A Natural Calling

by | Oct 4, 2020 | Fauna, Landscapes, Native Plants

A black-capped vireo (Vireo atricapilla) in a cedar elm (Ulmus crassifolia) tree along the Mission Reach

A black-capped vireo (Vireo atricapilla) in a cedar elm (Ulmus crassifolia) tree along the Mission Reach. PHOTO Martin Reid

Lee Marlowe, the River Authority’s sustainable landscape ecologist who hired Reid for the job, says you know he’s seen something noteworthy if he lets out a swear word. And a black-capped vireo is indeed noteworthy: Striking and tiny with black heads and what look like white goggles,Vireo atricapilla is a threatened species, in large part due to habitat destruction. They require low, woody cover for nesting, much of which has been lost to development and grazing. Beneficial wildfires that keep shrubs growing close to the ground are also less common since human settlement (read more about the benefits of fire here), leaving fewer and fewer places for these birds to procreate.

But Reid has seen them and many other exciting species over the course of the three-year study, which took place from 2015 to 2018 (with ongoing incidental surveys into 2020). To be exact, the survey has documented nearly 65,000 birds actively using the area, with over 200 unique species in that number. He admits that, upon taking the job, he wasn’t really sure what to expect. But five years later, he is beyond satisfied: “I have been consistently surprised by diversity and number of birds. It’s better than I imagined.”

Birder Martin Reid in the restored native habitat along the San Antonio River, where he documented a black-capped vireo and many other bird species.

Birder Martin Reid in the restored native habitat along the San Antonio River, where he documented a black-capped vireo and many other bird species. PHOTO Lee Marlowe

Reid credits this biodiversity to the landscape’s “mosaic” style, which is what it sounds like: a variety of native habitat types contributing cover and forage for a mélange of wildlife, year-round. Along this stretch of river, that mosaic includes aquatic, scrub-shrub and prairie/savanna habitats, a combo that supports numerous resident and migrant birds, plus a few unexpected visitors, such as Audubon’s orioles (Icterus graduacauda), Couch’s kingbirds (Tyrannus couchii) and, of course, Reid’s swear-worthy vireo.

Plant selection is an important part of such a restoration, as it determines what will be fruiting and leafing at various times of year, not to mention providing nesting material and bank stabilization. Wildflower Center environmental designers were heavily involved in this part of the process, developing plant communities and seed mixes based on historical climax plant communities and reference visits; they also helped drive site design as part of a decade-long restoration done in collaboration with the River Authority, the U.S. Army Corps of Engineers, and Jacobs Engineering Group.

A painted bunting (Passerina ciris) rests in a huisache (Vachellia farnesiana) tree.

A painted bunting (Passerina ciris) rests in a huisache (Vachellia farnesiana) tree. PHOTO Martin Reid

To date, 317 native plant species have been documented along the restoration site, only 170 of which were deliberately planted (the rest are volunteers). Marlowe believes embracing those volunteers and working with nature, such as letting shoals stand where they didn’t pose flood risk and learning to love “weedy” plants such as black willows (Salix nigra) and hackberries (Celtis spp.), have been key to the project’s success.

According to Reid, you could find 20 bird species “in pretty much any urban habitat,” but they’re going to be birds that don’t need cover, such as blue jays and grackles. They’re seeing an additional 30 to 40 noteworthy bird species (after that baseline) along the Mission Reach restoration, compared to seven to 10 noteworthy species along unrestored parts of the river.

An interesting takeaway from their findings is support for a handful of oft-maligned native plants, such as giant ragweed (Ambrosia trifida), huisache (Vachellia farnesiana), retama (Parkinsonia aculeata), honey mesquite (Prosopis glandulosa), poverty weed (Baccharis neglecta), and the aforementioned hackberry and black willow. Marlowe enthusiastically touts these early colonizing species as “very important for birds and pollinators.”

Many birds, such as this house finch (Haemorhous mexicanus), are drawn to post-bloom common sunflowers (Helianthus annuus) for food.

Many birds, such as this house finch (Haemorhous mexicanus), are drawn to post-bloom common sunflowers (Helianthus annuus) for food. PHOTO Martin Reid

It’s hard to argue with photos from their survey depicting giant ragweed covered in seed-eating red-winged blackbirds (Agelaius phoeniceus) and denuded ragweed leaves teaming with bordered patch (Chlosyne lacini) caterpillars. Black willow branches are similarly covered in cedar waxings (Bombycilla cedrorum) and perched upon by belted kingfishers (Megaceryle alcyon), waiting and watching for a meal.

Giant ragweed provides low cover, while black willows make valuable waterside screens, says Reid. He calls the end result a “movement corridor” that contributes to the restoration’s holistic effect, with birds able to move safely from one type of habitat to another throughout the seasons — something he’s been lucky enough to watch firsthand for several years now.

When told he’s got a pretty enviable job, walking a beautifully restored riverscape, looking for and documenting birds, Reid replies with a laugh, “Somebody’s got to do it.” And it’s a good thing he is: Native plant enthusiasts believe in the habitat mantra “plant it and they will come,” but we’ll take all the proof we can get.