Data Zone
Justification of Red List category
This species is undergoing a rapid declines owing to continued habitat loss and degradation, and hence it is listed as Vulnerable.
Population justification
The current known population includes important concentrations at Punta San Pedro (70 individuals), Todos Santos (120 individuals), Santiago (up to 150 individuals), San José del Cabo (487-700 mature individuals in 2009; assuming an exponential decline of 30-49% over three generations this would currently equate to 225-475 individuals) and further individuals at other sites in the southern part of the range (Pronatura in litt. 2009; B. Matheson in litt. 2013; R. Rodríguez-Estrella in litt. 2016). In the northern part of the range, only the population at the oasis San Ignacio has been quantified; it is estimated at 250 individuals (Carmona et al. 2020). The total population therefore numbers at least 815 individuals; to account for further populations at occupied sites it is here tentatively inferred as numbering 1,000-2,499 individuals, which equates to 650-1,670 mature individuals.
Despite being restricted to coastal and freshwater marshes for breeding, the species is able to disperse between sites (Erickson et al. 2008; Carmona et al. 2020; Curson and Sharpe 2020). It is therefore tentatively assumed that the species forms two subpopulations, one in the northern part of the range, numbering more than 165 mature individuals, and one in the south, numbering at least 375-540 mature individuals.
Trend justification
This species is suspected to be undergoing a decline owing to severe pressures on Baja California's oases and the resultant conversion of habitat at many sites (Rodriguez-Estrella et al. 1999). Several occupied sites have experienced population reductions and even local extirpations (Ericksen et al. 2008).
Even though the rate of decline has not been quantified, the high pressure on its habitat and evidence of local extinctions suggest that declines are rapid; they are tentatively placed in the band 30-49% over the past ten years.
Geothlypis beldingi has a fragmented distribution on the Baja California peninsula, Mexico. The nominate race is known from at least 15 sites (C. Devenish in litt. 2010) with important concentrations at Punta San Pedro, Todos Santos (B. Matheson in litt. 2016) R. Rodríguez-Estrella in litt. 2016), Santiago (R. Rodríguez-Estrella in litt. 2016) and at San José del Cabo, where the population increased likely due to a chance increase in the quality of habitat (Pronatura in litt. 2009). The race goldmani is now known from at least 12 sites including large numbers at San Ignacio and La Purísima (Rodríguez-Estrella et al. 1999, Erickson et al. 2008). However, despite being relatively common at these site, the area of suitable habitat is probably very restricted (Rodríguez-Estrella et al. 1999). It appears to have been extirpated from at least two sites, El Triunfo and San Pedro de la Presa (Erickson et al. 2008, R. Rodríguez-Estrella in litt. 2016); but, in 2009 up to three adults were present at El Oro. This might be the location referred to as El Triunfo, where the species was collected in 1924 (C. Devenish in litt. 2010). Another small breeding population was recently found at Las Cuevas (Erickson et al. 2008) and San Dionisio (Pronatura in litt. 2009), near Santiago.
It occupies oases of reeds (Phragmites australis) and cattails (Typha domingensis) fringing permanent, lowland, freshwater marshes or rivers, and has been found occasionally in brackish coastal marshes (Curson et al. 1994, R. Carmona in litt. 2020) and recently in at least one newly created marsh in a hotel district, near active agriculture (Erickson et al. 2008). Birds are mostly located within 15 m of the water's edge, and never more than 50 m away from water (Rodríguez-Estrella et al. 1999). The nest is up to 1.5 m above the ground in cattails or tule, and eggs are laid between March and May (Curson et al. 1994). Individuals have been recorded c.200 km from the known breeding range, suggesting that the species is capable of dispersing over reasonably large distances (Erickson and Hamilton 2006).
The oases of Baja California are under high human pressure, especially in the south. Accidental and induced fires, reed-cutting for tourism facilities and house construction, and drainage for agriculture and cattle-ranching have decreased suitable habitat (Rodríguez-Estrella et al. 1999). Individuals are probably vulnerable to stochastic events, with hurricanes frequently eliminating portions of reedgrass vegetation in August-October (Rodríguez-Estrella et al. 1999); however, this may underestimate the species's dispersal capabilities (Erickson et al. 2008), which might make it more resilient to such threats. Nevertheless, although individuals have been observed outside their preferred habitat, the presence of these vagrants does not necessarily imply the possibility to form new populations (R. Carmona in litt. 2020). Urban and agricultural expansion and pressures from increasing human population and tourism developments are leading to a high demand for water and potential abstraction of surface water in the wetlands occupied by the species (R. Carmona in litt. 2020). In addition, groundwater may drop as a consequence of higher drought frequency in the course of climate change (R. Carmona in litt. 2020).
Conservation Actions Underway
Recent surveys have improved knowledge of the species's distribution (Rodríguez-Estrella et al. 1999, Erickson et al. 2008, Pronatura in litt. 2009). The IBA Estero de San José del Cabo, a 42 ha freshwater coastal lagoon at the southern tip of the peninsula of Baja California, incorporates habitat for Belding's Yellowthroat, and was designated as a RAMSAR site in February 2008. Angeles del Estero and Agrupación Ciudadana Ecologista, two small local NGOs in the adjacent town of San José del Cabo, have a history of involvement in the conservation of the IBA. The inclusion of oases in Ordenamiento Ecológico Territorial of SEMARNAT in Mexico provides them with official protection in Baja California Sur state and municipalities that can aid in the protection of this species (R. Rodríguez-Estrella in litt. 2016). As part of the BirdLife International Preventing Extinctions Programme, Species Guardian Pronatura Noroeste are implementing the following actions (C. Devenish in litt. 2010): a conservation area plan for the Estero de San José del Cabo was developed to identify conservation targets, assess the viability of these targets, identify critical threats and develop conservation strategies; research and monitoring is underway to determine current status and threats in the Estero de San José del Cabo Ecological Reserve, and at other sites historically important for the species; clean-up days have been conducted; educational sign boards were erected at the San José del Cabo reserve; two bird festivals have been held and outreach materials have been distributed to local schools, and local bird guides are being trained (86 by the end of 2009) to raise the species's profile and strengthen livelihood links with its conservation. A conservation action plan was published in 2011 (Palacios and Galindo-Espinosa 2011).
Conservation Actions Proposed
Use standardised survey techniques to survey all potential nesting habitat in Baja California Sur and adjacent south-eastern Baja California, identifying potential new locations using satellite imaging. Conduct a thorough census of each site by counting singing males in spring in order to ascertain the current population, and repeat at regular intervals to detect local and regional trends. Conduct a formal dispersal study in order to design long-term management actions for the Belding's Yellowthroat metapopulation system. Undertake genetic studies to address questions concerning such issues as the validity of recognising two subspecies or the genetic consequences of population patchiness and potential bottlenecks (Erickson et al. 2008). Incorporate marsh creation into plans for the development of golf courses and resorts within this species's range (Erickson and Hamilton 2006, Erickson et al. 2008). Prohibit burning and cutting of the water-edge vegetation at all sites (Rodríguez-Estrella et al. 1999). Initiate a public awareness programme. Implement an education and outreach programme on the importance and environmental services of the watershed at San José del Cabo. Promote bird tourism to generate income for protecting key sites. Increase the capacity of San José del Cabo in water treatment and quality monitoring. Ensure an adequate supply of water to the oasis at San José del Cabo through water rights. Promote better cattle ranching practices and law enforcement (C. Devenish in litt. 2010).
14 cm. Yellow-olive, masked bird. Yellow-olive upperparts and crown with narrow sulphur fringe bordering black mask. Bright yellow underparts, washed ochraceous on flanks. Female lacks mask and has olive head with pale eye-ring and pale buff supercilium. Yellow underparts, washed brown on flanks and becoming white on belly. Pinkish legs. Black bill. Subspecies goldmani is duller overall with more olive upperparts and brownish wash on flanks. Border behind mask is more whitish in males. Similar spp. Common Yellowthroat G. trichas is smaller with pink on lower mandible. Males have grey border to mask (some G. trichas can have yellow border). Females duller with more indistinct facial pattern. Voice Song is rich, powerful series of phrases. Harsh tchech call.
Text account compilers
Hermes, C.
Contributors
Bird, J., Calvert, R., Capper, D., Carmona, R., Danemann, G., Devenish, C., Erickson, R., Hernández Álvarez, A., Howell, S., Isherwood, I., Khwaja, N., Marrón, G., Matheson, B., Pople, R., Pronatura, Reyes Bonilla, H., Rodríguez-Estrella, R., Sharpe, C.J., Symes, A., Taylor, J. & Westrip, J.R.S.
Recommended citation
BirdLife International (2024) Species factsheet: Belding's Yellowthroat Geothlypis beldingi. Downloaded from
https://datazone.birdlife.org/species/factsheet/beldings-yellowthroat-geothlypis-beldingi on 26/12/2024.
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 26/12/2024.