Peruvian pelican

Pelecanus thagus is a pelican of the family Pelecanidae, described by Molina in 1782 ^[1]. It lives only in the Humboldt Current system ^[2] and, together with the guanay cormorant and the Peruvian booby, makes up the trio known as guano birds, although it is the least numerous of the three ^[3]. It is known in Peru as «pelícano peruano» ^[4]. The IUCN Red List classifies it as Near Threatened in its 2018 assessment ^[5], and Peru's official list of threatened wildlife, approved in 2014, places it in the Endangered category ^[6].

Its body is large and bulky, its wings broad and its bill long, carrying the gular pouch typical of pelicans, which cannot be seen while the bird is perched ^[3]. The adult has a dark body with white coverts; outside the breeding season it has a yellowish head and a white neck, and when breeding it keeps the same head but the neck turns black ^[3]. The juvenile is dark with a white belly ^[3].

An adult weighs between 5 and 7 kg ^[7].

It is endemic to the Pacific coast of South America. Its breeding colonies do not form a continuous band but are concentrated on certain coastal islands from Santa Clara Island (3° S) in southern Ecuador to Mocha Island (38° S) in Chile ^[8]. A model built on 4818 records from 2000 to 2015 estimated a potential range of about 466836 km², between 2° 13′ S and 46° 59′ S, with the highest probabilities from northern Peru to central Chile ^[8].

At the southern end of its range, in Chile's Los Lagos region, its presence has grown in recent years. In counts made from boats at three seabird colonies between 40° 55′ S and 41° 48′ S, over the 2013–2014 and 2014–2015 seasons, pelicans were numerous and many were juveniles; the only sign of nesting was an egg laid on bare rock on Caicura Island in December 2013, which had still not hatched by January 2014 ^[9].

In Peru it lives over the cold sea off the coast, mainly between Tacna and Piura, although it has been recorded as far as the northern tip of Tumbes ^[4]. It is found from Foca Island in Piura (5° 12′ S) to the border with Chile, and its last breeding site towards the south of the country is Punta Coles in Ilo (17° S) ^[3]. It nests on islands and headlands, on flat ground with recorded slopes of less than 4°, and also rests on beaches and coastal wetlands ^[3].

It can lay eggs in any month, but does so more often in the austral spring and summer; colony occupation and courtship begin in mid-September ^[3]. The nest is built from feathers, twigs and guano, and the clutch is 1 to 4 eggs ^[3]. Incubation lasts 37 days, chick care about 80 days and care after the first flight another 30 days; towards the end of April adults and juveniles disperse, returning to the colony in September ^[3].

On Lobos de Tierra Island in December 2010, incubation shifts lasted 13.8 hours on average, and 73 % of nest reliefs took place between 07:00 and 10:30 ^[7].

Between January 2023 and April 2024, amid the avian influenza epidemic and with El Niño off the coast, pelicans bred on 6 islands of the guano islands and headlands reserve: Lobos de Tierra, Lobos de Afuera, Macabí, Pachacamac, Chincha Norte and Santa Rosa ^[2]. Breeding peaked from October 2023 to April 2024, with 60 % of birds breeding in December 2023; on Macabí breeding lasted 6 months and on two southern islands only 2 or 3 months ^[2].

Its main prey is the Peruvian anchovy, Engraulis ringens ^[3]. On Macabí Island, regurgitates analysed in February 1986 and April 1987 held mostly anchovies of 14.0 to 18.5 cm, and to a lesser extent other fish such as sardine ^[3]. Every bird tagged on Lobos de Tierra in 2010 regurgitated anchovies when caught ^[7].

A GPS study of 5 incubating adults on Lobos de Tierra showed that 87 % of their trips to sea were strictly nocturnal: they left at dusk or during the night and came back soon after sunrise ^[7]. Trips lasted 11.2 hours on average, the maximum distance from the colony averaged 41.4 km and reached 82.8 km, and the birds flew at about 41.4 km per hour ^[7]. The authors suggest that feeding at night may let them avoid competing with boobies and cormorants, which fish only by day, and note that these pelicans would dive no deeper than 2 m ^[7].

As a high-level predator in the Humboldt Current food web, changes in its numbers mirror what happens at other levels of the ecosystem; its droppings, like those of the other guano birds, also return nitrogen and phosphorus to coastal waters ^[3].

Its global category is Near Threatened ^[5]. In Peru it is classified as Endangered ^[6], and the 2018 national Red Book justifies that category by the steep population crashes that El Niño events cause, made worse by overfishing of anchovy ^[4]. Since 2024 it has been listed in Appendices I and II of the Convention on Migratory Species ^[10], on a proposal by Chile, Ecuador, Panama and Peru ^[3].

Its numbers have swung widely. In 1907, 100000 pelicans were recorded on Lobos de Tierra Island; Peru's population was estimated at 350000 birds in 1953 and reached its highest recorded level, 509000, in 1988, but during the 1997 El Niño it fell from 300000 to 1800 birds ^[2].

Highly pathogenic avian influenza H5N1 was detected in Peru in November 2022 ^[2]. Authorities reported between 39633 and 47414 dead pelicans from November 2022 to May 2023, against 125794 counted in protected areas in August 2022; abundance in marine protected areas fell by 31.5 % to 37.6 %, and in 2023 official counts ranged from 1652 to 46046 live birds ^[2].

Other threats are egg collecting on Lobos de Tierra by small-scale fishers and poaching ^[4]. Pelicans have been documented being caught so their meat can be sold, for instance in Ascope province, La Libertad, as well as dying in fishing nets and from dynamite fishing ^[3]. A distribution model predicts that its breeding range would shrink by about 20 % under the most severe climate scenario, and its authors expect the coast of southern Chile to become an important refuge for the species as the climate changes ^[8].

Not medical advice. For a sting, a poisoning or an allergy, seek medical care.

Samples from pelicans taken on the Peruvian coast from November 2022 onwards confirmed highly pathogenic avian influenza virus H5N1, lineage 2.3.4.4b, which the same study also found in sea lions, common dolphins, guanay cormorants and sanderlings ^[11]. According to the authors, finding the virus in two resident guano birds, the pelican and the guanay cormorant, adds one more way it could eventually reach people, since guano is applied widely as a fertiliser on farmland ^[11].

The H4N5 influenza subtype has been reported as another virus able to affect the species, and Newcastle disease virus has been found in pelican faeces from the Paraíso wetlands ^[3].

As a guano bird, its droppings are part of the guano harvested from islands and headlands as organic fertiliser for farmers; the state programme in charge monitors its populations every month and protects its resting and breeding areas ^[3]. Censuses take place on the first two days of each month on the guano islands and headlands, by mapping the area of each colony and multiplying it by a bird density ^[2].

At the same time, guano harvesting and the presence of fishers on breeding islands disturb its colonies ^[2]. Hunting it is banned in Ecuador, Peru and Chile ^[3].

The main breeding colonies lie within the Guano Islands, Islets and Headlands National Reserve, which brings together 22 islands and 11 headlands along the coast; in 2023 and 2024 it bred on Lobos de Tierra, Lobos de Afuera, Macabí, Pachacamac, Chincha Norte and Santa Rosa ^[2]. According to the 2018 Red Book, it is also present in the Paracas National Reserve and the Illescas Reserved Zone ^[4]. It can be seen resting on beaches and wetlands, and because it flees when disturbed, approaching its colonies leads to lost eggs and dead chicks ^[3].