几维 is a phonetic rendering of 'kiwi', with 鸟 ('bird') appended to clarify. The name mimics the male's shrill 'kee-wee' call — preserved both in the English loanword and in the Māori original.
mistakes
Don't confuse 几维鸟 (the bird) with 奇异果 / 猕猴桃 (kiwifruit). The fruit was named after the bird by New Zealand growers in the 1950s — 几维鸟 always means the animal.