A studio for bird study

Tag: swainsoni

September 18, 2013

The Benefits of Photography for Mapping Avian Movements

by Bryce W. Robinson

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Above is a photo of an immature light morph Swainson’s Hawk that I took on the 7th of September, 2013 at the Goshutes Raptor Migration Sight in eastern Nevada. Notice the red band on the birds left leg. I’ve cropped the image a great deal, but below I’ve enlarged the section of the image to show the band in greater detail. At this resolution, the image becomes pixelated, which is unfortunate.

SWHA MAGI contacted the BBL in hopes of tracking down someone that might recognize the band. I am so very grateful for their organization, as they quickly sent out emails asking those they have permitted for color banding SWHA. Within a day or two, I had a hit.

A man name Chris Briggs contacted me and gave his firm assurance that this bird was a bird he had banded earlier this year as a nestling. He mentioned his use of special characters such as the obvious < symbol on this birds color band. He thought that the other character on the right was either an 8 or a 9. One cannot be too certain, but he did assure me that the band was certainly his.

As the birds age was apparent from its plumage, I was really interested in where the bird originated. Chris informed me that this bird was banded as a nestling near Macdoel, California, a town near the northern border just south of Klamath Falls, OR. He sent me the photo below.

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Photo courtesy of Chris Vennum

How exciting! It is nearly certain that this bird is the same bird as the bird I photographed in Nevada. I am so thankful that the organization exists such that a photographer can capture a photo of a bird with a band, and if the band is legible, can track that very same bird to the place that it was banded, without ever trapping the bird. The invasiveness of trapping hawks is curbed with the advent of the camera! Revolutionary….

Well, my question is then why are we as raptor researchers, or ornithologists as a whole not employing this technique more often? Some may state the added detriment of more bands is not worth while, and I do not discount this contention. However, how much more detrimental will one color band be to an already banded raptor? It is a discussion worth having, because with the amount of folks armed with cameras today, we could find ourselves with a lot more re-sight records, and a better understanding of spatial ecology in particular species.

I’d like to include another recent instance for emphasis. A few months ago, my friend and obscenely talented photographer Ron Dudley photographed a young Prairie Falcon in Montana. It happened to have a color band, and he was able to track down where the bird was banded. As it happened, his bird was also from California. You can read the story in detail on his blog.

How peculiar, this bird that fledged from its nest, and for whatever reason did not disperse directly south, but in a somewhat north east direction. North east enough that it passed by the Goshutes in early September on its way south. In my own personal study, I’ve learned that this non southward directionality of post fledging dispersal is something many people tracking birds of prey are seeing. The old north to south paradigm is becoming a bit more complicated than initially thought, and young birds seen traveling south on their fall migration, aren’t necessarily birds fledged from the north.

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August 2, 2012

A Bounty of Summer Buteos

by Bryce W. Robinson

“Intermediate” morph Swainson’s Hawk- Buteo swainsoni.

Yesterday I ventured out to find some raptors with Jerry. We found found an area covered with “summering” Buteos, in densities unprecedented in my young and limited experience with the raptor world. I am enthralled with the ecology of wintering birds of prey, primarily for the interspecies interactions that occur in high density hunting grounds. Yesterday, I found the same densities and something of the same diversity. I have never seen so many Swainson’s Hawks and Ferruginous Hawks in one area. I was very delighted to observe numerous interactions between each species. Surprisingly, the bully seemed to be the Swainson’s Hawks. The Ferruginous didn’t seem to mind the Swainson’s, but a few times I observed Red-tailed Hawks being bullied by the summer migrants.

One particular incident made my day, and provided me with a glimpse of something I’ve never seen, and actually was unaware existed. A Swainson’s hawk and Red-tailed Hawk soared together rather high in the noon sky. The Swainson’s began buzzing the Red-tailed Hawk, resulting in some dramatic arial displays as they twisted to push the other away. Finally the climax of the interaction came when the two birds latched talons and began tumbling through the air. After multiple rolls, the birds broke, sending the Red-tailed Hawk fleeing from the scene. I have seen tumbling between Red-tailed Hawks as they engage in talon clasping to reinforce pair bonds, but never as an aggressive territorial interaction between two different species. The birds were some distance away, so the photos I came away with are not ideal, but interesting nonetheless.

Red-tailed Hawk (top) and Swainson’s Hawk (bottom) engaged in an aggressive tumbling interaction.

Birds blanketed the valley. Every other telephone pole supported a perching buteo, and the irrigation lines were covered with ravens and buteos as well. On one particular raven-less wheel line I counted eleven birds, comprised evenly of Swainson’s and Ferruginous Hawks. Not only was there interspecies diversity, but within each species, variation in plumage was present as well. I love dark morph Ferruginous Hawks, and a few flew around. These birds were leery of our intrusion, so I was unable to get any good photographs. I did photograph a very interesting adult Ferruginous. I assume it to be something like a rufous morph, perhaps in the midst of body molt, however its present state gave it a tiger like appearance. This is by far the most spectacular Ferruginous I have found to date.

“Tiger” Ferruginous Hawk- Buteo regalis

“Tiger” Ferruginous Hawk- Buteo regalis

I’m a plumage enthusiast when it comes to buteos, so this day was all that I could hope for. The diversity in Swainson’s Hawks was a treat. These birds vary immensely. I found the typical light morph birds, rufous birds, dark birds, and even some that exhibit mottling, perhaps intergrades between the morphs or showing body molt. I remember one particular bird near the end of the day that was nearly black, but it had extensive mottling not unlike a dark Harlan’s. Regrettably, I failed in my attempts to photograph this bird.

Intermediate Swainson’s Hawk- Buteo swainsoni

Light morph Swainson’s Hawk- Buteo swainsoni

It was surprising to find an area so devoid, relatively, of Red-tailed Hawks. There were few hanging about, most likely due to the attention they received from the gangs of Swainson’s Hawks. Still, we found a few birds and were able to come away with some photos.

Light morph Western Red-tailed Hawk- Buteo jamaicensis calurus

Juvenile light morph Western Red-tailed Hawk- Buteo jamaicensis calurus

The above birds was found sitting in a tree with a nest, and another young bird. Given their behavior, Jerry thought this bird to be very young, which is surprising given that most birds fledge early in the year. A late nest is peculiar, but it is highly probable that these birds have only recently taken to the air.

I have a few qualms about the photos I have shared. Although they are the best I have taken thus far, I failed to capture the catch light in most images, and for whatever reason many of the wings are blurred. I resolve to figure out how these problems can be corrected, but I feel great about my successes thus far. My homelessness and beatnik birding lifestyle continues for little longer, but in the small amount of time much will be chronicled. Let the good times soar.

 

 

 

 

 

 

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July 27, 2012

A New Stride in My Study of Raptors Through the Lens

by Bryce W. Robinson

Swainson’s Hawk- Buteo swainsoni

And finally it has happened. An update from the Beatnik Birder, and a new development making a lengthy stride in fulfilling his study. After too long, I have upgraded my camera equipment. My lapse in posting of late is attributed to many happenings in my life. I have been birding, or out working with owls, but I have not had the time, drive, or energy to share my experiences. I have felt the void this has caused, and I am confident that the lull has passed.

The new drive comes from my new camera, the Canon 7D. Coupled with the camera, I purchased a 300mm f/4.0 telephoto lens and a 1.4x teleconverter. I’ve taken the camera out a few times already, and am working to learn all that I can as quickly as possible. I figure the amount of time I invest will be directly related to my success. I must now go to work. The camera will not only create loads of fun and play, but will become and invaluable tool for the research I’d like to accomplish on the world of birds.

I knew as soon as the camera came that I had a subject I was extremely interested in capturing. A few weeks ago, Mitch Tall and I went west along I-80 to see what we might find. We came upon a large number of Swainson’s Hawks hunting the pastures to the north of the highway. I was very surprised at the number of birds present in such a small area. Among the light, dark, and juvenile Swainson’s was also a young Ferruginous Hawk. This bird was the first Ferruginous I had ever seen in the Salt Lake Valley. I was pleasantly surprised, to say the least.

Now armed with my new equipment, I thought it fruitful to return to the spot in hopes of finding the same number of birds as before. The night before I had found a group of eight Swainson’s on a thirty acre plot near my parents. A trend perhaps, and future investigation will add to my ideas about migrant grouping in hunting grounds for raptors. I was certain I would come away with some great shots if the birds were again hunting the fields along the interstate.

When Mitch and I made it to the area where the group had been, we were a bit disappointed to find only a few birds perched and in the air, scattered much farther than before. Two young Red-tailed Hawks circled above, but had risen on thermals a bit too high to get a spectacular photo. Still reviewing the shots I did come away with, I was tickled and impressed with my new gear.

Juvenile Light Morph Western Red-tailed Hawk- Buteo jamaicensis calurus

I was lucky enough to find a few members of my target species. Most of the birds were circling far from the road, far out of range of my camera. Finally we had luck, coming upon a perched Swainson’s Hawk only two hundred meters or so from the road. Far enough to feel comfortable with our intrusion, but close enough for some worthwhile photography.

Swainson’s Hawk- Buteo swainsoni

After watching the bird for some time, and taking many many photos, we were fortunate enough to watch as the bird lit off pole #36. I missed the chance at photographing the bird as it left the post, but I did catch him gliding feet above the ground.

Topside of gliding Swainson’s Hawk, showing some apparent body and flight feather molt.

After seeing the bird fly, and land on a post farther down the road, I could tell that this bird was molting. From the photo of the bird pulling up just before landing on the post, you can see that P1-5 are fresh new feathers, and many of the outer retrices are actively growing in. Also, from the mottled look of the scapulars and upper wing coverts, it is apparent that the bird is undergoing a body molt as well. I reviewed some photos of the bird as it flew, and I a under the impression that this bird is molting into its first adult plumage. I love this stuff. I haven’t sent any of these to Jerry Liguori for conformation or review, but I’ll be sure to. After which, I will correct any mistakes I made, or even elaborate on what can be told from this bird.

Swainson’s Hawk- Buteo swainsoni. Note the remige and retrix molt, as well as the body molt of the upper wing coverts. The darker wing feathers, P1-5 are newly grown feathers, as well as the central retrices.

My main fascination with Buteos is the diversity in their plumage. Using my camera for a recording tool, I’d like to add to the work of Jerry Liguori in documenting the vast varieties that present themselves in these winged predators. My images at the moment are not near the quality they could be. I want to correct that. I know they won’t reach the Ron Dudley quality, but I will do my best.

Here is to the future of my study. Finally my photography will progress. Let’s hope the birds cooperate.

Juvenile Swainson’s Hawk- Buteo Swainsoni

 

 

 

 

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