All four species breed in colonies, which can range in size from just a few nesting pairs to tens of thousands of birds.
The larger colonies of macaroni penguins are at Long Beach, Cape Lockyer and West Cape, while the largest king penguin colony is at Doppler Hill (part of which is shown in this photograph).
The population of king penguins is increasing, while there is preliminary evidence indicating decreases in the breeding populations of the other three species. The king penguin population has been increasing since the late 1940s, and is presently doubling every five years or so.
Penguins form the majority of the total seabird biomass on Heard Island. Because of their large populations, king and macaroni penguins are the most important predators of marine resources. The penguins consume a variety of fish species but krill and squid are also taken.
More information can be found on each of the four breeding species of penguin at Heard Island by following the links below.