Who Is This White Hawk?

Leucistic red-tailed hawk near Berthoud, Colorado, 2017 (photo by Pat Gaines via Flickr)
Leucistic red-tailed hawk near Berthoud, Colorado, 2017 (photo by Pat Gaines via Flickr)

Have you ever seen a distant white raptor and hoped it was a snowy owl or gyrfalcon?  I have, but I’m usually wrong.  Both species are rare and neither is here in spring or summer.

Snowy owls and gyrfalcons only visit Pennsylvania in late fall or winter.  In most years snowies don’t come to the Pittsburgh area at all (this year is an exception) and gyrfalcons are never here.  In over 100 years only 41 gyrfalcons were reported statewide (see *1 below).

And yet we still see an occasional rare white raptor, even in the summer.  What hawk is this?  In nearly every case it’s a leucistic red-tailed hawk.

“Leucism is a condition in which there is partial loss of pigmentation in an animal resulting in white, pale, or patchy coloration of the skin, hair, feathers, scales or cuticle, but not the eyes.” (quoted from Wikipedia).  The condition is rare but red-tails are our most common hawk so it’s not surprising to find it in a numerous population.

The whiteness varies from hawk to hawk and even from year to year.  Sometimes leucistic red-tails are spotted brown, sometimes they’re entirely white.  Pat Gaines photographed a speckled one in Berthoud, Colorado this winter (above) and an all-white bird in North Denver in 2010 (below).  Neither bird is albino because its eyes are the normal color, not pink.

Leucistic red-tailed hawk in North Denver, Colorado, 2010 (photo by Pat Gaines via Flickr)
Leucistic red-tailed hawk in North Denver, Colorado, 2010 (photo by Pat Gaines via Flickr)

Even the all-white birds have at least one normally-colored feather.  It’s a tail feather on this hawk, as shown in Pat’s photo below.

One red tail feather: Leucistic red-tailed hawk in North Denver, Colorado, 2010 (photo by Pat Gaines via Flickr)
One red tail feather: Leucistic red-tailed hawk in North Denver, Colorado, 2010 (photo by Pat Gaines via Flickr)

So what makes them white?

A study of color aberrations among Indian birds listed six reasons for pale or white feathers. (Download the report here: How common is albinism really? Colour aberrations in Indian birds reviewed.)

  • Albino (pink eyes) is a hereditary pigment error. Albinos are rarely seen because they die young due to poor eyesight.
  • Leucism (normal eyes) is a hereditary lack of both melanin pigments.  Some feathers are normal color.
  • Progressive graying.  Oh my!  A few birds turn “gray” as they age, becoming progressively whiter as they molt each year.
  • Brown. Normally black feathers are brown and sensitive to light so they bleach out in the sun.  This mutation is only expressed in females.
  • Dilution. Black feathers are silvery gray.  Therefore the bird looks pale.
  • Ino is like albino but not as severe. The bird does not have pink eyes and thus lives longer than a true albino.

Even so, we can’t know why each bird is white without a lot of study.

So who is that white hawk in Pennsylvania?  It’s probably a leucistic red-tailed hawk.

 

(photos by Pat Gaines)

(*1) How rare are gyrfalcons in PA?   In 1982 and 1984, DVOC’s Cassinia analyzed all the reports of gyrfalcons in Pennsylvania. From the mid 1870’s to 1984 only 41 were confirmed: Gyrfalcon Records in Pennsylvania, Part One, 1982 and Gyrfalcon Records in Pennsylvania, Part Two, 1984.  Most reports were in Schuykill, Carbon, Berks, Lehigh and Lancaster counties with only 2 reports at Presque Isle, Erie County (there have been more since then).  As of 1984, the most recent sighting of a gyrfalcon in Pittsburgh’s 11-county metro area was 1 bird in Westmoreland County in January 1913.

11 thoughts on “Who Is This White Hawk?

  1. Fascinating clarification of a subject about which many seem uncertain. Regarding gyrfalcon sightings, would my sightings of a gut in the late 1980’s be of interest to anyone in your opinion? This bird seemed to be hanging out nearby for at least a month, I observed it a half dozen or more times in the proximity of two dairy farms that each had a pigeon population, our farm was about halfway between those two. (At the time I didn’t realize how unusual this was or I would have realized better how to share the information with interested parties in a more timely fashion.)

    1. Doug, I don’t know who you could notify except, perhaps, contact the authors of the paper about gyrfalcons (see link) or DVOC.org that published the 1984 paper.

  2. I saw a white hawk (?) today in SE PA. I wasn’t sure what it was exactly, hawk or possibly gyrfalcon, but knew it was special! Thanks for this article as I think this is what it is.

    1. I love raptors. I saw an all white bird of prey in Poughkeepsie NY on 3/19/18 . Not sure what it was , so I started this web querie. Cool.

  3. These wonderful pictures and detailed information definitely help explain what I saw while driving on Rt 168 in Eastern NC. last week.
    Myself, spending much time in the woods and field, I know a hawk when I see one, had just never seen or heard of a white one ( a leucistic red tail). Knew that it was not an owl, due to its head and chest features, wasn’t certain if it could be a falcon, have not seen a gryfalcon. Just knew that it was a white hawk! Good to know and can’t wait for my next encounter, it was really cool! But this encounter was 51 yrs in the making, lol.

  4. I tried posting a pic of a white hawk that is nesting near my home in western Wyoming
    but was denied. It has been around for several years and currently has two chicks. It is definitely a leucitic red tail hawk.

  5. I just saw what I also thought was a white hawk. A very nice encounter for me also. I hope to have another, and hopefully with camera or phone in hand. I live in Opelika Al.

  6. We seen one just outside of Custer South Dakota. He was beautiful. Mostly white with brown on his back and some tail feathers . We seen him twice in the same area.

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