Status (IUCN v3.1)
The number of breeding pairs has been estimated to be around 11 million breeding pairs (Woehler 1993 as cited by Williams 1995). The population has been cited as decreasing for the last 36 years, although the IUCN has been noted that this conclusion was based on small scale data.
Macaroni Penguins are threatened by commercial fishing (accidental bycatch or harvesting of aquatic resources needed by the penguin), oil pollution, human use of biological resources, ocean warming and severe weather
The potential threats to the Macaroni Penguins are considered to be general threats facing all aquatic species living in the South Oceans. Thus, conservation of the Macaroni Penguin would benefit from joint conservation of other South Ocean species.
Currently, long term conservation actions are aimed at protecting the breeding grounds of the penguins. For example, Heard and McDonald Islands are protected as a World Heritage Site. However, more large-scale data is needed to accurately assess the population status of the Macaroni Penguins. Additionally, current population monitoring projects should continue.
Adult: The head, chin, and throat are black; golden-yellow plumes on the head beginning about 1 cm behind the bill and projecting backwards and horizontally; body and tail are bluish black when new and turn brown over time; underparts are white and separated from the black throat with a sharply angled line from either side of the throat; flipper with a blue-black dorsal edge and a white ventral edge with black tip.
Juvenile: At 2 years, the head plumes are still smaller than adults, but non-breeding 3 and 4 year-olds are indistinguishable from breeding adults (5-6 year olds).
Chick: Fledglings and 1 year-olds have absent or sparse head plumes; chin and throat that are dark grey.
The males and females are fairly similar, although females are slightly smaller in size (including bill size and weight).
Average Arrival Date: October 8
Average Egg Laying Date: October 28
Incubation Period: 35 days
Chick Rearing Period: 30 days
Fledging Period: January 17 – February 23
Average Annual Reproductive Success: 0.40chicks/nest
Nest: The nest is usually dug out of the mud or gravel as a shallow scrape and is lined with a few small stones. Some birds on South Georgia have been known to nest on grass.
Age at First Breeding: 5 years
Egg Weight: 93 grams
Egg Length: 6.9 cm
Egg Breadth: 4.9 cm
Molt: The birds will undergo a pre-molt foraging trip lasting around 14 days in males and 12 days in females. They will increase their body weight by 50-70% during this time. Molting begins at sea about 3-5 days before they return to the colony around the first half of March (immature birds will molt earlier, around January-February), resulting in a total molt-time of 25-35 days.
The vast majority of their diet–at least 70%, and up to 98% depending on the region–is composed of crustaceans (Euphausia spp.). At Heard Island, where less of the diet is composed of crustaceans, about a quarter of their diet is composed of fish.
Skuas, sheathbills, Kelp Gulls and Giant Petrels prey on eggs and chicks; Antarctic Fur Seals and Leopard Seals prey on adults at sea.