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"Brown Harriers"

posted by Jerry Liguori at
on Monday, September 23, 2013 

One of the trickiest aspects of hawk identification is telling adult female from juvenile Northern Harriers at a distance. Most people are familiar with the rusty colored, essentially unmarked underbody of juveniles versus the paler buffy, streaked underbody of adult females. However, adult females can show rusty undersides (more commonly in the West) and appear very similar to juveniles, and the underside of juveniles fades to buffy by winter/spring and can appear similar to that of an adult female.

Before "clicking" on the composite above to enlarge it, note the overall color of the 4 birds as they would appear in the field. The 2 left-hand birds appear orangey underneath as you would see on typical juveniles, and the 2 right-hand birds appear buffy resembling adult females. Now enlarge the photo and see that the 2 adult females (1st and 3rd bird from Utah, November) show streaking on the body, and the 2 juveniles are basically unmarked on the body. The 2nd bird was photographed in September and the faded juvenile (last bird) was photographed in December in Utah. Consider that, if the lightly marked adult female was an orangey type, it would be nearly impossible to tell from a juvenile without ideal views.

Yes, there are other plumage differences between adult female and juvenile Northern Harriers (topside color, marked undertail coverts, head pattern, etc.), but they are minor and difficult to pick out without considerable experience. Telling Harriers from other hawks can be difficult, so classifying a "brown" Harrier as unknown age/sex shouldn't be a bother. Too often, I have seen birders 'shoot from the hip' when ageing Harriers never aware they were incorrect.


9 Comments:
Blogger Mia McPherson said...

Interesting information as usual Jerry!

September 24, 2013 at 5:26 AM  
Blogger Bryce said...

One thing that impresses me about this post is that you can talk about everything, and then supplement your ideas with photos. There is something to be said about that alone, Jerry.

I'm glad you detailed this dilemma. Very useful information that I know I'll surely be applying next time I'm on a ridge (hopefully tomorrow).

September 26, 2013 at 7:54 AM  
Blogger Jerry Liguori said...

Thanks Bryce

You are right on the money with the photos comment!!!

September 26, 2013 at 8:01 AM  
Anonymous Ron Dudley said...

This has been an ID dilemma for years with me, Jerry. Very helpful. I saw Ted Floyd's recent ABA blog mention of your take on aging male harriers - pretty neat!

September 27, 2013 at 5:27 AM  
Anonymous Jerry Liguori said...

Thanks Ron!

September 28, 2013 at 3:45 AM  
Anonymous Dan Wyment said...

Wow, I didn't realize the brown harriers could be that difficult..I always called orange ones immatures and pale ones females. Can't imagine now how many times I screwed that up?

September 30, 2013 at 12:57 PM  
Blogger Jerry Liguori said...

Dan

Thanks for commenting, I still see that happen often. Spring harriers are even tougher to age at a distance.

October 1, 2013 at 7:29 AM  
Blogger Ken said...

Thanks for this post! So, if I understand you correctly, the key mark is streaking on the ventral body (throat doesn't count, it appears) - if it's streaked there, the bird is likely an adult female (in this context) and if unstreaked it's a juvenile? And the color of the underparts can be misleading. Let me know if that's wrong...

October 1, 2013 at 10:19 AM  
Blogger Jerry Liguori said...

Hi Ken

Essentially, yes...some other things too, but for field views the streaked vs unstreaked (although juveniles do have some streaks) is the best way to tell simiarly colored birds apart. Of course, a whitish bird, or a molting bird, in fall will be an adult.

Jerry

October 1, 2013 at 1:56 PM  

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