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The Life of Macaroni Penguins | Attenborough: Life in the Freezer | BBC Earth

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Additionally, fledgling mass and survival rates seem to have a close relationship. In the same study conducted by Horswill et al, it was found that Macaroni penguins fledging with heavier body masses consistently showed higher survival rates than birds fledging with lighter body masses. Because fledging mass of Macaroni penguins is a function of growth rates driven by parent foraging and feeding strategies, variation in fledgling body mass can be attributed to the parents' abilities to forage food for both themselves and their chicks.

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Key Interaction: Overfishing and Reduced Fledgling Survival

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Key Interaction: Overfishing and Reduced Fledgling Survival

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In the study conducted by Horswill et all, both fledging mass and survival rates were lower than the average during 2004 and 2009. This coincides with recorded years in which Macaroni penguin diets switched from being predominantly krill, to predominantly fish (Waluda et al. 2012). In addition, in 2004 the parent birds from Horswill et al study sites were travelling further distances for food. Overfishing causes decreased amounts of krill and fish for Macaroni penguins to bring to their offspring, causing lower body masses.

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Macaroni Penguins typically experience higher mortality rates as fledglings, with mortality rates decreasing as they age.
Data from 10 consecutive breeding seasons between 2003 and 2012, adult and fledgling macaroni penguins at Bird Island, South Georgia, were observed to study survival rates. During the study period, birds typically experienced low and variable survival rates during the first year following fledging, and higher, more stable survival rates from age 1 onwards (C. Horswill et al, 2014). This is likely because younger penguins are more susceptible to predation from large predators such as fur seals and birds of prey.

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Macaroni penguins are known to be monogamous, forming lifelong pairs which return to each other with each breeding season. Their breeding season success rates are also fairly variable from year to year. In a study conducted by T.D. Williams and S. Rodwell in 1992, the variations in return rates and mate fidelity were studied over a number of years. They found return rates of 70% and 73% in 1988 and 1989, respectively. However, in 1987, there was a return rate of 35%. These varying rates affect how many successful hatchlings will be present at the end of the breeding season.

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Increasing global temperatures interact with both of these threats to Macaroni Penguins.

In addition to increased krill fishing operations, a decrease in sea ice also decreases the amount of krill available to Macaroni Penguins. The melting of sea-ice is linked directly to the decline of this major food supply. In the Atlantic Sector of the Southern Ocean, krill have declined by as much as 80% since the 1970s. (Trathan et al, 1998) This is because krill graze on algae that grow below sea ice. With decreased sea ice, there is also a decreased food source for krill.

Decreasing sea ice also interacts with fur seals. Penguins are generally only at risk of predation by seals when in the water. With decreased sea ice for them to escape to, it is likely that the penguins will be less likely to escape their predators. This also makes it more difficult for penguins to return to their chicks with food they have foraged for in the water.

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Increasing krill fishing operations pose a direct threat to the Macaroni Penguin as a species. Krill serves as an important food source, especially during the breeding season. Unfortunately, krill fishing facilities often harvest during the breeding season when the penguins need food for their chicks. A study done on the ability of Macaroni Penguins to compensate for changes in krill concluded that the penguins can change their foraging behavior to compensate, but only up to a point. After this, they will not have access to enough food. (Cresswell et al. 2008)

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Growing competition with fur seals is another risk factor. Prey competition with the seals has previously existed, but with the fur seal population increasing from an estimated 30,000 to 3 million in the past few decades (Trathan et al. 2012), competition has quickly increased. This causes Macaroni penguins to face even more difficulty finding food. In addition to competing with seals for food sources, the seals also block access to breeding sites, which decreases colony growth (Isaksen et al. 1997).

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Managing Krill Fisheries

Fisheries for Antarctic krill are managed in South Georgia in attempt to reduce resource competition with other predators that feed on krill. Additionally, in the summer, krill fisheries are prohibited from all waters surrounding South Georgia and the South Sandwich Islands, and during the winter they must stay at least 30 km and 50 km from the coast, respectively. (Trathan et al, 2014)

Protection of Breeding Islands

The Heard and McDonald Islands are listed a World Heritage Site. Long-term monitoring projects have also been established at many of these islands to further monitor changes in the populations. By protecting breeding sites, the Macaroni Penguins can potentially have higher successes of breeding seasons.

Monitor and Prevent Pollution/Oil Spills

Like all marine animals, ingestion of plastics or other pollutants pose a risk to Macaroni Penguins. Conservation action concerning this issue has been proposed, but not yet acted upon. Eliminating or at least reducing the amount of marine debris in Macaroni penguin ranges will decrease the amount of pollution related deaths.

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Climate change is contributing to the decrease of sea-ice in Macaroni Penguin habitat. On Marion Island in the southern Indian Ocean, a 50% decline in the Macaroni population has been attributed to ocean warming (Trathan et al, 1998).

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K. A. Cresswell, J. Wiedenmann, M. Mangel, (2008)  "Can macaroni penguins keep up with climate- and fishing-induced changes in krill? "

P.N. Trathan, J.P. Croxall, E.J. Murphy, I. Everson, (1998) "Use of at-sea distribution data to derive potential foraging ranges of Macaroni Penguins during the breeding season"

P.N. Trathan, E.J. Murphy, J. Forcada, (2008) "Environmental forcing and Southern Ocean marine predator populations"

O.A.W. Huyser, (2000) "Diet and foraging behaviour of Macaroni and Chinstrap Penguins at Bouvetoya, South Atlantic Ocean"

T.D. Williams, S. Rodwell, (1992) "Annual Variation in Return, Rate, Mate and Nest-Site Fidelity in Breeding Gentoo and Macaroni Penguins"

Horswill, C., Matthiopoulos, J., Green, J.A., Meredith, M.P., Forcada, J., Peat, H., Preston, M., Trathan, P.N. and Ratcliffe, N. (2014), "Survival in macaroni penguins and the relative importance of different drivers: individual traits, predation pressure and environmental variability"

Trathan, P.N., Garcia-Borboroglu, P., Boersma, D., Bost, C.A., Crawford, R.J.M., Crossin, G.T., Cuthbert, R.J., Dann, P., Davis, L.S., De La Puente, S., Ellenberg, U., Lynch, H.J., Mattern, T., Putz, K., Seddon, P.J., Trivelpiece, W. and Wienecke, B. (2014), "Pollution, habitat loss, fishing, and climate change as critical threats to penguins"

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International), B. L. I. (B. L. (2020, September 9). The IUCN Red List of Threatened Species. IUCN Red List of Threatened Species. Retrieved September 26, 2022,

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Most recently assessed for The IUCN Red List of Threatened Species in 2020, the Macaroni Penguin is listed as Vulnerable. This species has remained at this status since it's first assessment in 2000.