Picaflor de Arica

Picaflor de Arica is a Natural Monument in northern Chile's Arica y Parinacota Region, established in 2019 to protect the Critically Endangered Chilean woodstar hummingbird (Eulidia yarrellii), known locally as the picaflor de Arica. ^[1] The protected area covers 10.8 hectares of riparian and thorny-forest habitat in the Chaca valley (Quebrada de Chaca), approximately 65 km east of Arica via the CH-11 highway, where key nesting and foraging sites are found. ^[2] With an estimated population of approximately 300–316 individuals, the Chilean woodstar is one of the most threatened hummingbirds in the world, and this monument represents the primary government response to the species' acute conservation need. ^[3]

The Chilean woodstar (Eulidia yarrellii) is the monument's defining species, measuring only 7.5–8 cm in length — the smallest bird in Chile — with males displaying a striking purple-violet gorget. ^[1] The species inhabits riparian thickets and gardens in the Azapa, Lluta, Vitor, and Camarones valleys within a narrow latitudinal range around Arica. The hummingbird depends critically on flowering plants for nectar, particularly native Tecoma fulva and garden ornamentals. The main sympatric competing hummingbird is the Peruvian sheartail (Thaumastura cora), which first appeared in Chile in 1971 and is now more common than the Chilean woodstar in the Azapa valley; competition from this species is considered a significant threat to the woodstar's survival. ^[1] The riparian corridors also support Peruvian pelicans, Inca terns, and various resident and migrant landbirds.

The monument protects a relict oasis and riparian vegetation in one of the world's driest desert regions. The protected ecosystem is classified as Interior Tropical Thorny Forest (Bosque Espinoso Tropical Interior), characterized by chañar (Geoffroea decorticans) and algarrobo blanco (Prosopis alba), which provide critical nesting sites and shade for the hummingbird. ^[1] Tecoma fulva provides critical nectar resources and is the focus of restoration planting efforts. Native riparian plants in the broader valley system include Tessaria integrifolia, Pluchea chingoyo, and Phragmites australis reed beds. Invasive tamarisk (Tamarix spp.) and various agricultural plants have altered native riparian structure in many valley sections. The adjacent Atacama Desert is essentially plantless except for isolated lomas communities on coastal slopes.

The protected areas lie within the hyperarid Atacama Desert, one of the driest non-polar regions on Earth. The Chaca valley cuts through the Coastal Cordillera and the western Andean foothills, exposing Precambrian basement rocks overlaid by Mesozoic marine sediments and Cenozoic volcanic material from the high Andes. The Azapa and Lluta valleys are antecedent river valleys that have incised through uplifted terrain, maintaining their courses as the Andes rose. Alluvial fans and terraces along the valley floors provide the substrates for agricultural oases that sustain the hummingbird's habitat. The extreme aridity results from the Andes rain shadow, cold Humboldt Current upwelling, and stable subtropical high-pressure systems.

The Arica area records some of the world's lowest rainfall, averaging less than 1 mm per year in the city itself. Mean temperatures range from 14°C in winter to 22°C in summer, moderated by the cold Humboldt Current. Persistent coastal fog (camanchaca) occasionally provides moisture to coastal slopes but rarely penetrates the interior valleys. The Bolivian Winter (invierno boliviano) brings episodic afternoon thunderstorms to the high Andes between December and March, occasionally generating flash floods in valley bottoms. Winds are generally light, with sea breezes common in afternoons. The exceptional aridity and thermal stability make the area one of the most extreme desert climates in South America.

The Azapa and Lluta valleys have been continuously inhabited for over 9,000 years, making this one of the longest settlement sequences in the Americas. Pre-Inca cultures including the Chinchorro (famous for their mummification practices), Tiwanaku-affiliated groups, and later the Inca Empire maintained agricultural oases in the valleys using sophisticated irrigation systems fed by Andean rivers. Spanish colonizers founded the city of Arica in 1541, and the valleys became important supply routes for silver mining operations in Potosí. Following the War of the Pacific (1879–1884), Arica and its hinterlands passed from Peru to Chile. The valleys remain productive agricultural areas; however, the intensification of agriculture from the 1960s onward, with widespread pesticide use, is linked to sharp declines in the Chilean woodstar. ^[1]

Picaflor de Arica Natural Monument was formally established on May 23, 2019 (published in the Diario Oficial), following approval by Chile's Ministerial Council for Sustainability in October 2018. ^[1] The designation was a direct response to scientific documentation of the Chilean woodstar's catastrophic population decline — from approximately 1,539 individuals recorded in 2002 to only 316 in a 2017 survey, a loss of nearly 80% in 15 years. ^[1] The monument is integrated into the National System of Protected Wild Areas of the State (SNASPE) administered by CONAF, and represents the first unit in a planned network of micro-reserves for species recovery. Conservation programs include habitat restoration with native flowering plants, community education, and population monitoring.

A 500-metre Sendero Picaflor de Arica trail within the monument provides access to the core habitat in the Chaca valley. ^[1] Birdwatching excursions to the Azapa Valley, where the species has historically been most reliably observed at flowering Tecoma shrubs, are the primary visitor draw; early morning hours offer the best opportunities. The Lluta Valley provides additional habitat patches for the species. Arica's coastal attractions, including the historic Morro headland and Chinchorro mummy exhibits at the regional museum, complement a visit. The broader Arica y Parinacota Region offers access to Lauca National Park and the high Andean altiplano with flamingo-studded salt lakes.

Arica city serves as the base for visiting the monument, with well-developed hotel, restaurant, and transport infrastructure. The city is accessible by air with regular flights from Santiago or by road on the Pan-American Highway. Rental cars and guided birdwatching tours are available in Arica. The Chaca valley is reached via the CH-11 highway. CONAF has developed an Environmental Education and Park Guard Shelter Center at the monument, opened after a 16-year gap, funded by the Regional Government. ^[1] Groups are accepted by prior arrangement with CONAF. The Arica San Miguel de Azapa Museum provides archaeological context for the region.

The Chilean woodstar is classified as Critically Endangered by the IUCN, with the population having declined from approximately 1,539 individuals in 2002 to around 316 in a 2017 survey. ^[1] Key threats include agricultural pesticide use that destroys the insects and flowers the bird depends upon, habitat loss from urban and agricultural expansion in the valleys, and competition from the Peruvian sheartail (Thaumastura cora), which expanded into Chile from the 1970s and now vastly outnumbers the woodstar. ^[2] Hybridization between the two species has been documented, raising concerns about genetic swamping. CONAF and BirdLife International–affiliated Chilean ornithological organizations collaborate on population monitoring, nest protection, and pesticide reduction outreach with valley farmers. Habitat restoration planting of native flowering species, particularly Tecoma fulva, has been implemented at several sites. The monument's small size (10.8 ha) relative to the species' mobility requires landscape-scale conservation cooperation across the entire valley system.