Date: 6/11/19 1:11 pm
From: <t4c1x...>
Subject: [obol] WAAAY out on a limb-long post


Maybe it is time. For nearly four decades I have remained largely silent about my sighting of an unusual bird in the southeast corner of the state. Even now, the report will undoubtedly be met with skepticism in some quarters.

When I was much younger and considerably more adventuresome, in a period spanning four years I visited the Trout Creek Mountains three times: June 12-13, 1979, August 25-26, 1980 and September 6-7, 1982. On the first two visits I felt like we were the only people, other than ranchers, who had been in the Trout Creeks for decades. By the third visit, the increased amount of tire tracks and roadside litter made it obvious the range had been "discovered" by a lot more people.

The Trout Creeks were as fascinating as they were remote. Viewed from the west side, they appear to be relatively barren, but the canyons on the east side contain deep valleys, large aspen groves, many square miles of grass mixed with sage, and great diversity of habitat. Trout Creek is aptly named, because it was astonishingly chock-full of trout. Deer were abundant in the grassy areas. At one time we saw six large Mule Deer bucks in one spot. And the birding was nothing short of phenomenal, particularly during the visit of August, 1980.

In a preface to a description of how phenomenal the birding was, I should mention, that at that time, much of the land in the Trout Creeks was owned by Don Orlando, who lived along the Whitehorse road north of the range. We had obtained permission from him to travel on his property, and we took advantage of it by walking over as much of it as we could in the time available to us.

On that second visit, the phenomenal nature of the birding was enhanced by the weather. Both nights we (a non-birder friend and me) camped in the mountains, a thunderstorm rolled through right after dark. As a result, there was tremendous fallout of night-migrating birds. Just before sunup on both following mornings, the aspens were swarming with migrants. There must have been thousands of them, because it seemed like there were twenty birds in every tree, all rapidly moving about in a maelstrom of activity and color. There were warblers, sparrows, tanagers, buntings, finches and vireos. Most of the warblers were Yellow-rumps, but I did see one male Bay-breasted, which still retained some chocolate color on the head and throat. As soon as the sun peeped over the horizon, the birds were gone. It was the most incredible movement of migrants I have ever seen, or ever expect to see. I think it must have been on a par with the famous fallouts of migrants at Cape May, New Jersey or High Island, Texas.

By mid-afternoon on the 26th, we had worked our way a couple miles north on Mahagony Ridge. Like the creek, it was aptly named, because at that time it contained a sizeable forest of mahogany trees, twelve or more feet in height. After we left that area, we came to one of the most unique habitats I have ever seen. Right out in the middle of the grass and sage was about a three acre spot of solid bedrock. Scattered here and there throughout this area were piles of rounded-off rocks, up to three feet in diameter. They were completely different in shape from the rectangular rocks forming the edges of the mesa. The entire area gave the distinct impression of being an old riverbed, and I have little doubt that is what it actually was.

Since there was no soil on the surface, there was very little vegetation in the entire area. There were some scattered tufts of grass and a very few stunted mahogany trees growing from fissures in the rocks, but nothing more.

But there was a bird, a thrasher in fact, which showed a determined reluctance to leave the area, and a decided preference of running to flying. I observed this bird for about forty five minutes, at distances ranging from five to fifty feet. It was a secretive bird, and made many attempts to stay out of sight. If caught out in the open, it tended to run rapidly for cover, and not infrequently it would hide for a time in the rocks. Then it would pop out again, and run for the cover of another rock. Only once did I see it fly, very low to the ground, in order to cross a wider section of open ground in shorter time.

The bird did not seem to me to be very large. It was a couple inches longer than a Sage Thrasher, but appeared to be of slender build. Its plumage was rather nondescript. Here is the verbatim description I obtained at the time of the sighting: "Entire plumage pale gray, slightly darker on upperparts. Chin and throat slightly paler than rest of underparts, but blending subtle. Tail darker than back, the outer two feathers on each side tipped with grayish white. This mark most visible on bird in flight, although it could be seen on perched bird at very close range on some occasions. Lower belly in some lights appeared to be a light rose pink." The bill was black, a bit longer than the head, but not strongly curved. The eye was entirely dark.

I did not have a field guide with me at the time, but assumed, from the time spent looking at the bird and the description I obtained, I would be able to properly identify it at the next opportunity to check my field guide. I was wrong. As a matter of fact, it was close to twenty years before I came to a satisfactory conclusion as to the identification of the bird.

There were a couple of reasons for this seemingly inexcusable delay. One was a false assumption on my part. I knew that shortly before or after my sighting ( I don’t now recall which), a Curve-billed Thrasher had been reported from Virgin Springs in northern Nevada. It seemed logical, that the Trout Creek bird was likely of that species. Consequently, I attempted to convince myself it was, but I couldn’t. There were too many inconsistencies between the plumage of Curve-billed and the Trout Creek bird. Nevertheless, I kept doggedly trying to find something, which would settle my mind as to the discrepancies. I thought perhaps the dark eye was an age related feature, true of young birds, but found nothing to substantiate that hypothesis. I just could not make the Trout Creek bird fit into the category of a Curve-billed Thrasher.

In April, 1984 I had the opportunity to visit Arizona. While there, I spent some time walking the trails in an undeveloped park just out of Phoenix. I saw Curve-billed, Bendire’s and Crissal Thrashers. None of them resembled the Trout Creek bird. Curve-billed and even Bendire’s struck me as being more robust than the bird in question, and the plumage of both was far off.

Ten years later I traveled to Michigan to visit friends. While there I was able to examine thrasher specimens in the collection of the University of Michigan in Ann Arbor. After studying them, I came to the same conclusion at which I had arrived after seeing live specimens in Arizona. Incredibly, I did not think to examine the skins of species other than Curve-billed or Bendire’s.

The other excuse (if I may call it that) for the delay was that the field guides I owned at the time of the sighting and for some time afterward did not adequately illustrate some important features of thrasher plumage, particularly the pattern of the tail. Most of those illustrations showed Curve-billed and Bendire’s as having a slight amount of white in the corners of the tail, and no pattern at all on the tails of the other species. The gray corners to the tail had been such a striking feature of the Trout Creek bird I basically wrote off the possibility of it being one of the species illustrated in the field guides as having all dark tails. So, the mystery remained unsolved – until ..

Until I bought a Sibley field guide. One of the best features in his guide is that he illustrates every bird in flight. When I came to the pages illustrating the thrashers, there before my eyes was an illustration of one with gray corners to the tail feathers: a LeConte’s Thrasher. I did a double take. Going back to my original notes, I found almost everything checked out: the pale gray coloration, the basically nondescript plumage, the slightly darker upperparts, the darker tail with gray corners, the light pink lower belly (illustrated as light orange on the undertail coverts in Sibley) and the dark eye. The barrenness of the particular habitat in which the bird was found, and its habit of much preferring running to flight also fit LeConte’s Thrasher.

There are two things, which make such an assessment problematic. One, of course, is the range. LeConte’s Thrasher has a rather limited range well south of Oregon, and is not known to have vagrant tendencies. What few extralimital records there are of the species are not far from its known breeding range.

People, of course, can make their own assessments of such things, but I would like to make a few comments of my own. Just because the occurrence of a rare bird in a strange location is unlikely does not mean it is impossible. Some other birds from the same region are also not know for wandering widely, but I figure if a Pyrrhuloxia can show up in Peoria, a Toxostoma lecontei can show up in the Trout Creeks, particularly if it happens to be a dispersing juvenile, which I suspect the bird was. Secondly, the closest point to Oregon where LeConte’s Thrasher is known to be is near Bishop, California. That location is not far from Walker Lane, a natural trough around fifty miles wide, which runs from Death Valley all the way to Goose Lake in Oregon. It could provide a natural corridor from birds traveling north from their known breeding grounds. Speculation, yes, but not unreasonable speculation.

The other problem has to do with the description of the bill on the Trout Creek bird. It was not strongly curved. I have been unable to find any information as to whether or not the bills of young LeConte’s are less developed than the bills of adults. If they are, and if the bird was, as I suspect and as the date of the sighting suggests, an immature bird dispersing from its breeding grounds, the feature would find satisfactory explanation. Furthermore, in some on-line photos of LeConte’s Thrasher, the bill looks only slightly more curved, than that of the Trout Creek bird.

I well understand the skepticism this report will generate. Such well deserved skepticism begs a well deserved question. If the Trout Creek Mountains bird was not a LeConte’s Thrasher, then what was it?



Postscript: The day following the sighting, I stopped in at Malheur National Wildlife headquarters and told C.D. Littlefield what I had seen. He suggested someone collect the bird, but so far as I know he never made any attempt to do so. Small wonder. Mahogany Ridge is a long way from nowhere, even in a land not unfamiliar with distance being judged by looks instead of miles.






 
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