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Light morph Harlan's RTHA?

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3 minutes ago, smittyone@cox.net said:

This Harlan's was seen earlier the same day about 10 miles away.  I would definitely call this one a dark morph.  But let me see if I understand the differences--It's how dark those markings are, not how much of the bird is covered in those markings?  Am I oversimplifying?




Pretty bird!

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The first bird in your original post has mostly dark underwing coverts, despite having a significant amount of white specking on the breast, as well as solidly dark belly and leggings. So I think it would be considered a “dark morph”, as opposed to a “light morph” which would have paler underwing coverts. And generally a bit paler body as well. 

I put quotations around “light morph” and “dark morph” because in many cases there is not two distinct discrete groups, but typically a complete spectrum of appearances. Often there is a bimodal distribution, so more “light” and “dark” birds and fewer intermediates. But that is not always the case. Certain species of Buteo - especially Swainson’s Hawk - are just extremely variable so much so that they can’t really be classified into color morphs. There’s just such an immense range of intermediates in a variety of colors. On the other hand, Ferruginous Hawks have a pretty strong bimodal distribution, with most birds being light morphs, fewer being dark morph, and then far fewer still being intermediate. (But there is a fair amount of variation in how heavily/darkly the underwing coverts and belly can be marked on light morphs - it’s not like every light morph looks the same!). 

It’s generally true that not every individual (even if they are the same subspecies and color morph) looks the same. Simply put, some dark morphs are darker than others, some light morphs are lighter than others, and there are also intermediates. In general though if you feel the need to call an individual buteo “light morph” or “dark morph”, look at the background color of the underwing coverts. On a light morph Red-tail, the patagial bar might be blackish, but the general background color of the underwing coverts is pale. Dark morphs have solidly pretty dark underwing coverts, maybe there can be a little bit of light speckling, but the general background color of the underwing coverts is dark.

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2 hours ago, smittyone@cox.net said:

Let me know if this one should be in a new thread.  Taken today, about 5 miles away from yesterday's Harlan's.  Is this one also a dark morph Harlan's?  Taken under dark overcast skies, so original pic was severely underexposed, then brightened in post.  


So no, I would not call that a dark morph, it has pale underwing coverts with darker markings on them, rather than having dark underwing coverts like the first bird

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The birds with extensive white streaking on the breast, including the original bird in question, are intermediate morph Harlan's. The very dark Harlan's that was stated to have been photographed about 10 miles away from the original bird is certainly a dark morph bird. As Alex stated above there is quite a range even within subspecies like Harlan's. Some authors break it down even further and describe the intermediate morphs as "dark intermediate morph", "light intermediate morph", etc.

The last hawk photo submitted in this thread is a juvenile bird and with the amount of spangling below I'd also call it an intermediate morph Harlan's.

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