Ornithologi

A studio for bird study

Tag: jamaicensis

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:

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Photo 1. Adult male light morph “Harlan’s” Red-tailed Hawk (Buteo jamaicensis harlani). Innoko National Wildlife Refuge, Alaska. Photo copyright Bryce W. Robinson.

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.

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Photo 2. Innoko River, Innoko NWR, Alaska. June 2016. Image copyright Bryce W. Robinson.

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.

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Photo 3. Adult male light morph “Harlan’s” Red-tailed Hawk (Buteo jamaicensis harlani). Innoko NWR, Alaska. June 2016. Photo copyright Bryce W. Robinson.

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.

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Photo 4. Adult female “Harlan’s” Red-tailed Hawk with nestling. Innoko NWR, Alaska. June 2016. Image copyright Bryce W. Robinson.

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.

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Photo 5. Female dark morph “Harlan’s” Red-tailed Hawk (Buteo jamaicensis harlani). Note the near wholly red tail. Innoko NWR, Alaska. June 2016. Photo copyright Bryce W. Robinson.

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.

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Photo 6. Second-year “Harlan’s” Red-tailed Hawk (Buteo jamaicensis harlani) midway through pre-basic molt. Innoko NWR, Alaska. June 2016. Photo copyright Bryce W. Robinson.

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.

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Photo 7. Adult light morph “Harlan’s” Red-tailed Hawk (Buteo jamaicensis harlani), showing traits suggestive of B. j. abieticola. Anchorage, Alaska. June 2016. Image copyright Bryce W. Robinson.

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.

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Adult dark morph Red-tailed Hawk (Buteo jamaicensis). Subspecies unknown, but this bird resembles what we would expect of a dark morph abieticola, if these exist.  Anchorage, Alaska. June 2016. Image copyright Bryce W. Robinson.

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.

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The Muddy Ruddy

by Bryce W. Robinson

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The Ruddy Duck is a unique character in appearance. They are not all too uncommon in areas I frequent lately, but I always enjoy finding them and watching their behaviors. The Ruddy duck dives for its food. It digs through the mud on the bottom of the freshwaters, returning to the surface after a successful mudding, to look about, swim some distance, and dive again. The fun of  the divers is to see a submersion and watch for the bird to reappear.

I was watching a Ruddy, about its business, in a freshwater estuary of the highly saline Great Salt Lake. As it dove and resurfaced, I began noticing that each time the bird came up, its broad bill was soiled with silt from where it had been feeding. The mud added to an aesthetic I enjoy immensely among diving waterfowl. So often, they resurface with beads of water across their back, and semi-saturated feathers on their face and crown. Their breast often appears glossy. Watching closely always rewards me with a detailed view of textures and details overlooked from quick glances or distant views.

Birding is rewarding on so many levels. I can’t help but respect it all.

 

Red-tailed Hawk- Buteo jamaicensis Consuming Prey

by Bryce W. Robinson

 

I took this video the other day. At the beginning, you can see the bird reject the intestines of the rodent. Everything else is consumed. It is a bit long, but worth a watch. The hawk gets very animated towards the end. It is quite the treat to view, as a great deal of detail is visible.

I wonder about this bird. In the winter, it is difficult to distinguish visitors from residents. This is a unique looking bird. White on the lores, crown, and supercilium is not common amongst Utah’s western Red-tailed Hawks. Perhaps this is a bird from the north country. One cannot be sure, but it is fun to wonder.

Buteo cooperi- A Journey of Mystery Into Ornithological History

by Bryce W. Robinson

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A quick sketch of my interpretation of Buteo cooperi

A few weeks ago my friend Mike called me and asked if I was interested in helping him solve a bit of a mystery he had stumbled upon. A friend of his had found an old ornithology book in a store in Moab, Utah. She was admiring the plates, and came upon one that interested her. It was an illustration of a hawk named Buteo cooperi. She had never heard of any Buteo with the species epithet cooperi. Her curiosity caused her to contact Mike and ask if he had any idea what this bird might be. He had never heard of Buteo cooperi either, but resolved to solve the mystery.

Mike did some research and came up with a reporting of two accounts of this Buteo cooperi. Apparently, in 1855, an ornithologist named J.G. Cooper came upon an interesting hawk in southern California. He shot the hawk, as was the custom of the time, and collected the specimen. He decided the bird was its own species and coined it Buteo cooperi. Mike found this account, as well as an account by the ornithologist Ridgway on the California bird and a second Colorado bird. You can read his account  here. Both accounts hover around the possibility that this bird is somehow related to the Red-tailed Hawk- Buteo jamaicensis, and could possibly be the light phase of the subspecies Harlani. Ridgway reviewed the decision to coin Buteo cooperi as a separate species, however he was confused by the coloration of the primaries, and could not settle upon the identity of the bird. It was left unsettled.

When Mike called me, he had felt that he needed a second opinion and some help with the bird. I of course agreed to help. As I am a true geek when it comes to the world of birds, I thought the journey back into the archives of ornithological history would prove fruitful for my education. And of course it would also be fun. I read the two papers that he sent me describing the bird, and felt that the specimen was likely the light morph of Buteo jamaicensis harlani, the Harlan’s Hawk. Still, to be thorough, I searched further.

I finally found a definitive answer to support my assumptions at the following link.

http://elibrary.unm.edu/sora/Condor/files/issues/v032n05/p0259-p0260.html

This description from a review of the specimen in 1930 gave me the impression without much doubt that the bird known as Buteo cooperi was in fact a light morph Buteo jamaicensis harlani. I felt good about where the mystery came to its end, but for the need to somehow come to an answer of my own, I decided to do some further looking, and it payed off.

I found a link to information regarding a specimen at the Smithsonian in Washington D.C. The specimen is in fact the very bird that J.G. Cooper shot, and collected. You could imagine my excitement at finding that the specimen was still around. You can see the link here.

I decided that the only way for me to come to any conclusion on the birds identity was to see the bird for myself. At the moment, I was not in any position to make a trip to Washington D.C., so I thought I would take a chance at emailing the curators of the museum in hopes that they might send me some photos.

Below, you can see the result of that email. They sent me photos!

 

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It is obvious by these photos that this is indeed a light morph Harlan’s Hawk. I love the white in the crown and nape.  What an adventure. I am super thankful to Mike for including me in the hunt. I would also like to thank those at the Smithsonian for their cooperation and willingness to send me these photos. My curiosity and fascination for the study of birds knows no end, and the history of ornithology is no exception. Let the journey for knowledge continue.