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Gray Hawk (1 Viewer)

Richard Klim

Richard Klim

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Millsap, Seipke & Clark 2011. The Gray Hawk (Buteo nitidus) is two species. Condor: in press.
www.jstor.org/stable/10.1525/cond.2011.100089

B nitidus Gray-lined Hawk
B plagiatus Gray Hawk

  • Monroe & Sibley 1993 recognised Asturina nitida Grey-lined Hawk and A plagiata Grey Hawk.
  • AOU recognised A plagiata Mexican Goshawk until the Check-list 4th ed (1931), at least. [Lumped in the 5th ed (1957).]
 
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And so we go back and forth ;)

If anyone has access, what are the new data?

thanks
Niels
 
Abstract

Mysticete said:
PS if someone could repost the abstract...
Click to expand...
"We compared the plumage, morphology, and the alarm call of two taxa of the Gray Hawk (Buteo nitidus) from north and south of a distributional gap in the species’ range in Costa Rica. We found all age and sex classes completely distinguishable on the basis of several discrete plumage features. Three of four age and sex classes were diagnosably distinct by measurements of external morphology alone, and the two taxa had diagnosably different alarm calls. On the basis of the level and stability of morphological differentiation, and consistent with prior work suggesting substantial genetic differentiation between the two taxa, we recommend they be recognized as full species, B. nitidus, the Gray-lined Hawk, south of the distributional gap in Costa Rica, and B. plagiatus, the Gray Hawk, north of the gap."
 
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I thought I had seen somewhere a discussion of exactly where in Costa Rica the proposed gap exists. Anyone know where?

thanks
Niels
 
njlarsen said:
I thought I had seen somewhere a discussion of exactly where in Costa Rica the proposed gap exists. Anyone know where?

thanks
Niels
Click to expand...

Well, according to the paper, Gray Hawks only occur in the northwest while Gray-lined Hawks occur elsewhere, including the Caribbean slope. However, I think this merits further studies carried out in the field because the only place where I have seen Gray-lined Hawk in Costa Rica is in the southwestern lowlands. Not that they dont occur elsewhere but every taxon of this complex I have seen around Carara and on the Caribbean slope have been definite Gray Hawks.
 
Snapdragyn said:
Unless it was an extralimital bird, the caption on the photo is incorrect (says it's a Grey-lined Hawk in Belize).
Click to expand...

Corrected now - the photo is certainly of a Grey Hawk using the ID criteria in the paper, and the same picture - credited as being from Belize - is also used in the paper. Sorry about the typographical switch-over!

D
 
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