by Nataly H. Aranzamendi
All species of penguins are restricted to southern latitudes and most of us think of them in cold climates and Antarctic snow. But there are two species that venture farther north, reaching the equator. They are sun-loving penguins: The Humboldt and Galapagos penguins.
Adapted to a sunny life
Penguins split their lives between two landscapes: in ocean waters when searching for their favorite fishes and squid, and on land when it’s time to breed or to change new feathers. The Galapagos and the Humboldt penguins, like other penguin species, are top predators of marine food webs and key elements for the balance of southern marine food chains. Both species live in habitats that look quite harshly similar. The Humboldt penguin likes to nest in guano mounds on rocky shores and cliffs, and similarly the Galapagos penguin likes rocky crevices and protected shelters.
Although these penguins are sun-loving birds, they are still associated to relatively cold temperatures, as their distribution is mainly determined by the presence of the Humboldt Current, a current with cold waters that flow north from Antarctica all the way to the Galapagos. The Humboldt Current is one of the world’s most productive, filled with nutrients which are ideal for plankton and wildlife to thrive.
A lifetime of threats
Both species of penguins have gone through dramatic population fluctuations. In the 18th century, Humboldt penguins occurred by the “hundreds of thousands” before the guano exploitation started. Together with human exploitation and decrease of available habitat, these species have also been negatively impacted by water temperature fluctuations provoked by El Niño, an increase of invasive species, and new wildlife diseases to name a few threats. Here’s a summary of the most relevant facts for each species:
Humboldt penguins (Spheniscus humboldti) used to be abundant in the 18th century. Historical records mention ‘millions of birds’ along rocky beaches in the coasts of Peru and Chile. When the exploitation of guano began, penguins saw their nesting grounds being constantly disturbed and they quickly abandoned those areas. Moreover, their numbers decreased as a result of direct hunting of adults and egg harvesting.
Their current numbers are calculated at around 30,000 individuals (accurate estimates unknown due to deficiencies in survey methodologies). Although population numbers seem stable and/or growing in some years, Humboldt penguins are classified as Vulnerable by the International Union for the Conservation of Nature (IUCN). Sometimes when strong El Niño events hit, they can face years with up to ~60% mortality of individuals. The main reason for such dramatic declines is linked with their favorite prey: Anchovies and other small fishes swim deeper in cold waters or farther away from penguin’s foraging areas when El Niño’s warm waters invade the Humboldt Current. Unfortunately, it is very likely that El Niño events will become more frequent and less predictable in a warming world, endangering the probabilities of immediate recovery for Humboldt penguins.
Industrial fisheries and the risk of entanglement on gill nets pose another threat for this species. Although Humboldt penguins prefer to stay close to their nesting colonies during breeding, non-breeding individuals venture farther away during winter, as has been shown by recent tracking of individuals, increasing the likelihood of encounters with fisheries.
Penguins and their eggs are also easy prey for invasive species. Rats, feral cats and dogs and even human activity have had an effect on nesting populations. Current management programs in the largest colonies of Humboldt penguins include the eradication of such species with preliminary positive results. However, this implies a gigantic amount of work and management programs now run mostly in protected areas and with limited budgets.
The Galapagos penguin (Spheniscus mendiculus) can be found only around two islands in the Galapagos archipelago: Isabela and Fernandina islands. Like its closest neighbor the Humboldt penguin, the populations of Galapagos penguins have experienced dramatic numeric fluctuations (up to 80%) provoked by El Niño events, introduced species, and new diseases.
The threat for this species, however, is potentially more dramatic than the one for the Humboldt penguin, since their numbers do not exceed 5,000 individuals. Due to their restricted geographical location and limited numbers, the Galapagos penguin’s current status by the IUCN is Endangered.
Galapagos penguins are also threatened by local fishing operations and the possible arrival of diseases such as bird malaria. Moreover, climate change may likely decrease the availability of its various fish prey which could possibly limit the chances of successful nests for this bird.
How do we make sure that these species will survive in the future?
Species can persist if coordinated efforts by scientists, authorities, local fisherman and the general public start alleviating pressures coming from human sources. For example, the installation of artificial nests can potentially increase available habitat for both species and increase their chances of yearly nest success.
Similarly, restricting access to breeding grounds for tourists, local fishermen and public in general has been a strategy that has proved successful for many other marine birds for which their nesting colonies have been re-populated. This strategy could also potentially work for these penguins.
An urgent and forceful control of invasive species might have the strongest immediate impact on nesting birds and could boost population numbers and recruitment.
Most importantly, public awareness constitutes a powerful tool for the preservation of any species. It’s crucial to understand the impact of our activities on the world (e.g. fishing, climate change) and the ways to mitigate our negative individual impacts. Hopefully, all these measures implemented could offer a more positive prospect for these sun-loving penguins and one day we might even see thousands of them again enjoying the sun on their rocky beaches.
Have you ever seen Galapagos or Humboldt penguins in the wild? Tell us about it in the comments below.