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Determining Age and Color-type of Swainson’s Hawks: Part 3 – Juveniles

Alex Lamoreaux|

This is the third post in a series about ageing and determining color-type of Swainson’s Hawks, the first post focused on telling age, the second post focused on telling color-type and sex of adults and this post will focus on determining color-type of juveniles.

Unlike adult birds, juvenile Swainson’s Hawks cannot be sexed in the field by plumage characteristics. However, juveniles can easily be separated into particular color-types. in my opinion, there are three main color-types worth knowing when talking about juveniles; these are the light type, light-intermediate type, and dark type. These three types are the ones most commonly encountered (from my experience). There are officially five different color types in total, however.

As I mentioned in earlier posts, lighter birds make up about 90% of the population for Swainson’s. Of that 90%, pure light-types are the most abundant, and what most birders are used to seeing, so I will start with discussing the light type juveniles, but first I should point out a few general juvenile traits. Many juvenile birds show a very light-colored head in their fresh, right-out-of-the-nest plumage, and by late spring and summer later that year, they may be very, very worn-looking and so even lighter heads and duller plumage as they begin to transition into subadult plumage. This should be taken into account, when trying to determine color-type since a bird could become so faded and bleached, that it may, at first glance, resemble a color-type that it is not. Also, remember from my first post, that juveniles birds lack ‘bibs’, lack a very defined black trailing edge to the wing, and lack a wide subterminal band; the subterminal band on juveniles is rarely wider than any other band on the tail. Juvenile birds also have light yellow eyes, whereas adult have darker, almost black eyes. Juvenile birds almost always show feathers on their upper side heavily edged with tawny coloration.

Light type Juvenile:

So, the light-type juvenile Swainson’s Hawk show a very pale, usually almost white head with a few darker markings, especially dark malar marks. Sometimes like in the photo below, they can have slightly browner heads. These malar marks usually run down and form markings around the sides of the throat and then continue down to form weak streaking throughout the belly. The underwing coverts are typically completely unmarked, and just appear white. Sometimes, the underwing coverts will show a very narrow string of small dots extending from the body, outward, about midway through the coverts. The leg feathers are white, with no markings.

Swainson's Hawk - light type juvenile; Note white head with minimal brown markings, weakly-marked breast, and very lightly marked belly. Underwing coverts almost all white. Subterminal band barely wider than any other band on tail.

 

Swainson's Hawk - light type juvenile; Note very pale head. Subterminal band is the same width as all other tail bands.

Dark type Juvenile:

The second color-type is the dark type. This type is overall a dark grayish-brown or sometimes black. The head is very dark. The breast and belly is heavily marked with dark feathers throughout. The underwing coverts are very heavily marked, but variable from very dark to some with a decent amount of lighter feathers. The upper side is the same color as the underside. The undertail coverts are typically lighter in color than the rest of the body.

Swainson's Hawk - dark type juvenile; Note very heavily marked breast, belly, and underwing coverts. The head is much more heavily marked than light types. The undertail coverts are light.

Swainson's Hawk - dark type juvenile; Compare this upperside to the upperside of the light type juvenile. (This bird is the same individual as the other dark type pictured above)

Light-intermediate type Juvenile:

The final color-type that is most often encountered on juveniles is the light-intermediate. This type is very, very similar to the light type but shows more markings on the breast and belly, extending farther down. The leg feathers are lightly marked. The upperside of the bird looks almost identical to the upperside of light types.

Swainson's Hawk - light-intermediate type juvenile; Markings on breast and belly extend to legs.

Those are the three color types that I have encountered most often in the field, however, like I mentioned, there are a few other types the juvenile birds can come in. The other types (intermediate, dark-intermediate, rufous) are just get more and more heavily marked versions until you reach the birds that are considered dark types. If you have any questions about this post, please contact me by leaving a comment or emailing me (alamoreaux@verizon.net).

All photos on this post were taken by myself and cannot be used without my permission.

About the Author

Alex Lamoreaux

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Alex Lamoreaux has been an avid birder and naturalist since he was a youngster, growing up exploring the farmland and Appalachian ridges near Hershey, Pennsylvania. He attended Penn State University, studying wildlife biology. Alex has traveled extensively throughout North America, Central America, and South Africa and is a freelance nature tour guide, field biologist, and wildlife photographer. Alex has worked on wildlife research projects ranging from Whimbrel migration along the coast of Virginia to Yellow-billed Cuckoo nesting in the desert southwest. He has been the migration counter at the Hawk Ridge Bird Observatory for the past two fall seasons, documenting the massive visible migration of raptors and songbirds along Lake Superior. Alex loves to share his knowledge of nature, and strives to bring the birding community together to share in the fun that studying birds and wildlife has to offer. He has helped to organize and coordinate birding events in his home state of Pennsylvania and beyond. Contact Info Alex Lamoreaux aslamoreaux@gmail.com (717) 943-7086

  • Cathy

    Useful series – thank you!

  • Mary

    Are Swainson’s likely to show up in January in Alabama? As juveniles?