The green, flightless, nocturnal parrot becomes the first bird in the competition's history to score a repeat win.
It first won Forest & Bird's annual Te Manu Rongonui o Te Tau / Bird of the Year competition in 2008.
The critically endangered birds used to live throughout Aotearoa, but today they only survive on predator-free islands.
"There were only about 50 birds in the 1990s and they've been saved by intensive conservation efforts. Today there are 213 individuals," spokesperson for Bird of the Year, Laura Keown, said.
"This is the first time any bird has won the Bird of the Year title more than once, so New Zealand's mighty moss chicken can add yet another feather to its cap."
Voter fraud was discovered during the competition when volunteer scrutineers from Dragonfly Data Science found 1500 votes cast around 3am from the same IP address, all for the smallest (and cutest) kiwi species, kiwi pukupuku / little spotted kiwi.
Infamously, the humble but polygamist hihi attracted the endorsement of Adult Toy Megastore as well as that of the Deputy Prime Minister, the Phoenix Football Team, and the Central Pulse Netball Team.
There were 55,583 validated votes cast in 2020, up from 43,460 in 2019, and the most ever received in the competition's history.
Top 10 winners with instant run-off preferential voting applied:
1. Kākāpō
2. Toroa/antipodean albatross
3. Kakaruia/black robin
4. Kārearea/New Zealand falcon
5. Kererū
6. Pohowera/banded dotterel
7. Kākā
8. Ruru/morepork
9. Whio/blue duck
10. Pīwakawaka/fantail
