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January 16, 2013

Buteo cooperi- A Journey of Mystery Into Ornithological History

by Bryce W. Robinson

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!

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.

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November 10, 2012

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.

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January 27, 2012

Illustrating Light Morph Harlan’s on the Wing

by Bryce W. Robinson

Light morph Harlan's Red-tailed Hawks- Buteo jamaicensis harlani, in flight

Embracing my extreme fixation with Harlan’s of late, I decided to devote my free time today to illustrating a bird I am very unfamiliar with. I have only seen one light morph Harlan’s Hawk in the field, and I see that as a problem. To learn the bird better, I referenced an article written by Jerry Liguori and Brian Sullivan, detailing the plumage characteristics of Harlan’s Hawks in detail. An extension of the article provided me with numerous photographs to utilize in putting together my interpretation of a light morph bird.

Illustrating raptors on the wing is a test for me. Proportion is perhaps the most important aspect to creating a natural and realistic looking bird. Hawks in the air create an image of deep detail, and it becomes a challenge to lay out the detail and form to present a realistic flying bird. I painted two birds, which are actually meant to be one bird, shown at two angles common to the hawk watcher.

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January 15, 2012

Falling Into a Red-tailed Fascination, With a Harlan’s Twist

by Bryce W. Robinson

Juvenile "Harlan's" Red-tailed Hawk- Buteo jamaicensis harlani

I rarely begin a post with a picture, however, I would like to pay tribute to one of the most remarkable creatures to occupy the sky. For reasons truly unexplainable, I find myself fascinated with the varieties of the Red-tailed Hawk, particularly and most intensely, the Harlan’s. The striking plumage and variable tail patterns certainly seem to be the most fascinating aspect of the Harlan’s. Perhaps it is the little known aspects of the birds great north breeding ecology, and the overlap with other Red-tailed strains creating intergrades and even more peculiar and strange forms of this relatively common species. I find the Red-tailed world intriguing on multiple levels, and I have made the goal of a lifetime study of the bird. In my search to specialize for my graduate work, I do at the moment believe I have found my candidate.

I spent the other day photographing birds with Jerry Liguori once again. Of course he lent me his equipment for more photography fun. I still can’t put a finger on why he would be willing to do so, other than his kindness. So I must admit, this entire post is all due to Jerry’s kindness, and I would not have been able to get any images near the quality of what is shown without his help.

Jerry has studied raptors for years. He also has a keen interest in the Red-tailed Hawk. He has written many articles on Red-tailed variants like the Harlan’s and the Krider’s, and has shared a few with me. I have gained much satisfaction in browsing through a number of Harlan’s tail shots that he sent me, illustrating the vast variety that exists among these birds. I actually blame Jerry for feeding my obsession with the bird. Now he has to put up with my endless intrigue as I pick his brain for answers regarding Harlan’s.

On this outing we went to an area of particular popularity due to the high density of wintering raptors. As any Utah birder likely knows, the area I speak of is the basin directly south of the point of the mountain. The birds detailed in this post were all photographed at this basin. Keep in mind that I stayed in place for a few hours, and the amount of birds featured in this post occupy the area around the basin, which is little more than a square mile. Wintering ecology is an amazing thing, as normally territorial birds put up with others, not even of the same species, and share the resources at hand.

This year, multiple reports of Harlan’s Hawks at the point have hit the hotlines. I had visited the area in November, and saw a Harlan’s, but the soaring raptor was much too high for any reasonable photography. On this day with Jerry, my luck changed. We had a Harlan’s fly in close to provide me the opportunity at my first close range photo shoot of my favorite flyer of late.

This young Harlan’s is a favorite of another Utah birder. Tim Avery constantly posts his images of the point of the mountain Harlan’s. He met up with us after a while and was right alongside me when the bird came in for the shot. According to Tim, the photos he took were the best Harlan’s he has to date. I must admit, I like his shots better than mine.

The young Harlan’s was actually not the most exciting bird of the day. As Jerry and I drove south on the freeway before reaching the basin, I told him of my lack in confidence for identifying a light-morph Harlan’s, and how much I would love to see one in the field. I feel that some of Jerry’s self proclaimed luck then rubbed off on me, or perhaps I was just lucky enough to be with him, but one of the first birds we saw as we came to the basin was in fact an adult light-morph Harlan’s. Regrettably our luck only went so far, and I never reached a close distance in order to photograph the bird. Jerry, with his great lens, actually caught the bird from behind as it landed on a post. The tail was perfectly spread, exposing a silver-ish base fading to a nice reddish tone. A few feathers even had some slight banding. A perfect Harlan’s tail, and a beautiful bird.

There were a total of three Harlan’s at the basin that day. I photographed two, both of which were juveniles. The second bird displays perfectly an aspect of my fascination. The white breast is peculiar, and sets it apart from the other young bird we saw later. I love the variation, and I can’t get enough of studying these birds.

Juvenile "Harlan's" Red-tailed Hawk with a white breast

It was delightful to watch the numerous birds interact with each other. Near the peak of the mountain five birds flew, toying with one another. As it appeared, the birds seemed to be enjoying the sun, with full crops and playful spirits. As I watched, I noticed that one of the birds was in fact a Rough-legged Hawk. The interaction did not appear aggressive, which made the sight much more peculiar. Seeing the Buteo’s fly together reminded me of a bird found last year in the mid-west. It appeared to be a hybrid between a Red-tailed Hawk and a Rough-legged. When breeding season comes, and birds have trouble finding a mate, it can happen that two birds of different species pair up in desperation to procreate. I have even heard of Ferruginous Red-tailed Hawk hybrids.

One of the reasons I am so intrigued by Buteo jamaicensis is the variable plumages that exist. The Western Red-tailed Hawks that were present provided a great look at the variety present in even the more common strain. From juvenile to typical adult, all were there. I would have liked close up photos of all of the birds that day, but birds are only so cooperative, or better said, I am only lucky to a point. Still, I came away with great shots of a number of birds.

Rufous morph Western Red-tailed Hawk

Adult Western Red-tailed Hawk with a white throat

Typical adult Western Red-tailed Hawk

Jerry mentioned an interesting point after seeing an adult western bird with a white throat. Apparently some years back it was common knowledge that western RT’s lacked a white throat, like the typical bird above. This fact was cited in many guide books for the hawks of America. I found this interesting because it illustrates a point that Jerry has really tried to engrain in me, or so it seems. Facts about birds depend upon research, some research more thorough than others. We as birders, or those enthralled enough to give a damn about the particulars, need to be comfortable with getting things wrong, making mistakes, information changing, and especially saying “I don’t know”, from time to time. I respect Jerry’s humility, and his concern for passing that on to me and others who share his passion.

The fact is that with a bird so diverse in plumage as the Red-tailed Hawk, there is going to be some overlap and interbreeding between regional “subspecies”. What results are birds that show characteristics of one strain, but overall resemble another. I found a bird a few weeks back that was a dark morph western Red-Tailed Hawk, yet it had a heavily banded tail that faded from a cream color at its base to a nice orange at the terminal end. At first glance I was excited at the possibility of a Harlan’s, however when I reviewed my photos, I found the bird to be a nice chocolate brown with rufous highlighting. After consulting Jerry, I learned of the importance of leaving some birds a mystery. The bird could have been an intergrade of some sort, or something else more mysterious and exciting. For now I have no conclusion, but I have come to terms with that and moved along. In the future, I may find another bird that shares the same traits, and may be armed with the knowledge and resources to discover where the bird is from and why it is so peculiar.

Juvenile light morph Western Red-tailed Hawk

Juvenile light morph Western Red-tailed Hawk. Note the light colored eye typical of a young bird.

Juvenile light morph Western Red-tailed Hawk

It was nice to see a variety of Red-tailed Hawks, but what made the day even better was when the Roughies were thrown into the mix. Because I conduct winter raptor surveys, I find myself with plenty of opportunities to photograph these arctic birds, but with Jerry’s help, I believe I came a way with my best photos to date of Buteo lagopus. They are at least in a close tie with those photographed last week using the same camera and lens.

Juvenile Rough-legged Hawk- Buteo lagopus

It seems that I only find Juvenile Rough-legged Hawks this year. What that fact is attributed to I can only wonder, but perhaps it is tied to wintering ecology, perhaps not. While we watched two Rough-legged Hawks soar together, Jerry and I heard the high pitch call of the birds. This was the first time the call of Buteo lagopus settled upon my ears. I did not take it for granted, and I will not forget the sound.

Juvenile Rough-legged Hawk

Although the point of the mountain is frequented with large, loud, and stinking trucks, it is a special place to gain a glimpse into the wild world. It stands as an inevitability that the area will soon be crowded with humanity, and there will no longer be a place for these wintering birds. They will undoubtedly find fortress someplace else, and we birders will follow. Still, how wonderful it would be to see these birds respected, and their winter home set aside from the expanding suffocation of the human world. I see no reality in the idea, as Utah County continues to grow faster than an adolescent boy, but may the seed be planted and pondered on. If you love raptors, make a point to visit this area. If you are respectful of the birds, and the truck drivers that pass, you will certainly have the best day of raptor watching you could ever ask for.

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Tag: harlani

by Bryce W. Robinson

by Bryce W. Robinson

by Bryce W. Robinson

by Bryce W. Robinson