The Tallgrass Prairie Preserve is covered with rocks. Almost everywhere you look you see rocks — some are large boulders, others are small and cover the surface; some protrude out of the ground in regular rows, and others are just scattered about. The stream channels are filled with large and small rocks and often have a rock pavement on the bottoms.
Having spent most of my life pursuing scientific solutions, all these rocks posed questions to me about the geologic structure and history of the area. My conclusions from casual observations were that these rocks I saw were limestone and sandstone. They range in color from light gray to tan with occasional blackish coating. Limestone often has visible fossils. Sandstone is composed of sand grains cemented together. Following my usual pattern when I am faced with a question, I did a little reading on the subject. I found an article on the internet with the title: The Geology of the Tallgrass Prairie Preserve, Osage County, Oklahoma — An Introduction and Field Trip Guide. It was prepared jointly by the Oklahoma Geological Survey and the Nature Conservancy — Oklahoma Chapter. The author was Neil Suneson, and it was published in 2000. This article summarizes the geological information on the preserve and includes a guide for a geological field trip. Follow the link above to the article.
On reading the article, I found that my rock-type conclusions were correct. Suneson states that, along with shale, the rocks of the Tallgrass Prairie Preserve are limestone and sandstone. Shale is rarely seen on the surface because it disintegrates quickly when it is subjected to weathering. On the Preserve, as with most of Oklahoma, the layers of rocks dip to the West, which means that the surface rocks on the west side of the Preserve are younger than those of the east side. On the western side of the Preserve, the rocks are Permian Era (290 to 245 million years old) and on the eastern side Pennsylvanian Era (323 to 290 million years old). All are sedimentary rocks that were laid down as deposits from water as the sea advanced and retreated several times throughout the geologic history of the area — sandstones and shales when the water was shallow and limestones when the water was deep. The nearly horizontal layers of rocks found below the surface and the fossils that are present clearly depict that history.
Suneson states that the surface rocks of the eastern part of the preserve are mostly sandstone and the western part of the preserve are a mixture of limestone and sandstone. The east side with mostly sandstone is part of the Oklahoma Crosstimbers, a vegetation zone composed of scrub forests (Post Oak and Blackjack) that extends southward from the Preserve through central Oklahoma following the thick layers of sandstone of this region. The west side is part of the Flint Hills that extends northward into Kansas.
Another observation is that the eastern part of the preserve has steeper slopes and more relief and is vegetated mostly with Post Oaks and Blackjacks while the western part of the preserve has more gentle slopes and is vegetated mostly with grasses. The rolling terrain was caused by erosion. Suneson states that the tops of the hills are areas that resisted erosion because they are capped with a hard layer of sandstone. Where running water could break through the hard caprock, it carved the valleys. The rock differences created the topographic variety.
The abundance of rocks at or near the surface is one of the reasons that
this land has remained in its original state (or as it was before human
intervention). It just couldn’t be plowed. On one of our several trips to
the prairie together, Jenk Jones quoted an Osage leader who had said that
the Osage land was good land because white man could not put iron thing
into the ground. So having this section of the prairie still in an
original
condition is due at least in part to its geology.
Additional reading on the rocks of the Tallgrass Prairie Preserve can be found in Tallgrass Growing, photos by Harvey Payne and text by Jenk Jones, The Nature Conservancy — Oklahoma Chapter, Kirkpatrick Foundation, Inc.
Sparrows in general are a not very flashy or exciting group of birds. They are usually painted in shades of black, brown and white. The Lark Sparrow is no exception to this rule; however, the Lark Sparrow is the largest of the open country sparrows at 6.5 inches. A good indication that you have spotted a Lark Sparrow is its curious habit of flying to the highest available perch when flushed. It has been my experience that few other open country sparrows react in this manner. They like to fly level with the grasses a short distance, land and run into the dense tangle. In contrast, the Lark Sparrow flies high, lands in a small tree or shrub and surveys its surroundings to see what the excitement was about.
The Lark Sparrow has a rounded tail with prominent white corners. It has a harlequin black, white and chestnut face. The underparts are a bright white marked only by a dark central breast spot. The Lark Sparrow arrives in Osage county in March and stays through July. It is a short distance migrant, spending its winters farther south in the United States and Mexico. The Smith’s Longspur’s sojourn on the Prairie is from January through mid-April, so the stay of these two birds in Osage County overlaps for about six weeks. It is a similarly sized bird at 6.5 inches and the coloration and markings are similar. Two things to remember when distinguishing these birds are: (1) the Smith’s Longspur has a buff chest and a white cheek patch, whereas the Lark Sparrow has a whitish chest and a brown cheek patch and the Smith’s has more white on the tail; (2) the Smith’s Longspur will fly a short distance and dive back into the grass whereas The Lark Sparrow normally flies to a high perch in a tree, shrub or fence rather than diving back into the grass. If you remember these two points you will eliminate the confusion between these two open country birds.
Another curious characteristic to remember about the Lark Sparrow is that it walks when it is foraging on the ground unlike most songbirds who hop as they forage. The Lark sparrow will forage for seeds and insects on the ground or in low trees or shrubs. It tends to concentrate on insects prior to and during the breeding season and will even include grasshoppers in its diet.
The Lark Sparrow favors a variety of open habitats including grasslands, cultivated fields and residential areas. Burning is usually beneficial to this species as long as the burns are not too hot and leave areas of small trees and shrub in the field. They need about 10-percent brush cover to remain in the burned area. Burns conducted in early March before the arrival of the Lark Sparrows are the most beneficial types of burn. Lark Sparrows are a very adaptive species. In cropland, hay land, idle areas, pasture and tame habitats they choose a variety of nest locations. In cropland and suburban habitats they choose to nest in low trees and shrubs, while in pastures and grasslands you will find the majority of the nests on the ground.
The Lark Sparrow builds a nest cup of grasses and small twigs, lined with finer grasses and sometimes hair. The nest can be placed in a small shrub or tree or on the ground next to a forbs or grass.
It will lay 3 to 5 creamy white eggs with black or lilac spots and scrawls around the larger end. The female will incubate the eggs for 11 to 12 days and the young fledge at 9 to 12 days. The ground nests of the Lark Sparrow are heavily parasitized by the Brown-headed Cowbird. Studies have shown that twice as many ground nests are parasitized as above ground nests and this could be the reason for the two different nesting strategies. The nesting seasons runs from April through July. The short time from egg laying to fledging gives the Lark Sparrow an opportunity to raise at least two broods during the nesting season.
The Lark Sparrow is a common summer resident across Oklahoma. During the summer as I drive the Bison loop, by the Blackland Pens, I often flush Lark Sparrows in the high grass along the roads. True to form they will flush and land on the road-side barbed wire fence, sitting on the top strand looking at me.
If you enjoy birding from the front porch of the Visitor’s Center don’t assume the sparrows foraging in the cut grass are House Sparrows. Take a minute to look at them through binoculars and you might be surprised to see the clown like face of a Lark Sparrow.
Here we provide some links to other places worth visiting.
Here is the latitude and longitude of the Visitor’s Center that you can give to visitors for entry into their GPS navigation device.
The manufacturer’s instructions for cleaning the touch-screen recommend use of a soft dry cloth only. This proved inadequate for smeared fingerprints. Soft-paper kitchen towels work well, slightly damp with a small drop of soft handsoap. Application of a dry kichen towel removes any residual moisture.
Over time, a matter of several weeks continuous operation, I have noticed that calibration of the touch-screen drifts away from the initial set-point. If you notice that the cursor isn’t under your finger when you touch the screen then restart the kiosk by unplugging it from the wall, waiting a few moments and then re-inserting the power plug. It will restart and recalibrate.
This link points to the complete Kiosk Maintenance Manual.
Some printed back issues of the Docent Newsletter, to February 2009, can be found in the two green and one blue-black zip-binders, stored in the Perspex rack by the file cabinet in the office of the Visitor’s Center.
All back issues are available electronically via the links shown below. All newsletters prior to December 2007 are available in Portable Document Format (PDF), which means that you will need Adobe Reader installed on your computer to read these files. All newsletters from December 2007 onwards are in HTML format that is easily read using your web-browser.
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2012—January
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2011—January
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2010—January
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2008—January
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2000—January
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1999—January
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December—1995
This persistent index of selected topics should make finding articles of interest easier. The list will grow as I move further into the past and it will grow as I add interesting topics from each new newsletter. Iris McPherson lent me the paper copies of the newsletter from the very early years of the docent program; I ran them through a scanner equipped with a document feeder, saving them as PDF files, then added them to Back Issues section above. Let me know of any dead links that you discover. Also, please lend me any paper copies of the newsletter that are missing so that I can scan and add them to the list of back issues.
Deadline for submission of articles for inclusion in the newsletter is the 10th of each month. Publication date is on the 15th. All docents, Nature Conservancy staff, university scientists, philosophers, and historians are welcome to submit articles and pictures about the various preserves in Oklahoma, but of course the Tallgrass Prairie Preserve in particular.