Guide to Birds of the Field Research Park

Roel Loera


Welcome to the Field Research Park The Edwards Aquifer Authority (EAA) established the Field Research Park (FRP) in 2020 as a protected site for the long- term study of soil restoration and land management practices and processes designed to improve groundwater quality and quantity. The FRP is located over the sensitive Edwards Aquifer Recharge Zone in northeastern Bexar County and consists of approximately 151 acres within in the Cibolo Creek watershed. Habitats Are More Than Homes Urbanization has transformed millions of acres of woodland, brush, and grassland habitat into industrial, housing, and agricultural areas. Habitats are the physical settings of ecosystems that support communities of living organisms like plants and animals. The relationship between plants and animals is an important part of maintaining the balance of an ecosystem. In ecosystems around the world, reliable sources of food and water and availability of habitat are key to the continued survival of living organisms, including humans. Birds act as important indicators of ecosystem health and perform essential functions such as pollination of flowering plants and pest control. At the FRP, a variety of habitats support a diverse and seasonally changing bird population. Many of these birds use several habitats, nesting in one and foraging in others. Food for Many Tastes The FRP is home to a diverse array of plant life that provides berries, insects, nectar, nuts, and seeds for hungry birds. Trees like Ashe Juniper, Buckeye, Cedar Elm, Hackberry, Mulberry, Live Oak, Texas Persimmon, and Walnut offer rich stores of energy in their berries and nuts. Wildflowers like Black-eyed Susan, Honeysuckle, and Sunflower provide nectar and seeds. Native grasses like Gramma grass, Indiangrass, and Texas Cupgrass are important seed sources. Painted Buntings, like those pictured on the cover, thrive on seeds available throughout their nesting season. Texas Cupgrass, like many native grasses, blooms and produces seeds from May through October. In addition to providing nectar and seeds, some wildflowers like Mallow and Sida host butterfly larvae, which become food for insect-eating birds like wrens. Similarly, trees such as Pecan, Hackberry, and Cedar Elm provide food, shelter, and act as hosts to insect larvae. Pecan trees bloom and attract insects in the spring. In the fall,



their abundant nuts provide much needed nutrition for many animals, including birds. Hackberry trees produce sweet fruits that persist into the fall and attract insects throughout the year. Cedar Elm trees uniquely bloom in the fall, attracting insects for resident birds and birds migrating to their wintering grounds in

Mexico, Central America, and South America. Keeping Track of Our Avian Community

The relationship between plants and animals plays an important role in maintaining the balance of an ecosystem. Trees, wildflowers, and grasses provide food and shelter to animals. Animals, like birds, provide pollination, pest control, and seed dispersal to plants. This relationship is supported by the building blocks of a balanced ecosystem: healthy soils, clean water, and sufficient water availability. Land management practices can be used to improve the building blocks of an ecosystem, its health, and ultimately the diversity of life that it can support. By monitoring bird life at the FRP, we gather information about the health of the FRP ecosystem and the impact of land management practices.

Food sources for birds at the FRP, clockwise from upper left: insects, Cedar Sage ( Salvia roemeriana) , EAA staff planting demonstration garden, Germander ( Teucrium canadense ), demonstration garden view, Purple Threeawn ( Aristida purpurea ).



Habitats of the FRP TheFRPencompasses threedistinct habitats, eachcharacterized by a particular combination of topography, soil, and plant life. Each of the habitats supports a diverse array of bird species in a range of activities, including foraging and nesting. The distribution of these habitats at the FRP is shown overleaf in the Field Research Park Bird Habitat Map on pages 6-7. Cibolo Creek, its tributary, and the surrounding trees constitute riparian areas at the FRP. Grassy meadows are scattered throughout Ashe juniper-oak woodlands, which dominate hilltops and sloped areas. Within these habitats, natural variation in topography, soil, and plant life creates numerous microenvironments. Illustrated below are some of these microenvironments that have been observed at the FRP.

Riparian Areas

Waterways Areas adjacent to creeks and rivers are critical for many birds. They provide nesting, food, and shelter for not only local birds but also migratory birds in need of rest stops. For migrating wading birds and shorebirds, the small aquatic organisms found here are an essential food source. Bottom Woodlands The rich, moist soils of bottom woodlands support a diverse array of plant species. Most woodland birds use this habitat in several ways, foraging for insects, berries, and seeds and nesting. Even Red- shouldered Hawks can be found here, hunting for small animals.



Open Meadows

Many bird species forage in openmeadows for abundant seeds and fruits produced by a variety of wildflowers and grasses. The plants also host numerous insects, which attract insectivorous birds. Predatory birds hunt in these areas for smaller birds and rodents.

Woodland Areas

Dense Woodlands Thick stands of Ashe Juniper and oak trees provide cover for many bird species. This habitat is preferred by many nesting birds. Insect-eating and predatory birds also seek out insects and small mammals readily found in these areas. Open Woodlands Interspersed trees and grassy areas supply food, shelter, and nesting in the form of grubs and insects, canopy cover, and tree cavities. Woodpeckers are particularly attracted to this habitat. Hummingbirds collect nesting material from tree-hosted lichens and mosses. Hilltop and Sloped Woodlands These upland and sloped areas host a mix of Ashe Juniper and oak trees that is preferred by Golden-Cheeked Warblers for nesting. Many birds use this setting in conjunction with other habitats on a daily basis.




Field Research Park (FRP)

Morgan’s Wonderland Camp


Education Outreach Center (2021)

Rendering of Education Outreach Center, scheduled to open in 2021 at Morgan’s Wonderland Camp.

This map was created for demonstrative use by the EAA and not intended Western Slopes - visible from the main gate and adjacent to Morgan’s Wonderland Camp and the Education Outreach Center, the western portion of the FRP is dominated by juniper- covered slopes and small gullies. Awater well located in this area is the focus of ongoing EAA groundwater research at the FRP.




View of FRP Headquarters overlooking Cibolo Creek.


FRP Headquarters

FRP Headquarters and Cibolo Creek - accessible via gravel road from the main gate, the eastern tract of the FRP encompasses a range of habitats, from creekbeds to dry juniper hilltops. The gravel road leads to the FRP Headquarters and demonstration garden, located on the bank of Cibolo Creek. for other purposes. This map is to be used as an informational tool only.



Birds at the FRP During the spring of 2020, EAA staff identified 59 bird species, including the endangered Golden-cheeked Warbler! This

warbler is migratory, spending its winters in Mexico and Central America. During the spring, it flies north to breed exclusively in the Texas Hill Country. The Golden-cheeked Warbler prefers woodlands with mature Ashe Junipers in steep-sided canyons or slopes. Mature, or old-growth, juniper trees are essential for

Male Golden-cheeked Warbler foraging at the FRP, spring 2020.

the warbler’s survival—its nests are constructed from strips of juniper bark readily removed from the shaggy trunks of mature trees. The primary threat to the Golden-cheeked Warbler is loss of habitat and the fragmentation of remaining habitat. This includes the loss of nesting habitat in Texas and the loss of wintering habitat in Mexico and Central America. A sighting of this special bird at the FRP indicates the presence of vital habitat. Bird species at the FRP vary throughout the year as a result of migration. Many birds fly hundreds to thousands of miles every spring and fall. Some winter in Mexico, Central America, and South America, making the long flight back to North America for the breeding season. The paths of these migration flights North American Migratory Bird Flyways

Central Flyway

Pacific Flyway

Atlantic Flyway

Mississippi Flyway

Figure 1: Extent of the four main North American flyways. Map credit United States Fish and Wildlife Service.



are grouped into four flyways: the Pacific, Central, Mississippi, and Atlantic flyways (Figure 1). Nearly 400 species of birds use the Central Flyway. Texas offers these migrating birds at least 23 natural sanctuaries, where birds rest and feed during their journey. It is important to note that unusual atmospheric conditions, including cold fronts, disturbances in the Gulf of Mexico, and high winds, can affect the flight path of birds and funnel birds from all flyways into the Central Flyway. During these events, a higher than usual diversity of migrating birds can be observed in Texas. For seasonal and resident birds alike, the availability of food, water, and shelter is essential to their survival. Migratory birds rely on the presence of healthy habitat throughout their flyway to recover from their strenuous and exhausting journeys, while year-round birds depend on healthy local habitat for their entire life cycles. The essential role of carefully managed ecosystems, like that of the FRP, is to provide plentiful food, water, and shelter for all birds. In Your Backyard You don’t have to be an experienced birdwatcher or need expensive equipment to enjoy and support bird life. The easiest way to start is by observing birds in their natural setting, whether that is a backyard, neighborhood park, or wildlife preserve. By becoming familiar with different species and their needs, you can identify what resources they may lack. During hot summers and winter freezes, supplemental food and water can help nourish stressed birds. Year-round residents and seasonal species benefit from these supplements, especially migratory birds that need to replenish their energy during their long journeys. By incorporating native wildflowers and grasses into landscapes, homeowners can turn their backyards into habitats rich in food and shelter. Landowners can consult their local conservation agency about a wildlife or land management plan. Local chapters of organizations like the Audubon Society engage in community projects to support bird life. With so many opportunities to choose from, all you need to do is get involved!



Gallery of FRP Birds On the following pages is a selection of birds observed and photographed at the FRP in the spring of 2020. Larger birds at the FRP include the vocal Mockingbird and reclusive Yellow- billed Cuckoo reside in the tree canopy. Scavengers and predators like Black Vultures and Red-tailed Hawks can often be seen soaring overhead on thermal currents, while Red- Shouldered Hawks patiently perch high in oak trees. In the understory, a myriad assortment of warblers can be observed gleaning insects from leaves and tree bark. Larger songbirds like the buntings, Cardinal, and Tanager often perch higher in the tree canopy before descending to forage for seeds and insects. Small active birds can be seen scampering over rocks in search of insects or hovering above wildflowers.

Larger Non-Predatory Birds

Northern Mockingbird Mimics up to 200 bird calls and man-made sounds Often sings at night Designated as the State Bird of Texas in 1927 Yellow-billed Cuckoo Diet in spring and summer consists mostly of caterpillars Generally shy, hiding in tree canopy Winters in South America, population declining due to habitat loss



Predatory & Scavenging Birds

Black Vulture Bare head and neck evolved for sticking their heads inside carrion to eat Will regurgitate food in self-defense Light grey outer edge of wing visible when soaring overhead Red-tailed Hawk Most common and widespread hawk in North America Plumage varies between regions and subspecies Generally identified by reddish tail Red-shouldered Hawk Very vocal forest hawk Often flies with several wingbeats followed by gliding Reddish shoulders and barring on chest Loggerhead Shrike Predatory songbird nicknamed the “Butcher Bird” Impales variety of insects and small animals on thorns or fence barbs Frequently perches high in the open to watch for potential prey



Colorful Larger Songbirds

Indigo Bunting Forages mostly on ground for insects, seeds, and berries Male breeding plumage pictured; grey- brown in winter Winters from south Florida to the Bahamas, central Mexico, and Panama Painted Bunting Male is one of North America’s most colorful birds; female is olive green Diet consists mostly of seeds Winters in Mexico to South America

Northern Cardinal Diet includes seeds, fruits, and insects Often observed in pairs Male is brilliant red, female is light brown with same orange-red bill as male

Summer Tanager Frequently raids beehives and paper wasp nests for larvae Male is brilliant red; female is olive yellow Winters in Mexico to South America




American Redstart Very active, flashing tail and wings while foraging Diet consists mostly of insects Winters in Mexico, Central and South America Black and White Warbler Creeps along tree limbs to forage for insects Male and female plumage similar Winters in Mexico to South America

Black-throated Green Warbler Like Golden-cheeked Warbler, but with olive back and yellow underside Actively forages for insects in undergrowth Winters in Mexico to South America

Common Yellowthroat One of most abundant warblers Actively forages in undergrowth for insects and spiders Winters in Bahamas, West Indies, and south to Panama



Warblers continued

Golden-cheeked Warbler Endangered species that nests only in Texas Prefers woodlands with mature Ashe Juniper trees Winters in Mexico, Honduras, Nicaragua, and Guatemala Magnolia Warbler Distinctive bright yellow underside Forages for insects and berries, often with fanned tail Winters in Mexico to South America

Nashville Warbler Eats exclusively insects Distinctive white eye-ring and yellow throat Winters south to El Salvador and Honduras

Yellow-breasted Chat (warbler) Largest of the North American warblers Tail is distinctively long for a warbler Winters south to Panama, nesting in North America



Other Small Active Birds

Carolina Chickadee Small, active woodland bird Familiar chickadee-dee-dee call Defends nest with snake-like hiss and wing slaps

Ruby-throated Hummingbird Diet consists of insects, nectar, and sap Known to migrate across the Gulf of Mexico Winters in Mexico to Costa Rica

Lark Sparrow Size is unusually large for a sparrow Strongly patterned head and distinctive black chest spot Searches for insects and seeds on ground

Canyon Wren Resides in rocky canyons and outcrops Reuses nest for multiple years Actively forages in rock crevices, seeking insects and spiders



Birds Recorded at the FRP A complete listing of all bird species observed at the FRP is provided below. These sightings are current as of July 2020. Species are organized alphabetically by type. For example, the Golden-Cheeked Warbler is found near the end of the list, with other warblers. Species that visit the FRP during their spring and fall migrations, as well as those observed outside their usual range, are indicated as migratory. Birds that spend all four seasons in south central Texas are indicated as resident.

Common Name

Scientific Name



Passerina cyanea

✓ ✓

Indigo Bunting Painted Bunting Northern Cardinal Carolina Chickadee

Passerina ciris

Cardinalis cardinalis Poecile carolinensis

✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓

Molothrus ater

Brown-headed Cowbird Yellow-billed Cuckoo Common Ground Dove

Coccyzus americanus Columbina passerina

Columbina inca Zenaida macroura Zenaida asiatica

Inca Dove

Mourning Dove

White-winged Dove

Haemorhous mexicanus Myiarchus cinerascens

House Finch

Ash-throated Flycatcher Scissor-tailed Flycatcher Blue-gray Gnatcatcher

✓ ✓

Tyrannus forficatus Polioptila caerulea

✓ ✓

Spinus psaltria

Lesser Goldfinch Blue Grosbeak

Passerina caerulea

Buteo lineatus

Red-shouldered Hawk

✓ ✓

Buteo jamaicensis Archilochus alexandri Archilochus colubris Cyanocitta cristata Tyrannus verticalis Regulus calendula Mimus polyglottos Chordeiles acutipennis

Red-tailed Hawk

Black-chinned Hummingbird Ruby-throated Hummgbird

✓ ✓

Blue Jay

Western Kingbird

✓ ✓

Ruby-crowned Kinglet Northern Mockingbird

Lesser Nighthawk



Common Name

Scientific Name



Icterus bullockii Sayornis phoebe Setophaga ruticilla Lanius ludovicianus

Bullock’s Oriole Eastern Phoebe American Redstart Loggerhead Shrike European Starling Barn Swallow Cliff Swallow Chimney Swift Summer Tanager Lark Sparrow

✓ ✓ ✓

Chondestes grammacus

Sturnus vulgaris Hirundo rustica

✓ ✓ ✓ ✓

Petrochelidon pyrrhonota

Chaetura pelagica

Piranga rubra

Baeolophus atricristatus Toxostoma longirostre Vireo philadelphicus

Black-crested Titmouse Long-billed Thrasher

✓ ✓

Philadelphia Vireo White-eyed Vireo

Vireo griseus

✓ ✓ ✓

Coragyps atratus Cathartes aura

Black Vulture Turkey Vulture

Mniotilta varia

Black-and-White Warbler Black-throated Green Warbler

✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓

Setophaga virens Setophaga fusca Geothlypis trichas

Blackburnian Warbler

Common Yellowthroat (warbler)

Setophaga chrysoparia Setophaga magnolia Geothlypis philadelphia Leiothlypis ruficapilla Leiothlypis peregrina Cardellina pusilla Setophaga petechia

Golden-cheeked Warbler

Magnolia Warbler Mourning Warbler Nashville Warbler Tennessee Warbler Wilson’s Warbler

Yellow Warbler

Icteria virens

Yellow-breasted Chat (warbler)

Dryobates pubescens Melanerpes aurifrons

Downy Woodpecker

✓ ✓ ✓ ✓ ✓ ✓

Golden-fronted Woodpecker Ladder-backed Woodpecker

Picoides scalaris

Thryomanes bewickii Catherpes mexicanus Thryothorus ludovicianus

Bewick’s Wren Canyon Wren Carolina Wren



Digital Resources Cornell Lab of Ornithology Audubon Society Lady Bird Johnson Wildflower Center Texas Parks and Wildlife Department

Local Resources Balcones Canyonlands National Wildlife Refuge Bexar Audubon Society Government Canyon State Natural Area Mitchell Lake Audubon Center Edwards Aquifer Authority & the Edwards Aquifer Conservancy The Edwards Aquifer Authority (EAA) manages, enhances and protects the Edwards Aquifer – the primary source of water for personal, agricultural, municipal, and industrial uses for more than 2 million people in South Central Texas. The EAA’s jurisdiction covers 8,000 square miles and ranges from Uvalde to Hays Counties, and parts in-between. It is governed by a 17-member board of directors representing the interests of constituents from across the Edwards Aquifer region. The Edwards Aquifer Conservancy (EAC) is a 501(c)3 nonprofit organization established for the benefit of the EAA. Funds raised by the EAC enhance the resources available for programs and initiatives, such as public education and information outreach, the pursuit of critical scientific field research, ongoing conservation efforts, and hazardous materials training in the Edwards Aquifer region, to name a few. The EAC’s current major efforts include the construction and operation of its Education Outreach Center, located on the Morgan’s Wonderland Camp, and expected to be opened to the public in 2021.



Author Roel Loera, Aquifer Protection Coordinator Mr. Loera was hired by the EAA in December 2005 and has been a member of the Aquifer Protection team since January 2019, where he leads the coordination, monitoring, and reporting for the Edwards Aquifer Protection Program conservation easements. He holds a B.S. in Range and Wildlife Management from Texas A&M University-Kingsville. Prior to joining the EAA, Roel guided birding trips in South Texas and worked as a keeper in the San Antonio Zoo’s avian department. Design & Editing

Jesse Chadwick, Hydrologic Coordinator Ms. Chadwick analyzes groundwater and geologic data for the EAA’s Aquifer Science program. She earned an M.S. in Earth Sciences from Montana State University and a B.A. in Geology from Princeton University. Direction Thomas Marsalia, Aquifer Protection Supervisor Mr. Marsalia oversees the monitoring of conservation easement properties in the Edwards Aquifer Protection Program. He earned a B.S. in Environmental Management from University of Houston-Clear Lake. GIS and Mapping Taylor Bruecher, Hydrologic Coordinator Ms. Bruecher performs GIS-based geospatial analysis for the EAA’s Aquifer Science program. She received a B.S. in Geography from Texas State University and is pursuing an M.S. in Geology from Sul Ross State University. Photography JesseChadwick Food Sources at the FRP (p. 3), Lark Sparrow (p. 15). Roel Loera Painted Buntings (cover), Waterways (p. 4), Bottom Woodlands (p. 4), Hilltop (p. 5), Golden-Cheeked Warbler (p. 8), Mockingbird (p. 10), Yellow-billed Cuckoo (p. 10), Vulture (p. 11), Red- tailed Hawk (p. 11), Red-shouldered Hawk (p. 11), Shrike (p. 11), Painted Bunting (p. 12), Cardinal (p. 12), Summer Tanager (p. 12), Black and White Warbler (p. 13), Golden-cheeked Warbler (p. 14), Ruby-throated Hummingbird (p. 15), Canyon Wren (p. 15). Becky Marsalia Indigo Bunting (p. 12), Redstart (p. 13), Black-Throated Green Warbler (p. 13), Yellowthroat (p. 13), Magnolia Warbler (p. 14), Nashville Warbler (p. 14), Yellow-Breasted Chat (p. 14), Chickadee (p. 15). ThomasMarsalia Open Meadows (p. 5), Dense Woodlands (p. 5).



Rendering of the EAA’s planned Field Research Observatory. This observatory would be located at the FRP and would implement a thorough science-based initiative to collect groundwater levels, water quality data, soil sampling and mapping of karst features like springs or seeps in the area. The principal purpose of the EAA Field Research Observatory is to develop, research, and implement practices that lead to enhanced water quality and quantity for the region.

900 E. Q uincy S treet S an A ntonio , T exas (210) 222-2204

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