By Antonio Del Valle
Sunrises over the tallgrass praire were a wondrous daily event to behold while surveying at Nachusa Grasslands.
This summer, as part of my graduate research project at Northern Illinois University, I had the opportunity of studying some of the many bird species that call Nachusa Grasslands home. Luckily, surveying birds is an activity that you can do by yourself, which was a key factor in being able to safely conduct my research project in the midst of a global pandemic.
The focus of my research is to determine how birds that breed on the prairie are impacted by some of the large scale disturbances on the prairie landscape—mainly bison herbivory and prescribed fire. Different bird species prefer different types of prairie. Species such as killdeer (Charadrius vociferous) and upland sandpiper (Bartramia longicauda) prefer shorter prairies that, at Nachusa, are maintained through the eating of plants by bison and frequent prescribed fires. In contrast, species such as Henslow’s sparrow (Centronyx henslowii) and sedge wren (Cistothorus platensis) prefer dense, tall prairies that are maintained through infrequent disturbances.
A figure describing the relationship between different grassland bird species presence and months since a disturbance event has occurred on the prairie.
Grassland birds are a suite of species that specialize in using prairie habitat as their preferred place to breed and raise young. These species are of particular interest to me because grassland birds have experienced drastic population declines. A recent paper published in Science shows just how serious this decline has been.
Bird populations in North America have declined by three billion individuals since 1970. Grassland birds in particular have declined more than any other group of birds.
But it is not all doom and gloom for these grassland birds. Thanks to the hard work put into the restoration, management, and conservation of the tallgrass prairie habitat at Nachusa Grasslands, there are bountiful places for these types of birds to breed during the summer. My research aims to help us understand more about these declining species. Preserves such as Nachusa Grasslands give me an opportunity to observe them in areas where they are still relatively prevalent.
High quality prairie restorations take a lot of hard work but provide great habitat for many declining and rare plants and animals.
A typical morning of surveying birds starts out by waking up well before sunrise. I set my schedule to arrive to Nachusa around 5:30 AM in order to start surveying during peak bird activity. Coming prepared with coffee and waterproof clothes were key factors in staying awake and dry while traversing the dew-soaked prairie. Upon arriving to a survey point at the preserve, I begin surveying birds via sight with my binoculars, as well as by sound. I record all of the birds I see and hear into my field notepad for five minutes. While surveying, I record the number of individuals of each species, estimate their distance from me, and record any breeding behaviors that are displayed. Surveying in this systematic fashion allows me to look at the data later and compare what birds were seen in what areas, how many were present, and whether I can confirm that they were breeding (according to eBird’s breeding bird behavior codes). Additionally, this format allows me to compare my data to other data sets across different years and potentially different preserves/sites.
The depth of the thatch layer covering the ground is measured by using a ruler. This layer of dead plant material is important for certain species that require cover.
In addition to surveying birds, I also survey vegetation and bison density through dung counts. Vegetation surveys involve measuring vegetation height, thickness of thatch layer, and percent cover of plant species. These measurements give me quantitative values to describe the vegetation structure within different areas of the preserve. Bison density is calculated through systematically counting units of dung at my survey locations. Looking at bison density in different areas of the preserve can help show where bison are spending most of their time (and eating more plants).
One of my favorite birds to observe this summer was the Henslow’s sparrow. This secretive sparrow is rarely seen on the prairie, as it spends most of its summer down low in the grasses and only pops up once in a while when singing or flying. The Henslow’s sparrow song is unique as well. Cornell University’s All About Birds online field guide describes it as the simplest and shortest song of any North American bird, and to me it sounds like a faint hiccup. These sparrows have a greenish wash on their face and fine streaks on their flanks, which help to distinguish them visually from other sparrow species if you have the pleasure of catching a glimpse of them. They, along with many of the other grassland breeding birds, are now on their way back to their overwintering grounds in Central and South America. The prairies will be noticeably quieter until they begin to return in the spring again.
I’m looking forward to analyzing the data collected this summer and preparing for next year’s field season over the next few months. I hope that my research can help provide knowledge to aid in the continued conservation of these grassland bird species. Nachusa Grasslands is a wonderful place to observe these birds and many other plants and animals in their native habitat.
Citations & Resources:
Fuhlendorf, S.D., et al. (2009). Pyric herbivory: Rewilding landscapes through the recoupling of fire and grazing. Conservation Biology 23:588–598.
Rosenberg, K.V., et al. (2019). Decline of the North American Avifauna. Science 366(6461):120-124.
Tony’s ongoing graduate research is supported by the following sources:
By Susan Kleiman
Shrubs and vines can sometimes be underappreciated, or worse, unknown. I will present a blog now and then on those species growing at Nachusa Grasslands. I am starting with five shrubs that we have good photos for, although we have identified at least 45 shrubs species and 20 vines (some woody and some herbaceous). By shrub I mean woody plants that attain less than 20 feet in height and often have multiple stems rising from the same roots. I will not include species that normally grow into trees, such as oaks (these and other trees can be shrub-like in form due to repeated fires causing them to re-sprout with multiple stems).
I seek to understand the shrub component of Nachusa more fully. I do think from my reading and observation that many of the shrubs were historically present in our area in thickets or along waterways, not as single bushes dotting the prairie. I think we should carefully plant the seeds of shrubs in appropriate places. Some bird species, such as Bell’s vireo, yellow-breasted chat, willow and alder flycatchers, cedar waxwing, common yellowthroat, and indigo bunting, as well as others, particularly need shrub habitat.
Shrubs are a major component of Nachusa’s grassland ecosystem in certain places. The Nature Conservancy calls our region the Prairie-Forest-Border Ecoregion. The State of Illinois calls our natural division the Rock River Hill Country-Oregon Section.
Writing in the Geological Survey of Illinois in 1873, James Shaw said of Lee County, “The north-western part of the county, where Rock river cuts across the corner, is rough, hilly, and in places picturesque, especially in the vicinity of that stream. The hills and ravines in this locality are partially covered with dense underbrush and scattering timber.”
In 1860 Dr. M. S. Bebb described the flora of Ogle County in a letter to a friend, which was also shared in a publication called Prairie Farmer. He says, “The rise at the border of the valley is usually covered with forest trees which have here found protection from the prairie fires, such as Quercus macrocarpa, Tilia Americana, &c with a variety of undershrubs and herbaceous plants, common everywhere in the woods of this latitude...” In the part about the groves he says, “Beneath we find an abundant growth of shrubs, principally Hazel (Corylus Americana) and Cornus paniculata*, the Hazel often extending out into the prairie for a mile or more, forming what is called a 'Hazel ruff'.”
Mary Sackett wrote in her journal in May of 1842, “Sometimes our road lay across the prairie, sometimes through the thickets where the crabapples, choke cherries, strawberries and other fruits were in bloom, making the air very fragrant.”
Some of our shrub species seem weedy and others difficult to grow, or even rare. This is likely due to the past disturbances such as plowing, over grazing, and over shading, or lack of disturbance by fire.
* Cornus paniculata is now Cornus racemosa, gray dogwood.
Ninebark Physocarpus opulifolius, Rose Family Rosaceae
This is a gorgeous, widespread native shrub. I just saw some on the Olympic Peninsula. Its genus name Physocarpus is Greek, meaning “fruit like a pair of bellows.” The species name opulifolius is Latin, meaning “splendid foliage” or having the leaves of Viburnum opulus (referring to a European plant, Guelder rose). Luckily this species is hard to misidentify here at Nachusa Grasslands.
Besides having good nectar for bees and butterflies, the large landing platform of the flower clusters is perfect for beetles, and the pollen is easily available to their chewing mouthparts.
The clustering fruits have unique bladder coverings, and in fall the fruit and leaves can often be quite colorful.
The common name of ninebark refers to the papery and shreddy bark of older branches. In open growing situations the shape of this shrub tends to rounded with weeping branches drooping to the ground. It is said it reaches a maximum height of ten feet, but I have not seen one taller than about seven feet here.
At Nachusa we have a few ninebark here and there, often mixed with other shrub thickets and fence lines with such species as American plum and dogwood. It is said that it prefers stream edges, gravel bars, moist thickets, but it is also found in dry areas here.
Many cultivars of this species have been developed by plant nurseries.
Prairie Willow Salix humilis, Willow Family (Salicaceae)
The genus Salix is Latin for willow, and humilis is also Latin, meaning low, humble, grounded, or from the humus (earth). I have not seen it taller than three feet here, and I can only think of five clumps outside of the one next to the Headquarters parking lot, so look out for this special bush, usually on dry remnant hills.
Deer and rabbits will browse the twigs and leaves. The catkins and nectar are very important to a great many insects in the spring.
Willow bark is the original aspirin, in use for at least 3500 years!
Common Elderberry Sambucus canadensis, Moschatel Family (Adoxacea, formerly in Caprifolicaeae)
Sambucus is Latin for elder-like, perhaps also derived from Greek sambuce, an ancient wind instrument, referring to the use of the stems to make whistles after removing the pith. Sometimes this shrub is called American elder. Elderwood in Europe was used to make a kind of harp called a sambuca. Canadensis refers to Canada, the country where this species finds its most northern distribution. This species extends all the way south to Bolivia.
Elderberry forms colonies by root suckers and is most often found on our fence lines. The bark of the stems has distinctive, raised dots (lenticels) and leaf scars with connecting lines between the opposite compound leaves (not to be confused with ash species, Fraxinus).
I have noticed that the cluster in my yard flowered most profusely the same year it had been burned, rather unlike many other shrubs we have, which can take several years post burn to flower. The flowers can be used to make a lemon-scented drink. But the berries are the best known part of the plant, used in wines, jams, jellies, and pie fillings.
The flowers attract a small variety of insects. Leaves and twigs are browsed by deer, and the fruit is eaten by all kinds of birds and other animals. Unripe fruit, leaves, and stems are toxic to humans. Cooking the ripe fruit destroys the alkaloids.
Smooth Sumac Rhus glabra, Cashew family (Anacardiaceae)
This family of plants produces urushiol, an irritant, and includes poison ivy, mango, and cashews. Smooth sumac does not seem to irritate. Rhus is the classic Latin name for this genus, while glabra is Latin for smooth. This is Nachusa Grasslands’ only extant Rhus, as far as I know. We have, however, planted fragrant sumac (Rhus aromatic) in some areas. Smooth sumac is claimed to be the only native shrub found in each of the lower 48 states.
Smooth sumac tends to grow in large clones that can sometimes shade out other species. Our fires often keep it shorter and sparse enough to allow prairie under the stems. In some places stewards have tried to reduce sumac stems through basal bark treatment.
Individual shrubs are either male or female. The flowers, pollinated primarily by bees, also attract a number of beetles and bugs. It seems that the leaf beetle, Blepharida rhois, is the only insect that can eat the leaves which contain strong tannins, phytols, and compounds related to gallic acids. The beetle larva puts its concentrated feces on its back to deter predators.
At Nachusa, smooth sumac is the last shrub to leaf out in the spring and one of the first to lose chlorophyll in the fall, usually turning a brilliant red. The bright red fruits have a lovely lemon taste and tartness. They can be eaten and used to make a refreshing drink, and in fact have been for thousands of years. Many animals eat the fruit as well, and various natural dyes have been made from all parts of the shrub for coloring cloth and plant fibers.
Wafer Ash or Common Hop Tree Ptelea trifoliate, Citrus family (Rutaceae)
Ptelea is Greek for elm, alluding to the winged fruits similar in appearance to elm seeds.
Trifoliate is Latin referring to the three leaflets of each leaf. It is neither an ash nor a hop, although the strong odor of the plant is similar to, but not as nice as, the beer-making hops. The fruits were tried as a hop substitute to no lasting effect. The pale greenish-white flowers attract bees in the spring. The wind-carried seeds turn brown in the fall and persist into winter. Each wafer actually has two seeds, unlike the wafers of elms.
This species, along with one other at Nachusa, prickly ash (wait for my next blog), are the only hosts on the preserve to the larva of the giant swallowtail butterfly, Papilio cresphontes.
This shrub is quite common here, tending towards weediness, in my opinion, as it pops up all over the prairie. It is usually no more than eight feet tall with multi-stems. I have occasionally seen them here or off site as tree size, six to eight inches in diameter and 20-30 feet tall. This is in situations without frequent fire.
Hyam, Roger and Richard Pankhurst. Plants and Their Names: A Concise Dictionary. New York: Oxford University Press Inc, 1995.
Kurz, Don. Shrubs and Woody Vines of Missouri. Jefferson City, MO: Conservation Commission of the State of Missouri, 1997.
Petrides, George A. A Field Guide to Trees and Shrubs. New York: Houghton Mifflin Company, 1986.
White, John. Rock River Area Assessment, Volume 2. Springfield, IL: State of Illinois, 1996.
Wilhelm, Gerould and Laura Rericha. Flora of the Chicago Region: A Floristic and Ecological Synthesis. Indianapolis: The Indiana Academy of Science, 2017.
If you would like to play a part in habitat restoration for native shrubs at Nachusa Grasslands, consider joining our Thursday or Saturday Workdays, or give a donation to the Friends of Nachusa Grasslands. Donations to Friends can be designated to support the ongoing stewardship at Nachusa.
I am a nature photographer, a freelance graphic designer, and steward at Nachusa's Thelma Carpenter Prairie. I have taken photos for Nachusa since 2012.
I have been a high school French teacher, registered piano technician, and librarian. In retirement I am a volunteer historian at Lee County Historical and Genealogical Society.