Harlan’s Red-tailed Hawk on the Breeding Grounds in Alaska
by Bryce W. Robinson
This post details my encounters and notes of Harlan’s Red-tailed Hawks in Alaska during the early summer of 2016. The post is separated into two parts, individuals I encountered while conducting the Alaska Land Bird Monitoring Survey in the remote western interior, and individuals I’ve encountered in the Anchorage area.
From the Innoko National Wildlife Refuge:
I just returned to Anchorage from two weeks of bird surveys in the interior of Alaska, conducting the Alaska Landlord Monitoring Survey for the Boreal Partners in Flight. These surveys entailed travel to three remote national wildlife refuges; Innoko NWR, Nowitna NWR, and Koyukuk NWR. The aim of myself and my friend Nick Hajdukovich was to conduct point counts on refuge land. Our travel consisted of float plane transport to each refuge. Once in the Innoko, we logged 200 miles of river travel on the Innoko River to and from our two survey plots, which provided me with great exposure to untouched Alaskan wilderness. Along the way I happened upon a few individuals of perhaps my favorite bird taxon, the harlani subspecies of the Red-tailed Hawk.
The first birds I encountered on the Innoko River happened to be a nesting pair. Their nest was situated on a partially fallen White Spruce that extended over the open river. As we approached the nest we cut the motor and drifted directly beneath the brooding female. At 200 m from the nest a light morph bird, the male, took flight from a nearby tree and began vocalizing and stooping on our boat (Photo 1, 3). As we floated by, I took the opportunity to document the situation.
It was excellent to observe the defensive behavior. Equally excellent was the light morph plumage of the male, and his silver/white tail with hints of red near the tip (Photo 3). As we passed the dark morph female on the nest (Photo 4), we could see her heavily banded tail, dark and red throughout (Photo 5). The variability in tail pattern in these birds interests me greatly, and it was excellent to see this dark bird with a near wholly red tail.
The female was sitting in the nest, along with one nestling which appeared to be around 15-20 days old. The nestling was panting in the intense Alaskan sun. The temperature was a balmy 70 degrees Fahrenheit, very warm for Alaska. We drifted on, got our fill of photos and satisfying looks, started up the 5 HP motor, and continued our trip.
Throughout our trip we saw a few other adults, all dark morphs that one would consider “typical” harlan’s with whitish and silver tails, white streaked bibs, etc. The birds were uncooperative for photography, except for two individuals that happened to be my most sought after group of this taxon, second year birds midway through their pre-basic molt (Photo 6). I included a photo of one of the individuals, as they were quite similar in appearance and at the same stage in their molt.
The degree of molt which these young birds undergoing is worth noting, as compared to all adults that I’ve seen. All adults, presumably breeding, are limited in the extent of their feather replacement. The two Second-year birds that I’ve photographed are molting heavily, as you can see in photo 6. This speaks to the energetic requirements of both molt and the reproductive effort, and the trade-off in allotment between both, something of which I’ve noted before in Gyrfalcons (find it HERE).
Overall the time spent in the western interior was grossly fruitful in my exposure to Harlan’s alone.
From the Anchorage area:
Something interesting is happening in Anchorage. Although I’ve seen plenty of birds in the region that fit what we call the “typical” Harlan’s (Dark morph, light bib, silver or white tail, mottled flight feathers, etc.), I’ve found two individuals, a pair, that are worth documenting. It’s important to note that I’ve been working in a fairly restricted area on the U.S. Air Force base at the north end of the city. I haven’t been able to cover much area throughout the valley, but much of my assumptions about other Red-tailed Hawk in this region come from observations at Gunsight Mountain Hawkwatch.
The first bird is a light morph female that my friend Laura showed me (Photo 7.). Although it has qualities typical for Harlan’s such as a mottled tail with silver and white tones amidst red, and globular belly markings, it also possesses traits reminiscent of other subspecies such as B. j. abieticola (Northern). Most notable is the barring throughout the wing lining, and on the belly. Also notable is the regular and distinct barring in the flight feathers. The question arises whether this bird’s phenotype is an infrequent but regular occurrence in the harlani population, or a result of integradation somewhere in its recent lineage? Although the area is an intergrade zone for many other species, I’m fully comfortable saying that I don’t know, nor do I want to suggest one over the other. The most exciting part is not knowing, and realizing there is a frontier to explore in our understanding of this species.
The second interesting bird from the area is perhaps more exciting (Photo 8). It shows no indication that it belongs to the subspecies harlani. It resembles a dark morph calurus, with some unique contrasting qualities to the auxiliaries and undertail. I’m not sure what subspecies this bird is, but if I were to guess I’d say this bird fits with the Northern population (abieticola), suggesting that this subspecies is polymorphic. Regardless, This bird along with observations at Gunshight Mountain hawk watch support that the Anchorage area and Matsu Valley are an intergrade zone, as is the case with many other species. I think there remains much to learn about the biogeography of Red-tailed Hawks, especially as it pertains to this small area of Alaska.
Thank you Yvonne!
Hi Bryce, Is it okay to share this post on my Wild by Nature FB group? Security Check Required | | | | | | | | | | | Security Check Required | | | | View on http://www.facebook.com | Preview by Yahoo | | | | |
I would like to but will not unless i hear back from you. Thanks, Dave Barry
Of course Dave. Feel free to link to my FB profile in the post as well. Thanks!
Had to look up “parapatry”. Still don’t quite get it, but understand your beautiful pics. 🙂
Ha! Well mike, I use it in this post to mean that perhaps calurus or alaschensis or whatever you call northern breeding western like birds along the Canadian coast have a range that extend to this point and that the two populations are selectively breeding with their own, where intergradation occurs only at a low rate. The two populations abut one another with little mixing. It’s unlikely, I was just stretching ideas.
I enjoy the blog, thanks for putting so much work into it.
I live in Haines and in April or so I spotted a Harlans hawk on my bike-ride to work. I have a photo (It isn’t the greatest of photos as I only had my cell phone on me at the time) but he/she was really dark. Almost black with a bit of a red-tail. If you’d like to see the photo let me know, but I thought I would share this information with you.
Hi Leia, thanks for the comment. I’m very interested in the Harlan’s around Haines. I’d love to see any pictures you get of birds near your home.
Brilliant stuff! Lovely to see such careful documentation of the plumage variety.
I am live close to the JBER base off Muldoon / 36th area. I saw a very white looking soaring-type bird being chased by about 30 magpies earlier today. It was extremely sunny when walking my dogs today, and it looked like it was flying and being chased over Bulldog Trail (JBER is closed to pass holders right now). I did not get a good look, but the underbelly was very light and it was flapping fast and then soaring. I’m wondering if this might have been the same type of hawk you’re writing about here. Wonderfully informative website.
Most Harlan’s haven’t quite arrived in the Anchorage area quite yet. They usually start showing up around early-mid April. From your description of the flight pattern your bird was likely a Northern Goshawk. Thanks for the comment!
Love your work! My son’s been trying for a while to observe a Harlan’s, any other places near anchorage with regular sightings? Please keep posting such excellent stuff.
It’s about the time of year that Harlan’s move out of Alaska on migration, however come spring you should be able to track some down in the Anchorage area. Pay attention to forest edges where they will be perched on trees or power poles. I know the area near Wasilla has a lot of ag land that would be a good place to check. Additionally, in spring (March-May) there is a hawk watch site on the highway near Gunsight Mountain and Sheep Mountain Lodge. April would be the best time to go to see migrating Harlan’s passing right overhead. Hope that helps! And thanks for the kind words, much appreciated.