Monday, July 13, 2015

2015 AOU Check-list Supplement

Roadside Hawk - Catherine Hamilton
The American Ornithological Union recently released its 2015 Check-list Supplement (available here). There are a few changes that will be of interest to raptor aficionados and hawkwatchers in this year’s supplement. Coincidentally most of them seem to affect raptors that we hope to see on our Raptors of the Rio Grande Valley Tour in November (link here). 

One change is a new genus and sequence for both White-tailed and Roadside Hawk. White-tailed Hawk makes a change from Buteo albicaudatus to Geranoaetus albicaudatus based on genetic data. This means that White-tailed Hawk moves into a genus with Variable Hawk and Black-chested Buzzard-Eagle and becomes the only North American Geranoaetus. White-tailed Hawk is mainly restricted to coastal southern Texas in the USA and can be found southwards all the way to Argentina.

White-tailed Hawk - Catherine Hamilton
Roadside Hawk also comes out of Buteo into its own genus Rupornis. This species has a number of subspecies, some of which may well deserve species status, and can be found from Mexico south to tropical South America. Though considered a mainly resident species there are eight winter records of the species from the Rio Grande Valley, TX (so we will keep our fingers crossed).

New Buteonine Hawk Sequence: Roadside Hawk, Harris’s Hawk, White-tailed Hawk, Gray Hawk, Red-shouldered Hawk, Broad-winged Hawk, Hawaiian Hawk, Short-tailed Hawk, Zone-tailed Hawk, Red-tailed Hawk, Rough-legged Hawk, Ferruginous Hawk 

One of the other species we will see in Texas is involved in a small change as Crested Caracara comes out of its subfamily Caracarinae and moves into the family of true falcons: Falconinae.

Northern Harrier -  Rick Bacher
One of the proposed changes that was not accepted but might be of interest to raptor fans, hawkwatchers and maybe more specifically raptor banders was the proposal to split Northern Harrier (Circus hudsonius) from Hen Harrier (Circus cyaneus). There is currently one accepted record of the European subspecies from a wing found on the Aleutians in 1999, though Howell in his comments in Rare Birds of North America (Princeton University Press 2014) suggests that there are other promising reports out there including one from New Jersey in 2010. The book also has a good overview on separating the two subspecies: relatively easy with adult male Hen Harriers which are much cleaner grey and white and with six black primaries, much less so with females and juveniles. Juvenile Hen Harrier averages streakier than Northern and much less cinnamon/orange overall. You can read a good perspective on the ID challenge from Julian Hough on Birding Frontiers (details here) and read an account of the Cape May bird (link here). Getting extensive photos of interesting birds would be highly recommended!

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