward primary feather, then you see where I noted where p6 is;  p1 is next to s1. 

Look closely at the entire s1 feather (and the rest of the secondary feathers) and you see the dark coloration compared to the primary feathers; compare closely p1 to s1 to see how the primaries and secondaries differ.  This is why there is a "window" or "panel" shown in the image below.  The ten primary feathers lack this dark coloration thus creating the wing panel or translucent window.  p10 though p6 may show dark tips but the base is still light.
The counting order is simply different with the secondaries.  Think of it as a rocket lifting off.  p10, p9, p8, ...p1, then s1, s2, s3 etc. as you get closer to the body of the bird  There is no zero.
In the image below, from the topside, you will see how this "translucent window" or "wing panel" appears.
The "terminal band" on the tail is 2 to 3 times wider than the rest of the thin dark bands on the juvenile.  Some authors may describe this as the "subterminal band", meaning the second to the last band (counting toward the tip of the tail).  The tip of the tail is white.  In some raptors or other birds, if this white edging is wide enough, it will be referred to as the terminal band and then this wider band in this image, in that case, may be referred to as the subterminal band.  No need to get confused here because in nearly all cases, they are simply referring to a wider band at the tip (or near the tip) of the tail.  The adult usually lacks the tail bands but often retains a line or thin dark subterminal band.  Tail banding is usually not seen in the field, even if clear in close-up photos.
The "patagial mark" is the dark bar on the patagium, as illustrated above.  Sibley's Field Guide refers to "the dark mark on leading edge of underwing".  This is the #1 field mark in nearly all subspecies of the Red-tailed Hawk.  If you see a patagial mark in Florida, you can rule out any other raptor with a high degree of confidence.  This mark is unique to the Red-tailed Hawk.  If it is not, then it is an anomaly. 

The streaking in the belly, the "belly band", is another key mark for the Eastern subspecies (certain subspecies it will be missing) but some other raptors can show some streaking here.  Usually, it is so prominent and contrasts with the clean white chest so much that it is the #2 key field mark for Eastern Red-tails.  The belly band is easier to see than the dark area on the patagium at a distance.

The white chest contrasts with the belly band in Eastern Red-tails.  Other Florida buteos usually show some streaking or spots on the chest.
Unlike the patagial mark, the "comma" is not unique to the Red-tailed Hawk.
Top-side view:

This is the same hawk as above but further away.  The "bulge" is often prominent in the Red-tailed Hawk, illustrated here by the third red line from the top.  This is a key mark.  Other Florida buteos don't show a prominent bulge.  If you note the first image from the underside, you really don't see this bulge well.  The hawk in this topside view is more into a soar with the "hand" or outer primaries pushed forward and that exaggerated the "bulge", something you will often see or hear when birders describe a Red-tailed Hawk.
Look how obvious the wing panel is, illustrated by the area between the top two red lines.  The Red-shouldered Hawk has a crescent shaped wing panel that is much smaller.  The juvenile Red-tailed Hawk has a large square shaped wing panel that, as you saw from the above image, is created by all ten primary feathers being lighter colored than the secondaries.

If you go to my Aug 21, 2013 blog post, I show a side-by-side view of an adult and juvenile Red-tailed Hawk and you can see where the adult lacks the wing panel.
Other topside marks:  The tail is not red because it is a juvenile.  The white area in the rump has thrown birders off, thinking they saw anything from a Golden Eagle to a Snail Kite to a Cooper's Hawk, to a Northern Harrier, et al.  This image shows the tips of the first four primaries turned up but that is not a diagnostic mark.  The Short-tailed Hawk more commonly shows upturned wing tips.

As a final note, new birders need to remember what a field guide is.  The key word is “field”—these guides are brief and small, designed to carry into the field so you do not get detailed descriptions and explanations of terms used.  That is what a desk reference is for or an online reference such as Birds of North America Online.  Hopefully, new birders picked up some tips here to not only help ID a Red-tailed Hawk but to know what some of this terminology means.


  1. First of all, I can't believe I had not found your blog long before now! I have a lot of catching up to do on your previous posts.

    Secondly, excellent article! Thank you for sharing your expertise. This sort of "continuing education" is invaluable and we all need a refresher course on the basics from time to time.

    Happy to have found you here!

    -Wally, Lakeland, FL

  2. I second what Wally has just stated. This was my first 'bird of prey' tutorial and I have a feeling it wont be my last. I have an Audubon walk sometime in October that will address the migration of the hawks and I look forward to that as well. Thanks for getting that ball rolling for me - the rocket count down is something that I will remember too! Thanks a bunch.

  3. Thank you Wally and France. I know some excellent birders--I mean excellent--who struggle with raptors. I struggle with pelagic birds and until one year ago, I struggled with warblers. Learning to ID any family of birds or any order of birds just takes some explanation, something that field guides do not do. All newer birders need to realize that field guides show you pictures but do a very poor job (by design) in giving explanations. Finding resources to give you that detail, such as the Brdbrain listserv e.g., a desk reference perhaps, or an online resource can give you detail that the field guide never can.