The Wrens of Bexar County
by Bob Doe
Originally published in Volume 47, Number 2 (February 2001)
Let me start this article off with a simple challenge: How many species of wren can you find in Bexar County on a single day?
Nine wren species have been reported in the county. Of these, Carolina Wren, Bewick's Wren, and House Wren are widespread. Carolina and Bewick's Wrens are both abundant permanent residents, and House Wren is an abundant winter resident. Although there is much overlap in distribution, Carolina Wren tends to prefer the damp conditions of the riparian zones along stream courses, and Bewick's Wrens are more typical of the drier uplands. House Wrens occur in both the riparian zones and uplands, but seem to prefer areas with downed branches and trees, such as brush piles. A trip to McAllister Park should yield all three.
Three other wren species (Canyon, Winter, and Marsh) are also fairly easily found in Bexar County during the winter months. Canyon Wren is a locally common permanent resident along rocky cliffs and canyons in northern Bexar County. Unfortunately, the best habitat is not currently accessible to birders. Government Canyon State Natural Area contains several breeding pairs. I have also found Canyon Wren at various locations along Leon Creek, Helotes Creek, Scenic Loop Drive in Grey Forest, Babcock Road north of Loop 1604 and at other locations. Canyon Wrens can sometimes be heard, and occasionally seen, at the quarry adjacent to Eisenhower Park, and probably at other quarries.
Winter Wren (illustrated at right) is an uncommon to common winter resident, but is restricted to riparian areas containing lots of downed wood. This species is not as vocal as some of the other wrens, and can be easily overlooked as it creeps under and around log jams and other flotsam, tree roots, and vines. Look for this bird along the Medina River, San Antonio River (Avenue A), Olmos Basin, Hidden Valley, Medio Creek, Leon Creek, Salado Creek (Ft. Sam Houston), and the riparian areas around Calaveras Lake. My experience along the Medina River suggests that there is a Winter Wren approximately every 200 yards along the river.
Marsh Wren is a locally common winter resident wherever there are Cattails or patches of Bulrushes. It is easily found (virtually 100 percent certain) at Calaveras Lake and Lake Braunig, although actually SEEING one is less certain. It is also occasionally found in wet brushy vegetation such as surrounding the ponds at Mitchell Lake (Basins 2 and 3, particularly), as well as roadside drainage ditches, stock pond outflows, etc.
Cactus Wren, although listed as "Common" in the checklist, has actually been a difficult bird for me to find in Bexar County. Although I have found it in many places, I know of only one place in the county that it is reliable (a certain hillside on Medina Base). Previously reliable sites (Government Canyon, UTSA campus) are much less reliable now. There are undoubtedly sites waiting to be discovered in southern Bexar County where this species occurs regularly.
Sedge Wren is rarely reported in Bexar County, most probably due to birder distribution and habitat accessibility rather than actual bird prevalence. The species prefers damp, grassy and weedy fields, but will occur along wet, weedy edges to lakes and ponds. Sedge Wren is fairly common along the Texas Coast, and should be looked for in the agricultural areas of eastern Bexar County, particularly fields and roadsides depressions that occasionally retain water.
Rock Wren is the least frequently reported wren in Bexar County, although again I believe the reported frequency reflects birder distribution rather than bird distribution. I have never seen Rock Wren in Bexar County, although I have seen it several times in Medina County. Rock Wrens occupy rocky cliffs, hillsides, and talus slopes, although they can also be found in other places with hard substrates (old cars in junk yards, old mining equipment, etc.). As opposed to Canyon Wrens, which prefer the moist, shady bottoms of canyons, Rock Wrens want their rocks exposed to the sun. Although you won't find these wrens often in Bexar County, some likely places to look would be road cuts (US 281, Loop 1604, SH 16), concrete rubble, old quarries, and the rocky faces of dams (Calaveras Lake, Braunig Lake and the flood control dams in northern Bexar County).
So, how many wren species can you find in Bexar County in one day?
Winter Wren, illustration by Arthur Singer, from Birds of the World (NY: Golden Press, 1961)
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