Investigating Chestnut-Bellied Scaled Quail Declines in South Texas
Request for Proposals November 2020
John McLaughlin, West Texas Quail Program Leader
Chestnut-bellied scaled quail (Callipepla squamata castanogastris) are one of two scaled quail sub-species in the state. Unlike the widespread Arizona scaled quail (C. s. pallida) commonly associated with open grasslands, chestnut-bellied scaled quail are restricted to the Tamaulipan Brushlands of South Texas and associated with denser, diverse thorn-scrub vegetation. The North American Breeding Bird Survey indicated an annual decline of 4.5% from 1965 to 2015, accelerating to 8.5% from 2000 to 2015. These data are supplemented by Texas Parks and Wildlife Department’s Annual Roadside Surveys, which show a decline from 6.29 birds/route (2000 to 2009) to 1.23 birds/route (2010 to 2019) over the last 20 years. Nowhere within the greater species geographic range have declines been more severe than South Texas.
Researchers hypothesize that landscape level changes in the quality, quantity and composition of habitat are the primary driver of population trends. In 2019, the Western Association of Fish and Wildlife Agencies’ Western Quail Working Group identified scaled quail declines as a major conservation issue for 2019 and beyond; TPWD currently lists scaled quail as a Species of Greatest Conservation Need. Research is needed to identify limiting factors and support ongoing conservation efforts.
Habitat loss and fragmentation represent the primary threats to quail populations in Texas. In particular, the conversion of native, undisturbed thorn-scrub vegetation in South Texas has disproportionately affected chestnut-bellied scaled quail. These birds require large, intact habitat tracts characterized by diverse shrub species, modest herbaceous cover and abundant bare ground. Reductions in habitat connectivity result in imperceptible habitat islands, within which demographic performance is reduced, environmental susceptibility is increased and local extirpation becomes likely. A complex matrix of agricultural production, emerging energy infrastructure and novel land-use changes (e.g., wildlife management) illustrate the scope of landscape changes and challenges.
Pursuing this research would directly address Goal #3 in the most recent Upland Gamebird Strategic Plan (2021) which states, “Promote upland game bird research and the restoration of native habitats for upland game birds using science-based management techniques.” Tying conservation objectives to changes in agriculture, energy development and land-use are all addressed as needs in subsequent sections of that plan. The loss of native, virgin brushlands and investigating chestnut-bellied scaled quail demographics are further listed as needs within the Tamaulipan Brushlands/South Texas Plains region. Understanding the complex dynamics of change in this region and their impact on scaled quail populations is a pressing need.
Research should focus on assessing habitat conditions where chestnut-bellied scaled quail populations are currently successful (i.e., stable populations) compared to where populations are currently declining (i.e., unstable populations). Research should simultaneously focus on habitat use by scaled quail and demographic differences between the two population types (stable vs. unstable) with emphasis on the role of brush. This work should be conducted within the boundaries of the South Texas Plains (Gould Ecoregion) and/or the Tamaulipan Brushlands (Bird Conservation Region). Research must be conducted at a minimum of 2 study sites per population type. In order to be considered for funding, proposals must address objectives 1 and 2 below. Objective 3 is optional.
- Assess and compare habitat conditions between stable and unstable populations types:
- Identify any differences in habitat characteristics between sites (e.g., cover, species richness, composition, structure, undisturbed versus disturbed brushland).
- Incorporate ancillary habitat metrics (e.g., habitat scale, interspersion, patch size and density, connectivity).
- Assess and compare population demographics/movement between stable and unstable populations types:
- Utilize radio telemetry and/or Global Positioning System (GPS) technology to assess reproductive effort and success, survival and other relevant demographics.
- Utilize radio telemetry and/or Global Positioning System (GPS) technology to assess quail movements and habitat use.
- Relate demographics and movement directly back to habitat conditions (e.g., optimal configuration, upper/lower limits).
- Provide best management practices (optional – examples of topics to be addressed)
- Role of brush management? Livestock grazing? Herbaceous cover management?
- Management recommendations? Combination of techniques?
Expected Management Implications
As a united front emerges between TPWD and our partners, both here in Texas and regionally, continued investments in scaled quail conservation are needed. The seriousness of the challenges faced by scaled quail and the need to understand how chestnut-bellied scaled quail interact with evolving habitat matrices in South Texas are of paramount interest. As TPWD expands cost-share programs with their partners in South Texas (e.g., South Texas Grassland Restoration Incentive Program – Rio Grande Valley Joint Venture; Farm Bill – State Acres for Wildlife Management) it is essential that these conservation activities are guided by the most relevant and up-to-date research in order to maximize the funding available for the benefit of chestnut-bellied scaled quail.
- Brennan, L.A., D.L. Williford, B.M. Ballard, W.P. Kuvlesky, E.D. Grahmann, and S.J. DeMaso. 2017. The upland and webless migratory game bird of Texas. Texas A&M University Press, College Station.
- Fulbright, T.E., K.W. Davies, and S.R. Archer. 2018. Wildlife responses to brush management: a contemporary evaluation. Rangeland Ecology and Management 71:35-44.
- Fulbright, T.E., H.N Kline, D.B. Wester, E.D. Grahmann, F. Hernández, L.A. Brennan, and M.W. Hehman. 2019. Non-native grasses reduce scaled quail habitat. Journal of Wildlife Management 83:1581-1591.
- Rho, P., X.B. Wu, F.E. Smeins, N.J. Silvy, and M.J. Peterson. 2015. Regional land cover patterns, changes and potential relationships with scaled quail (Callipepla squamata) abundance. Journal of Ecology and Environment 38:185-193.
- Wied, J.P., H.L. Perotto-Baldivieso, A.A.T. Conkey, L.A. Brennan, and J.M. Mata. 2020. Invasive grasses in South Texas rangelands: historical perspectives and future directions. Invasive Plant and Science Management in print.