EN
Golden-cheeked Warbler Setophaga chrysoparia



Justification

Justification of Red List category
This migratory species is experiencing significant declines in its habitat in both its breeding and non-breeding range, and rapid population declines are being witnessed in response. Therefore, the species is precautionarily listed as Endangered.

Population justification
There is currently only one range-wide estimate of abundance for the species (Mathewson et al. 2012). Mathewson et al. (2012) conducted point count surveys in a subset of randomly selected habitat patches (301 patches total) across the breeding range in 2008–2009 and found density was most related to the predicted patch-specific occupancy probability based on the work of Collier et al. (2012). They estimated range-wide abundance for male birds to be ca. 262,013 (95% CI: 223,131 – 302,620). Using the density estimates of Mathewson et al. (2012), Hatfield et al. (2012) estimated there were ca, 11,600 – 18,300 male birds on conservation, recreation, and Department of Defense lands. Although other density estimates have been calculated for the species (i.e. Peak 2011, USFWS 2014, O’Donnell et al. 2015, Reidy et al. 2015, amongst others), these estimates are based on individual parcels of land and ignore the spatial variability in densities across the breeding range. Regardless, based on the estimates of Peak and Thompson (2013), Sesnie et al. (2016), Reidy et al. (submitted per Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018) and Groce et al. (2010), the Alliance for Conservation of Pine-Oak Forests in Mesoamerica estimate that the number of territorial males found on publicly-owned land could be 9,687. The majority of its breeding range is on privately-owned land though, so the overall population size is likely to decline as habitat is lost.

Trend justification
Nesting habitats are being cleared in the breeding grounds for land development, ranching and agriculture; and habitats are being lost in the wintering grounds primarily owing to deforestation for livestock grazing, fuel wood collection, forest fires and beetle infestation. The rate of range-wide breeding habitat loss has been estimated at 29% between 1999-2001 and 2010-11 (Duarte et al. 2013), and based on only a portion of the breeding range, habitat loss has been estimated at 33% between 2004-05 and 2016 (Heger and Hayes in prep.). Rapid declines are therefore expected in response to such habitat loss and population declines of >50% have occurred on some of the monitored plots in Balcones Canyonlands Preserve, despite there being no change in the habitat there (Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018). Contrastingly however, Duarte et al. (2016b) showed that overall abundance in the same plots increased from 1998-2012 due to substantial immigration into each plot year on year; Fort Hood military base also found an increasing trend within their survey plots (Duarte et al. 2014). Such changes likely reflect the immigration of birds into these areas from areas outside of managed lands where habitat is being rapidly lost (A. Duarte in litt. 2020). Monitoring data from the non-breeding range has however, exhibited an extremely rapid reduction of 50% over the past 4 years (2014-18) (Alliance for Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018). Therefore, the overall rate of decline is precautionarily assessed as falling in the range 50-79% over ten years, despite immigration into some assessed plots. High rates of population decline are modelled to continue into the future with population viability analyses suggesting an extinction risk of 51% over a 50 year period when assuming dispersal rates are low (Duarte et al. 2016a) and 19% over a 20 year period (Reidy et al. submitted per Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018). Notably, Duarte et al. (2016a) found that the extinction risk was highly sensitive to the assumed dispersal rates (a parameter that has yet to be estimated for the species) and annual survival probabilities (a parameter that has only been estimated at two locations across the breeding range [Duarte et al. 2014 and Reidy et al. 2018]) and the risk of quasi-extinction approached 0 when assuming dispersal was higher (A. Duarte in litt. 2020). Furthermore, these risks could be even greater since certain other factors such as catastrophic events, and any potential habitat changes within preserves, were not taken into account (Alliance for Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018).

Distribution and population

Setophaga chrysoparia is a neotropical migrant with a restricted breeding range in mature Ashe juniper (Juniperus ashei)-mixed oak (Quercus spp.) woodlands of the Edwards Plateau, Lampasas Cut Plain and Central Mineral Region, Texas, USA (Ladd and Gass 1999). A vast range of studies have attempted to estimate the amount of available habitat there is for the species (per Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018; Pulich 1976; Wahl et al. 1990; DeBoer and Diamond 2006; SWCA 2007; Diamond 2007; Loomis Austin 2008; Morrison et al. 2010; Collier et al. 2010, 2012; Hatfield et al. 2012; Matthewson et al. 2012; Duarte et al. 2013, 2016a; Diamond et al. 2016; Heger and Hayes in prep.). Collier et al. (2012) and Duarte et al. (2013) estimated potential range-wide breeding habitat to be 16,787 km2 and 15,783 km2, respectively. Notably, Collier et al. 2012 used repeated detection/non-detection surveys and spatial occupancy models to account for imperfect detection when estimating patch-specific occupancy probabilities. They estimated that 6,299 km2 of their delineated potential breeding habitat had an occupancy probability of >0.9 and 11,243 km2 of their delineated potential breeding habitat had an occupancy probability of >0.5. Recently, Heger and Hayes (in prep.) estimated that in 2016, there was c.4,560 km2 available breeding habitat however, this is likely to be an overestimate and the Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. (2018) have estimated the Area of Occupancy during the breeding season to be 1,768 km2.

It winters mainly in the mountainous Pine-Oak ecoregion of Central America, from southern Mexico (Chiapas), Guatemala, El Salvador, Nicaragua, and Honduras, where it is uncommon to fairly common (Ladd and Gass 1999, Rappole et al. 2000, Jones and Komar 2007, King et al. 2008). There are recent reports/records from Costa Rica (Garigues 2002) and Panama (Jones and Komar 2006). There is no consensus on the extent of suitable habitat within the species's wintering range, and its ecological integrity has not been established as to assess the conditions required to maintain optimal wintering populations (Alliance for the Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018).

Ecology

The species breeds in juniper-oak woodlands, where it depends on Ashe Juniper Juniperus ashei bark for nesting material (Lockwood 1996), and individuals are highly philopatric, returning to the same site each year (Ladd and Gass 1999); the species has been shown to exhibit strong conspecific attraction when selecting areas to establish breeding territories (Farrell et al. 2012). The species does not saturate all available habitat though (it may require patches of >15 ha in rural areas and >26 ha in urban areas [Robinson et al. 2018, Reidy et al. submitted per Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018]), and density increases with greater canopy cover and height, and increased cover of mixed juniper-oak (USFWS 1992; Peak and Thompson 2013; Reidy et al. 2016, 2017). Nest building begins in early to mid-March, and eggs may be laid until mid-May (Ladd and Gass 1999, J. Reidy in litt. 2012, J. Scalise in litt. 2018). Although productivity appears to be higher in Texas Red Oak (Quercus buckleyi) habitat compared to Post Oak (Q. stellata) (Marshall et al. 2013), Campomizzi et al. (2012) found that the relationship between reproductive success and habitat conditions varies across the breeding range.

In winter, it occurs predominantly in pine-oak forested habitats in mixed-species flocks, foraging at sites with a high density of "encino" oaks (in comparison to pines and other oak species) at 1,100-3,000 m (Vidal et al. 1994, Thompson 1995, Ladd and Gass 1999, Rappole et al. 1999, 2000, King et al. 2008, 2012) and oaks appear to be essential in the wintering habitat (Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018). It was thought to have a wider winter habitat tolerance (and may be tolerant of moderate levels of logging and grazing [Rappole et al. 1999]), but this requires substantiation (J. Sterling in litt. 1999).

Threats

Breeding habitat is subject to clearing for land development and agriculture (Ladd and Gass 1999), leading to increased habitat fragmentation, which can impair gene flow (Lindsay et al. 2006, 2008; Athrey et al. 2011), and increase nest predation and brood parasitism (Pulich 1976, Peak 2007, Reidy et al. 2009b, Sperry et al. 2009); thus reducing productivity (Peak and Thompson 2014). Long-term changes in this species's habitat have been documented (Heger 2012, Heger and Hayes in prep.), such that (based on only a portion of the range) potentially 23% of suitable breeding habitat was lost between 1993-94 and 2004-05 and 33% lost from 2004-05 to 2016. Duarte et al. (2013) additionally found a 29% reduction in total breeding habitat between 1999-2001 and 2010-11. Moreover, both Duarte et al. (2016a) and Diamond et al. (2016) found that lost habitat was unlikely to regenerate after a habitat patch was cleared. The 2011 drought and 2015 floods have potentially had an additional impact on habitat loss (Heger and Hayes in prep., Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018), though these will have been incorporated as part of the Heger and Hayes (in prep) analyses. The 2011 drought also reinforced efforts to try to eradicate Ashe junipers (Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018). Importantly, habitat loss and fragmentation can lead to reduced connectivity across habitat patches and connectivity has been found to be essential to maintain species viability at both the local (Duarte et al. 2016b) and range-wide scale (Duarte et al. 2016a).

The decline may also be being driven by forest fires, logging and firewood-extraction, and agricultural conversion for cattle reducing pine-oak habitats in its wintering range (Ladd and Gass 1999, Rappole et al. 2003a, J. Lyons in litt. 1999, Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018). Millions of hectares of forest burned between 1998 and 2016, which is equivalent to 33% of total area of the ecoregion (Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018). It is thought that suitable wintering habitat may be considerably more limited than that available in the breeding range with wintering habitat able to support just 15% of the population that could be supported by breeding habitat (Rappole et al. 2003b). Forest loss throughout this species's entire range is currently estimated at ~3.6% across a ten year period (Tracewski et al. 2016). An infestation of Southern Pine Beetle (Dendroctonus frontalis) since 2015, particularly in Honduras, has had a significant impact on forests in the wintering range, increasing the risk of catastrophic fires (Alliance for the Conservation of Mesoamerican Pine-oak Forests in litt. 2018).

A range of other factors could also have an influence on the species and its habitat. Predation of incubating females by rat snakes (Elaphe spp.) (and potentially other nest predators [C. Harper in litt. 2016]) appears to be an important contributor to adult mortality, accounting for perhaps 15% of breeding female deaths (Reidy et al. 2009a). White-tailed Deer (Odocoileus virginianus), invasive Wild Boar (Sus scrofa), invasive plants and oak wilt fungus (Ceratocystis fagacearum) and increasing wildfire risk may all impact the habitat (Russell and Fowler 1999, Juzwik et al. 2008, USFWS 2014), while Tawny Crazy Ant (Nylanderia fulva) is expanding its range into central Texas, so could be a potential threat (LeBrun et al. 2013, Kumar et al. 2015). Adult mortality from vehicle and window strikes has also been reported (Reidy et al. 2018). Increasing anthropogenic noise, particularly via road construction, has also been considered as a threat however, recent studies have not evidenced any effect from such changes on the species (Lackey et al. 2011; Long et al. 2016, 2017). Climate change is also thought to have significant impacts on the species, as its Ashe juniper dominated woodlands are likely to be unable to shift with shifting climate in the breeding range (EPA 2009), and some tree species in the non-breeding range may contract their range by 50% by 2050 (Goméz-Mendoza and Arriaga 2007). A petition in the state of Texas is also currently attempting to have the species's Endangered species status removed, significantly threatening the habitat in which it resides (USFWS 2016, Doyle 2020).

Conservation actions

Conservation Actions Underway
Within the breeding range, federal lands that provide long-term protection include Department of Defense lands (U.S. Army Fort Hood, U.S. Air Force Joint Base San Antonio-Camp Bullis, and U.S. Army Corps of Engineers) and Balcones Canyonlands National Wildlife Refuge (Alliance for the Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018). Texas Parks and Wildlife Department, Lower Colorado River Authority, The Nature Conservancy, and other cities, counties, and conservation organizations also own lands within the breeding range. Land management practices vary, but many of these lands are managed compatibly for this species (Groce et al. 2010, USFWS 2014). In the USA, it is listed on the Federal Endangered species list and has a recovery plan (USFWS 1992, Ladd and Gass 1999), although there is ongoing action within the state of Texas, despite the efforts of the USFWS, to have such Endangered species status removed (USFWS 2016, Doyle 2020). Several regional habitat conservation plans have been approved or are under development (Ladd and Gass 1999, J. Lyons in litt. 1999), including the Balcones Canyonlands Preserve in western Travis County (Alliance for the Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018). Control of invasive species is being attempted in the breeding range, e.g. in Balcones Canyonlands Preserve (W. Reiner and J. Scalise in litt. 2018). Efforts to protect the wintering range include the Alliance for the Conservation of Pine-Oak Forests in Mesoamerica, which was formed in 2003, and consists of institutions located in the United States, Mexico, Guatemala, El Salvador, Honduras, and Nicaragua. The Alliance (2008) developed a conservation plan for the ecoregion with the goal of conserving pine-oak forest habitat. This conservation plan represents the first regional management, conservation, and sustainable development effort for pine-oak forests with the purpose of promoting and sustaining biodiversity, water, timber, recreation, and sustainable rural development (USFWS 2014).
Since the species was listed on the Federal Endangered species list, habitat mapping, population monitoring, and viability analyses have increased our knowledge of species distribution, habitat requirements, and threats within the breeding range (Alliance for the Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018). In 2017, the Department of Defense and USFWS initiated efforts to track movements between the breeding and wintering range using geolocators (Alliance for the Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018). Surveys in 2006-10 and 2014-8 have improved knowledge of its wintering distribution and trends (Alliance for the Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018). Several Private Conservation Banks have been established to protect habitat for the species.

Conservation Actions Proposed
Provide permanent protection of large blocks of breeding habitat (USFWS 2014, Duarte et al. 2016a, C. Harper in litt. 2016). Ensure Endangered species status is retained. Restore connectivity within breeding population to promote gene flow (Lindsay et al. 2006) and maintain local populations (Duarte et al. 2016b), and more generally restore and reforest priority areas throughout its range (e.g. Alliance for the Conservation of the Pine-Oak Forests of Mesoamerica 2017). Protect enough habitat in the breeding, migrating, and wintering habitat to support viable populations (USFWS 2014). Manage habitat throughout the range such that woodland and forest regeneration occurs and persists over the long term (USFWS 2014). Promote sustainable forest management with ecological criteria for firewood and charcoal in natural forests and plantations (Alliance for the Conservation of the Pine-Oak Forests of Mesoamerica 2017). Develop plans for integrated fire management in priority areas (Alliance for the Conservation of the Pine-Oak Forests of Mesoamerica 2017). Implement measures to alleviate threats. Control invasive species that may be impacting this species. Monitor demographic parameters across the breeding range to evaluate population viability over time (Duarte et al. 2016a). Monitor winter distribution and habitat quality. Assess the conditions required to maintain optimal wintering populations (Alliance for the Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018). Evaluate the ecological role of fire and the effects of climate change on pine and oak forests (Alliance for the Conservation of the Pine-Oak Forests of Mesoamerica 2017). Provide education and outreach throughout the range (USFWS 2014), and promote legislation to help protect the species at all scales (Alliance for the Conservation of Pine-Oak Forests in Mesoamerica in litt. 2018).

Identification

12.5 cm. Smart black, yellow and white warbler. Adult male black above with yellow supercilium and cheek-patch split by black eye-stripe extending from bill through eye to rear auricular region where it joins with black nape (Pyle et al. 1987, Ladd and Gass 1999). Wings black with two white wing-bars and fringing to the flight feathers, black chin, throat and streaks down flanks on white underparts. Female similar but olive to gray streaked black on crown and mantle, chin and centre of throat yellow or white surrounded by variable amounts of black mottling along the sides. Immature drab with indistinct streaking and black eye-stripe. Similar spp. Black-throated Green Warbler D. virens, but first-winter female D. chrysoparia has more distinct, dark eye-stripe, no auricular patch, darker, less olive and usually faintly streaked blackish upperparts and no yellow in vent. Voice Multiple songs: the “A” song is a variable and buzzy zee zee zeedee-zee, while the “B” song is lazy-daisy (or variations); numerous other vocalizations (J. Reidy in litt. 2012). Hints Best located by voice in canopy. Forages in mixed flocks in winter.

Acknowledgements

Text account compilers
Everest, J.

Contributors
Alliance for the Conservation of Mesoamerican Pine-oak Forests, Bird, J., Castillejos Castellanos, E., Duarte, A., Emrick, V., Farquhar, C., Harding, M., Harper, C., Hauwert, N., Heger, N., Isherwood, I., King, D., Komar, O., Ladd, C., Lockwood, M., Lyons, J., Molina, E., Murray, J., O'Donnell, L., Peak, R., Pople, R., Reidy, J., Reiner, W., Scalise, J., Sharpe, C.J., Sterling, J., Symes, A., Wege, D. & Westrip, J.R.S.


Recommended citation
BirdLife International (2024) Species factsheet: Golden-cheeked Warbler Setophaga chrysoparia. Downloaded from https://datazone.birdlife.org/species/factsheet/golden-cheeked-warbler-setophaga-chrysoparia on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/12/2024.