Do Dark Northern Harriers Exist?

Three times every winter I drive road transects looking for raptors with other biologists for my Master’s Thesis work at Boise State University. Monday January 9, 2012 was one of these days. I was out with fellow raptor biology graduate student Rob Miller, and fellow biologist Liz Urban, who just recently defended her Master’s thesis work on Urban Cooper’s Hawks in Tuscon, Arizona. While driving along a bumpy dirt road thickly covered in old russian thistle within the Morley Nelson Snake River Birds of Prey Area, we flushed up a raptor little more than 10 feet from the road. The bird quickly flew away and landed down in some sagebrush less than 50 meters from the road. We all looked at each other and said: What the heck was that?

Rob and I climbed out of the truck, Rob lugging his camera-with-token-huge-lens attached (wish I had one!), and proceeded on foot through the sage hoping to flush the bird again to get a closer look. Sure enough the raptor flushed and we got a pretty good look as Rob snapped away grabbing a few good pictures in the 5 seconds we had before the bird flew out of sight again.

The bird was unlike anything Rob, Liz, or I had ever seen. First, it was definitely a Northern Harrier. These raptors fly low to the ground searching for rodents and birds using mostly sound to detect their prey. All of the male Northern Harriers I have ever seen have a conspicuous white rump patch, are slate gray on top, and bright white below with black wing tips. See the photo below of a juvenile harrier.

Juvenile Norther Harrier. Note the white-rump patch. Photo by Beth Orning-Tschampl

However, this bird was totally dark. Both on top and from below on the under-wing coverts, the bird was solid dark gary. Also, the characteristic white-rump seen on almost all Northern Harriers was noticeably absent on this individual! However, the bird is definitely an adult male as we see the black wing tips and yellow eyes present in adult Northern Harriers. We all thought, what the heck is going on? Are there different color morphs of Northern Harriers? None of us had heard of this being the case.

Dark Male Northern Harrier? Photo by Rob Miller.

Upon returning to the lab for the day. I asked my lab mate Eric if he had ever heard of dark Northern Harriers. He said yes, but that he thought they did not exist. Upon seeing Rob’s picture however, he was convinced this was at least a melanistic bird: meaning it has some genetic mutation for creating darker feathers, much like an albino would be. Researching further, I discovered an article from Birding in 2009 by noted raptor expert Jerry Liguori: Read the article here. In the article, Jerry has a distant photograph of a dark Northern Harrier and says “There are now three known records for North America of dark harriers, and this is the only one photographed.” Could we have possibly seen the fourth and only second dark Northern Harrier to be photographed in North America?!?! I think potentially so, and we have an e-mail out to raptor identification expert Bill Clark seeking his opinion on the matter. We will keep you all posted…

Neil Paprocki