Phalacrocorax bougainvilliorum


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Phalacrocorax bougainvilliorum
Species Authority: (Lesson, 1837)
Common Name(s):
English Guanay Cormorant
Phalacrocorax bougainvillii
Taxonomic Notes: Phalacrocorax bougainvilliorum (del Hoyo and Collar 2014) was previously listed as P. bougainvillii.

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2014
Date Assessed: 2012-06-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S.
Contributor(s): Engblom, G., Frere, E., Majluf, P. & Roca, M.
Facilitator/Compiler(s): Benstead, P., Calvert, R., Lascelles, B., Sharpe, C J & Symes, A.
This species is suspected to have experienced moderately rapid declines in the past three generations (33 years) and as a result it is classified as Near Threatened.

2012 Near Threatened

Geographic Range [top]

Range Description: Phalacrocorax bougainvilliorum is found along the Pacific coast of Peru and northern Chile. A small population also bred on a short stretch of the Patagonian Atlantic coast of Argentina, but this appears to be ecologically extinct (Bertellotti et al. 2003). From historical times the Guanay Cormorant has been the dominant avian species in the Peruvian Coastal Current in terms of numbers and consumption of marine resources. The population in Peru was estimated as <4 million birds during the period 1909-1920; 21 million were estimated in 1954 and 3.7 million were estimated on the north-central Peruvian coast in 1996 (Zavalaga and Paredes 1999). Mass dispersal, breeding failures and temporary declines have resulted periodically from El Niño Southern Oscillation (ENSO) events, and both fish-stocks and the populations of seabirds that depend on them are adapted to these fluctuations. Although the species is now protected in Peru, fishing for anchoveta is banned, and the guano industry is adequately regulated, there are concerns that this species has been badly affected by the ENSO event of 1998 (G. Engblom in litt. 2003), and that declines now approach 30% over three generations (33 years in this species).

Chile; Ecuador; Peru
Possibly extinct:
Colombia; Panama
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Zavalaga & Paredes (1999) estimated the population at 3.7 million individuals, hence the population is best placed in the band 2,500,000-4,999,999 individuals.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Breeding occurs year round with an egg-laying peak in November-December (on the northern coast of Perú, breeding starts in June). It breeds on offshore islands and remote coastal headlands and feeds exclusively in the inshore environment usually within 3 km of colonies (Zavalaga and Paredes 1999). Unlike other cormorants it is not primarily a benthic feeder but preys mainly on the schooling Peruvian anchovy Engraulis ringens, Peruvian silverside Odonthestes regia and mote sculpin Normanichythes crockeri found in the cold water of the Humboldt Current (del Hoyo et al. 1992, Zavalaga and Paredes 1999).

Systems: Terrestrial; Marine

Threats [top]

Major Threat(s): Historical declines were due to guano exploitation and overfishing of key food sources (del Hoyo et al. 1992). These threats are now managed to some degree. Consumption of birds perhaps represents the biggest current threat with around 20,000 birds taken each year in Northern Peru (P. Majluf in litt. 2007). Another potential cause of population declines in Peru is high predation rates on eggs and small chicks by Band-tailed Gull Larus belcheri. Declines have been particularly evident since the final collapse of the anchoveta stocks in 1974 (del Hoyo et al. 1992).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Several breeding colonies lie within managed guano reserves or in Marine Protected Areas. Closure of the Anchovy fishery has reduced impact of declining food sources. Education and awareness on the importance of the conservation of this species has helped raise its local profile.

Conservation Actions Proposed
Development of a standardised methodology to estimate the population size throughout the breeding range. Evaluate the human consumption of the species in Peru and Chile. Protect important colonies and regulate, or if neccesary halt, exploitation.

Citation: BirdLife International 2014. Phalacrocorax bougainvilliorum. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 31 August 2015.
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