Ornithologi

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Tag: harlan’s

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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Peculiar Plumage of the Harlan’s Hawk

by Bryce W. Robinson

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I found this interesting Harlan’s Hawk today in Hagerman, Idaho. It’s overall plumage left me thinking about Harlan’s ID. I’ve heard many people describe the “distinguishing” characteristics of the Harlan’s Hawk, but I’m always left confused as most of the Harlan’s I’ve seen don’t quite fit the mold they describe. I only know of a handful of people that can properly articulate why a bird is a Harlan’s, or not. In fact, I don’t include myself in that small list. I can recognize the subspecies, but putting that recognition into words is challenging. I believe this is due to the extreme variation in these hawks.

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The white lores and flecking against a dark background on this bird are the only part of the body plumage that tips the filter for Harlan’s. It is not the deep black that everyone describes for the subspecies, nor is it highly contrasting. To be clear, this bird is very dark, but I’ve seen many Calurus that are highly melanistic, with deep dark brown bodies, even with light markings on the breast not unlike this bird. Many of the Harlan’s in Alaska and the Yukon Territory that I saw this past summer were soft brown, not at all high contrasting in plumage. This variability causes some confusion. So what makes a Harlan’s? As with all bird Identification, the ability to recognize a bird comes with study, exposure, and the overall impression of the bird. I have always compared bird identification to facial recognition, where multiple factors contribute to a recognizable image, without any cognizant processing. I leave the breakdown of what specific factors contribute to Harlan’s identification to the true experts, like J. Liguori.

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At times, there are single clinching factors that seal the deal in bird ID. For the Harlan’s, it is the iconic tail, the one mysterious trait that causes we the birder so much awe and admiration. But, I’ve seen Harlan’s with red, banded tails. Most of the birds I saw in the north last summer had extensive red in the tail. The Harlan’s tail can often be misleading. This fact, coupled with the variation in body plumage leads to the point of considering every bird as a whole.

The bizarre tail of this bird is fascinating. The central feathers are half ghostly silver, and half solid dark. The others are irregularly banded and spotted against a background of soft reddish tones reminiscent of its specific designation. After encountering this bird, I’m left with one question: Are any two Harlan’s alike?

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.

 

Differentiating Immature Dark Western Red-tailed Hawks from Immature Dark Harlan’s- A First-hand Experience

by Bryce W. Robinson

My time at the Goshutes Raptor Migration sight has come to a close. Never have I been witness to the magnitude and diversity that I observed in the three months that I lived on the nine thousand foot island in the sky. I came away with a large collection of spectacular photos far surpassing, in quality and content, anything I have ever gathered. Even more, I came away with a great understanding and appreciation for the phenomenon of the fall raptor migration. Field work is immersive in nature. The opportunity to learn and magnify my study in this situation is truly unmatched.

I find my interest intensely involved in the genus Buteo.  Specifically, I am enamored by the polymorphism present in this group. Of these birds, none matches the diversity and allure of the Red-tailed Hawk. The Harlan’s Hawk is quite possibly my favorite bird at the moment. I was obsessive about analyzing every Red-tailed Hawk that passed. Finally, near the end of October, I began seeing the birds of the great north. The banding station was hard at work, capturing and banding all that they could. Every morning I gave them my good luck speech about the inevitability of catching a Harlan’s on that day. Finally, they came through, trapping a dark juvenile Harlan’s Red-tailed Hawk.

Luck seemed to be on my side that day. I spent the majority of the season bothering the banders for pictures to document the diversity of the species. Earlier, hours before the Harlan’s was trapped, they caught a beautiful dark western bird. I was able to get photos of this bird. The result is my ability to show, with photos, the differences between the immature dark Harlan’s, and the immature dark Western Red-tailed Hawk.

I will first introduce and discuss the dark immature Buteo jamaicensis calurus:

Immature Dark Western Red-tailed Hawk- Buteo jamaicensis calurus

It is rare to find a solid chocolate immature Western. This bird is a nice, almost solid bird, however there is still a somewhat mottled appearance on the breast and wing linings. Dark western birds are a beautiful chocolate brown. On dark birds, the upper-tail coverts appear the same as the color of the scapulars and mantle. They do not have the contrast of the whitish upper-tail coverts that a light morph usually has. Sadly, this photo does not adequately display this feature. Of course most immatures have a heavily banded tail that is not the indicative brick red of adults, and they possess the obvious pale primaries giving the appearance of what is referred to as wing windows. The tail often reflects the color morph of the bird, as seen in this bird, having a color that matches the dark solid brown of the body. It is hard not to get too in-depth discussing color morphs of the Red-tailed Hawk. As this is not a discussion on the particulars of each morph, I will discuss the important features to contrast with those of the Harlan’s.

It is important to note that the features I discuss are not always reflected in identifying these birds. As diverse as the Red-tailed Hawk is, it often lacks or reflects certain traits that may throw ones identification into a confusing headache. As in most bird identification, it is necessary to incorporate many factors into an I.D.

For the dark immature western, first note the solid color of the upper-wing coverts, scapulars, and mantle. Also, the head of this bird lacks any mottling, or white markings. Pay particular attention to the area around the eye. As seen in the front view photo, the remiges are banded. The banding is not in heavy contrast with the general color of the wing. This factor is also present on the tail. One factor in contrast with an immature Harlan’s Hawk are the dark emarginated outer primaries. In most Harlan’s, these primaries are banded. I recently learned from Jerry Liguori that this feature is usually only reflected in immature birds. Adult Harlan’s often have solid outer primaries, much like western birds.

Here is the dark immature Harlan’s Red-tailed Hawk- Buteo jamaicensis harlani:

Immature Dark Harlan’s Red-tailed Hawk- Buteo jamaicensis harlani

Separated by the text from discussing the western, it might seem difficult to truly compare the two. Below I have included some comparison photos that can be referenced following the discussion. For now, pay attention to the factors of each bird exclusively. Getting to know the face image of a bird, rather than the nit-picky particulars of individual characteristics will better aid one in identification.

First, Notice the banding on the emarginated primaries of this bird. It is obvious on the front view of the bird, not so much on the backside. Although still a dark brown, this bird is obviously highly melanistic. Harlan’s are often severely dark, even black. This bird is not as dark as some, but it is obviously darker than the chocolate color of the western. The physiological reasons for this are extremely interesting, but for another discussion.

The most obvious feature of this bird, in conjunction with the dark coloration, is the presence of mottling across the body of the bird. This creates a bird of high contrast, which is a feature that might possibly be the reason for my addiction to the aesthetic of this Alaskan wanderer. The mottling is present on the breast, belly, and wing lining of this bird, however, this feature is not exclusive to the Harlan’s. The area to focus on in relation to mottling is the backside of the bird. Notice the heavy mottling present on the upper-wing coverts, scapulars, and mantle. This feature adds to the other factors that make the bird a Harlan’s. Also, notice the presence of white on the face and crown.

I note in the video below that the tail is heavily banded, and the presence of the contrasting white and dark in the tail is unique. These factors do not necessarily add to the identification of a Harlan’s, but it is interesting to note. The tail of the Harlan’s is quite different from the Western. The bands are thicker, and contrast more with the coloration of the rest of the tail. Take the time to see the bird in the video. I briefly discuss all the factors that make the bird a Harlan’s, but the video is really valuable to present the bird in a comprehensive way.

The following photos illustrate a visual to aid in intellectualizing the differences between the dark immature Harlan’s and Western.

Dark Western(top) and Dark Harlan’s(bottom) bottom-side

Dark Western(top) and Dark Harlan’s(bottom) topside

The experience I had this season left me with some impressions and ideas in relation to the Red-tailed Hawk. Much discussion and disagreement is present in the raptor world in relation to the status of the Harlan’s. I have some insight into the issue, provided by exposure to the number of birds I observed this fall, coupled with conversation, and personal study of the bird.

The plumage diversity present in the species Buteo jamaicensis is vast. I observed that the birds of the desert of southern California appear to have plumage differences from those that I observe in the great basin. Also, across the course of the season I documented through photography, the differences in the birds that traveled past the migration sight. I can say, through personal experience and observation, that there is so much diversity in the species that it becomes difficult to differentiate morphs, and at times, even supposed subspecies. The debate in the bird world in regards to the Harlan’s is whether or not it deserves a status as a separate species. I feel that the debate is arbitrary given the knowledge we have about these northern birds.

I even question the status of subspecies in regards to the Harlan’s. The parameters that factor into substantiating subspecies status are particular, however it is my impression that there is not enough known about the breeding ecology of the Harlan’s Hawk to definitively term it a subspecies. Perhaps the Harlan’s is a color morph, an exemplification of variation in plumage, not as geographically tied as we believe.

It ultimately comes down to my lack of knowledge and really, the lack of the collective knowledge of the raptor community. What needs to be done is a comprehensive study, documenting the movements and breeding ecology of Harlan’s Hawks. Through a well crafted scientific study, we can once and for all discover the knowledge that will lift us past what is now only a discussion in speculation.