Landau, February 2, 2025
Census of the Moulting Population
For over 20 years, the NGO Acorema has been counting the Humboldt penguin population during the moulting season at the most important nesting sites in Peru. In October 2024, the NGO reported to the “National Service for State Protected Natural Areas (SERNANP)” and the “National Reserve System for Islands, Islets and Guano Islands (RNSIIPG)” on the count during the moult in early 2024 (1). The authors summarize the results as follows: “The annual census of the Humboldt penguin (Spheniscus humboldti) was conducted between January 14 and 27 2024 at 40 sites along the Peruvian coast. The aim was to continue the evaluation of the population development of the endangered species. The survey took place during the moulting season and was conducted according to the recommendations of the 1998 Humboldt Penguin Population and Habitat Quality Workshop. The number of penguins counted was 5,035, which equals a 70% decrease compared to the 2022 numbers (from 15,663 to 5,035 penguins), comparing the sites counted in both years. Most Humboldt penguins were counted on San Lorenzo Island (580), Macabí Island (538), the San Juanito North Island-Little Island archipelago (497), Pachacamac Island (405) and Pescadores Island (338). For the first time since these surveys began in 1999, Punta San Juan has not been among the places with the largest colonies. In 2024, only 270 penguins were counted there. The number of penguins on Santa Rosa Island (48) remained low and has undergone an alarming decline since 2014, when it peaked at 4,939 penguins. The use of drones continues to be important to supplement the direct counts by the census teams.
In 2024, the oceanographic conditions were shaped by El Niño (2). The increased temperatures, together with the outbreak of bird flu in 2023, may have contributed to the very low population numbers. It is therefore important to continue surveys along the coast in the future as well to monitor population trends and conservation status. However, Humboldt penguin populations should not only be assessed in the context of high temperatures caused by El Niño, but also regarding annual landings by fisheries as well as the development of human activities near the colonies.”
The authors emphasize that the decline affects all 36 or 41 nesting sites. The only exceptions were Puerto Inka (3 to 3), the island center of Ballestas (increase from 7 to 85 birds) and the island center of Chinca (increase from 8 to 10 individuals). The researchers also point out that the figures do not show any significant shifts between the breeding islands along the Peruvian coast.
The researchers assess the sharp decline as follows: “Within 26 years in which standardized counts were carried out during the moult, the number of Humboldt penguins in Peru fluctuated between 2,000 and 20,000 (McGill et al., 2004, 2013; McGill, unpublished data). These fluctuations in total numbers are due to both biological and methodological reasons.”
In the conclusions, the authors address disturbances as well as the importance of protected areas:
“2. Since the 2016 surveys numerous activities that disturb or harm penguins have been observed. At several sites the presence of kayaks, bathers or people camping on the beach has been recorded.
The problem is particularly serious on the island of Asia. There, many people in kayaks and bathers were observed approaching or swimming towards groups of penguins. The birds reacted by quickly climbing onto cliffs and scattering.
During the survey on Homillos (tip and island), small fishing boats, kayaks and people fishing near groups of penguins were observed from the shore. Later it turned out that the kayakers were coming from Honoratos, where camping sites had been set up on the beach. There have not been any Humboldt penguins on Honoratos since the mid-1990s.
In 2017, fishermen were observed on the islands in Farallones and San Francisco. The number of penguins was particularly low there.
Also in 2017 and several times since then, fishing nets were recorded hanging from the cliffs in two places on the Ocoña coast.
In general, human activity near the colonies has increased since 2000 due to the highway connection.
3. The importance of protected areas, guano islands and Guano sites as well as some other areas should not be overlooked. As mentioned above, in 2014 - the year penguin populations peaked - 87% of penguins were concentrated in protected areas, rising to 91% in 2024. Within just 1-3 years, the number of penguins can drop from 500 or more to zero in areas without any legal protection or with severely restricted access. Overall, the variance found in unprotected sites can be as high as 15-20 % of the population. As protected areas are very important for the population, unprotected sites must at least be monitored.”
How can the sharp decline be classified?
The researchers Dr. Ursula Ellenberg (New Zealand) (3) and Dr. Guillermo Luna-Jorquera (Chile) (3) warn against jumping to conclusions and point out that
1. Humboldt penguins in poor condition may postpone moulting until they are sufficiently fit to moult successfully, and that they may
2. move hundreds of kilometers south during El Niño to find better hunting conditions in cooler waters. They might then - if they do not moult initially - do so in undisturbed locations further south (4). Unfortunately, no such observations are known.
It can therefore be assumed that not all birds were recorded in the census at the beginning of 2024, as they did not moult and/or moved to cold waters. The losses would then be lower. With a “medium optimism” of losses of 30% instead of 70%, the Peruvian population would then count 10,964 instead of the 5,035 individuals determined.
Regarding the other source of danger, the bird flu, Dr. Ursula Ellenberg points out that other penguin species that breed closer together than Humboldt penguins have proven to be relatively less susceptible to bird flu. She also points out that the timing of the last El Niño may possibly be seen as a “stroke of luck”. As most penguins did not breed, the risk of contracting bird flu was also reduced. For example, Dr. Alejandro Simeone's research group did not observe a single penguin with signs or symptoms of bird flu during fieldwork in November 2023 (4).
Researchers in Chile and New Zealand (3) are concerned about the current development of the population, but emphasize that many questions about the population and its decimation remain unanswered and that it is not certain how much the Humboldt Penguin population has actually been reduced. In this critical situation, they recommend carrying out new censuses in Chile and Peru when the food supply is better. Dr. Alejandro Simeone (5) and Dr. Carlos Zavalaga (6) intend to do this in the short term during the next breeding season. They plan to count the breeding pairs on all important Chilean and Peruvian breeding islands in April and May. With this timed and methodically coordinated survey the number of breeding pairs in the entire population would be determined for the first time.
Humboldt penguins have adapted to the extreme conditions of El Niño and the Southern Oscillation (ENSO) (2) over thousands of years. However, overfishing, bycatch, pollution (including the detection of heavy metals in bones and claws) and now climate change have upset the survival strategy of Humboldt penguins.
Unfortunately, in view of the heavy losses in the last two years, it cannot be ruled out that the risk of extinction has increased considerably and the endangerment level may have to be corrected from “vulnerable” to “endangered” or even “critically endangered”.
W.K.
translated Angelika Veelken
Annotations:
(1) Acorema. October 2024. informe final del estudio: Censo de pingüino de Humboldt enprincipales sitios de Perú. 2024 (Final report of the study: Census of Humboldt penguins at the main Peruvian sites. 2024).
(2) El Niño and the Southern Oscillation (ENSO) describe a complex coupled circulation system of the earth's atmosphere and ocean currents in the equatorial Pacific. El Niño tends to represent the oceanic relationships, while the Southern Oscillation stands for the atmospheric relationships.
(3) Chilean and New Zealand researchers
- Dr. Alejandro Simeone, marine biologist, teaches and researches at the Faculty of Life Sciences at the University Andrés Bello in Santiago, Chile.
- Dr. Guillermo Luna-Jorquera, marine biologist, teaches and researches at the University Católica del Norte, Center for Ecology and Sustainable Management of the Ocean Islands in Coquimbo, Chile.
- Dr. Ursula Ellenberg, ecologist with experience in terrestrial and marine systems, teaches and researches at the University of Otago, Dunedin, New Zealand.
- Dr. Thomas Mattern, marine biologist with a focus on behavioral research of penguins and other seabirds, teaches and researches at the University of Otago, Dunedin, New Zealand.
(4) Personal communications 2024 from Dr. Ursula Ellenberg and Dr. Guillermo Luna-Jorquera.
(5) The survey is part of the Sphenisco-funded research project „Deciphering the population size and foraging behavior of Chilean Humboldt penguins“.
(6) Dr. Carlos Zavalaga, Scientific University of the South, Marine Ecosystems Research Unit, Marine Birds Group, Lima, Peru.
