Humboldt penguin(Spheniscus humboldti)
Humboldt penguins are medium-sized penguins, growing to 56–70 cm long and a weight of 3.6-5.9 kg. They have a black head with a white border that runs from behind the eye, around the black ear-coverts and chin, and joins at the throat. They have blackish-grey upperparts and whitish underparts, with a black breast-band that extends down the flanks to the thigh. They have a fleshy-pink base to the bill. Juveniles have dark heads and no breast-band. They have spines on their tongue which they use to hold their prey.
Habitat
The Humboldt penguin is a top predator endemic to the west coast of South America. The Humboldt penguin's breeding distribution ranges from southern Chile along the dry and arid coastal regions of the Atacama Desert to subtropical Isla Foca in north Peru. Its range is restricted to the coast and offshore islands affected by the Humboldt current, which provides a continuous supply of nutrients and food, thus supporting huge populations of seabird. In Chile, the most important breeding colony is at Isla Chañaral.
Diet
The Humboldt penguin feeds predominantly on pelagic schooling fish. The consumption of cephalopods and crustaceans vary between populations. Northern colonies consume primarily garfish, whilst southern populations primarily consume anchovy, Araucanian herring and silver-side. There are seasonal differences in the Humboldt penguin's diet that reflect the changes in availability of fish species across seasons.
Breeding
The Humboldt penguin nests in loose colonies, with most pairs laying two eggs of the same size 4 days apart that require 41 days of incubation. Their breeding schedule is adjusted depending on the abundance of food. They breed immediately after moulting, when food is abundant and solar radiation is reduced. The Humboldt penguin lay eggs from March to December, but also with peaks in April and August–September, due to individuals having a second clutch. Half of the females successfully have two clutches per year and most were double broods. If pairs lose their eggs during the first breeding season, they lay a new clutch within 1–4 months. The incubation shifts last, on average, 2.5 days, before one parent takes over and allows the other to forage. There are no differences in the contribution to provisioning from the male and female parents. Chicks hatch generally 2 days apart. Chicks are semi-altricial and nidicolous and guarded by one parent while the other forages. Chicks are fed only once every day. Chicks are left unattended at the nest site after a certain age and both parents forage simultaneously. The historical breeding sites of this species are burrows on guano layers. Nests of the Humboldt penguin can also be found at caverns, hollows, cliff tops, beaches and scrapes covered by vegetation. They also nest at few Peruvian islands where true soil can be found for digging. The majority of penguins breed on cliff tops.
Population
According to the IUCN Red List, they are classed as Vulnerable(VU). A census of the breeding population in Chile carried out in spring 2017, considering all known colonies, suggests that this country holds a population of 5,100 breeding pairs, equating to 10,200 mature individuals. A census of moulting birds, including mature and immature individuals, carried out in January 2017 in Peru, accounted for 13,600 individuals in this country. This roughly equates to a global population of 23,800 mature individuals, though this is considered a maximum value. A current analysis of the population trend reveals high uncertainty in the quality of population numbers taken in the past three generations, with important deficiencies in the coverage of breeding sites and in the methodology employed to count penguins within and between Peru and Chile. Most breeding colonies in Peru declined in numbers between 1980 and 2008. In contrast, some colonies in northern Chile showed a positive trend over the same time period; however, the significant population increase in the largest breeding colony at Chañaral Island was attributed to a considerable underestimation of penguin numbers in the past, and thus likely does not represent a real increase in numbers. Colonies in central Chile showed a stable or negative trend. As a consequence, interpreting the current trend of the global population is problematic and further research is needed. However, considering the lack of evidence for an overall stability or increase in numbers, the current population trend is precautionarily retained as declining.
Threats
The Humboldt Current System has alternating blooms and depletions of productivity triggered by El Niño-La Niña dynamics. During El Niño, prey availability is reduced to penguins, inducing nest abandonment and chick mortality. However, La Niña conditions improve food availability, producing higher breeding success and chick survival. Increased frequency and intensity of El Niño events will likely harm the Humboldt Penguin by reducing its ability to recover fast enough, as has been observed in the Galápagos Penguin. Flooding has been recorded to cause species mortality and a loss of reproductive success in some areas of this species’s range. The high number of artisanal gillnet fisheries operating within the species range is a considerable concern for the species, and may be of greater impact than large-scale fisheries. Industrial fisheries in Peru and Chile exploit the main prey species of penguins (sardines and anchovies). A study demonstrated that the removal of forage fish is an important pressing threat to several seabirds in the Humboldt Current Ecosystem, that may be hindering their ability to recover to pre-industrial fisheries population levels. Gillnets from artisanal fisheries regularly entangle and kill penguins both in Chile and Peru, and penguins have been shown to be caught as bycatch in large-scale trawl, porse-seine and long-line fisheries throughout their range.
Introduced rats (House Rat and Brown Rat) predate unattended eggs at several colonies in north and central Chile and have also been recorded killing chicks in Punta San Juan, Peru. Feral dogs have been reported to kill adults at Pájaro Niño Island in central Chile while feral cats have been observed on some islands with breeding colonies in Peru. Culpeo have been noted to cause considerable mortality in coastal colonies in Peru, while gulls and vultures are typical egg and chick predators. Disturbance impacts may be locally significant for the species. Penguin colonies are frequently visited by tourists and fishermen collecting seafood or seaweeds in northern Chile and Peru. Historical declines resulted from over-exploitation of guano, which greatly reduced the availability and quality of nesting habitat. Removal of guano reduces the preferred substrate used by penguins to dig burrows, but guano miners also increase adult and egg mortality through direct harvest, trampling of nests, direct disturbance to breeding sites and by the introduction of alien species such as dogs and rats. The coastal and marine area around the major colonies in northern Chile (29-30°S) is currently threatened by the construction of coal-fired power stations and large mining proposals. An industrial mega-port has been approved in the bay close to Punta San Juan, the largest colony for Peru. In northern Chile, eggs are collected for local consumption and birds are killed for use as fish and crab bait. There is also the potential for oil spills affecting some colonies. In central Chile, two major oil spills occurred in the period 2015-2016, threatening the colony at Cachagua, which contains 800 mature individuals. Over the longer term, the reproductive success of oiled individuals is likely to be impaired and impacts on the marine environment are likely to impact food resources in concert with climate impacts.
Conservation
Conservation Actions Underway
Colonies in Peru and Chile are monitored regularly. In January 2010, the Peruvian government established the Guano System National Reserve. This network of headlands, capes and islands harbours nesting sites of Humboldt Penguins and protects major foraging areas around them. The San Fernando National Reserve is also a major site for penguins. Monitoring and removal of rodents has recently begun at Punta San Juan. Recently, the Chilean Forest Service eradicated rabbits from Isla Choros in northern Chile, and they have developed an Action Plan for the species aiming to improve its conservation in the country and particularly within the protected area network. Currently, the National Zoo in Santiago (Chile) is successfully developing an ex-situ programme by raising chicks from neglected eggs taken from wild populations. Recently, the Shimonoseki Marine Science Museum (Japan) succeeded in artificially inseminating female penguins from frozen sperm.
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Conservation Actions Proposed
Currently, population estimates for Peru and Chile are determined by different methods and this prevents comparisons and estimates of the global population. Therefore, a consolidated census methodology for both Peru and Chile should be established. Determine the optimum survey times and methods for assessing the population size of the species in both countries (e.g. define whether censuses of breeding or moulting birds [or both] should be conducted for the species). Quantify the impact of identified threats on distribution, abundance, and breeding success. Identify and quantify the impacts of climate change on population size, distribution, and breeding success. Determine basic life history parameters at strategic colonies along the species's distribution, including juvenile dispersal and survival, breeding success and population size. Identify critical areas for conservation, both inland (breeding) and at sea (foraging), and monitor strategic colonies to detect changes in abundance and how colonies behave during periods of food abundance and scarcity. Determine whether the fluctuations in numbers observed during El Niño are caused by mortality, dispersion or a combination of both. Generate relevant information for industrial fishery management and policy (define catch quotas and fishery bans based on ecosystem parameters) and monitor targeted prey species. Generate a baseline of health parameters across the species's distribution. Assess whether the current Marine Protected Area (MPA) system effectively protects penguins, and establish further MPAs around strategic colonies to secure feeding grounds of penguins, at least during the breeding season. At colonies where MPAs already exist, enforcement should be coupled with management plans and measurable objectives, so that conservation practitioners can monitor the efficiency of MPAs and adapt to changes as necessary. It is urgent to reduce bycatch in gillnets along the entire distribution of the species. The industrial anchovy fishery is a threat to Humboldt Penguins, so total allowable catches should be set based on trophic and oceanographic models that include ecological parameters and a precautionary approach, reducing fishing pressure during El Niño years. Implement a sustainable guano harvest method in order to minimize disturbance at the breeding colonies and better preserve nesting habitat. Continue eradication of invasive species, particularly rats. Develop educational programmes on fish and seabird conservation for adults and children to better understand economic and conservation trades-offs with human well-being.