Find the odd number / letters / word from the given alternative.

The odd one out is kiwi. The other three birds, pigeon, crow, and parrot, are all members of the order Passeriformes, which includes over 5,000 species of birds. Kiwi, on the other hand, is a member of the order Apterygiformes, which includes only five species of birds. Kiwi are native to New Zealand and are the only living members of their family. They are flightless birds with long, sharp beaks and feathers that resemble fur.