[1] The species name waewaeroa is from Māori waewae - "legs", and roa - "long", referring to the elongated hind limbs.

[4] The fossils of Kairuku waewaeroa were found within the Glen Massey formation (34.6–27.3 Ma) in the North Island of New Zealand.

[3] Unnamed species called Glen Murray fossil penguin is estimated to have a height 2 to 20% taller than K.

[4] Additionally, all known specimens of K. grebneffi are larger, although small sample size prevents that from being a diagnostic characteristic.

[7] K. grebneffi lived in what is now New Zealand late in the Oligocene period, roughly 25–27 million years ago.

[6] It is believed that these rock outcrops provided safe breeding grounds and easy access to rich food resources in the surrounding seas.

[7] The cause of K. grebneffi's extinction is unknown, but was probably related to "the drastic change in paleoenvironment" according to Tatsuro Ando, one of the scientists who classified the penguin.

[6][11] In February 2012, an international team of scientists led by Fordyce and Daniel Ksepka reconstructed a K. grebneffi skeleton using a few "key specimens" from the Kokoamu Greensand of the North Otago and South Canterbury districts of New Zealand.