There are numerous birds species in Aru. The avifauna is fairly similar to Kei but with more of an Australian influence. There are two species of birds of paradise observable in Aru and two Manucodes.
Here a mâle Greater Bird-of-Paradise.
The other species of bird of paradise in Aru is the King Bird-of-Paradise that is fairly common in non degraded forest patches.
Aru in contrary to Kei has still huge primary forests and is home to 'bigger'' species like the Southern Cassowary and the same is true for mammals like wild deers, ground cuscus, dusky pademelon and more.
The best season for the Birds of paradise is between July and October and the island is joined by plain from Ambon or by ferry from Kei every week.
to find the entire bird list :
https://www.kasoartravel.com/sites/www.kasoartravel.com/files/uploads/PDF/aru_birds_list.pdf
Aru is much more remote then Kei and if you want to discover the heart of the island and all of the flora and fauna be prepared to sleep in hammocks eat rice and noodles get eaten alive by mosquitoes, it isn't for everyone but trust me it is worth it ! The wilderness is magical and beeing woken up by the song of the Greater birds-of-paradise is truly an amazing feeling
To plan a birdwatching trip in Aru I recommend going to Badi Gaki https://www.kasoartravel.com/fr/content/aru-%E2%80%A2-au-pays-perles-paradisiers
Where you can see Birds-of-paradise in dedicated photographic hides in the canopy. And sleep in a confortable bungalow in the middle of the jungle.
The White-naped Pheasant Pigeon in an endemic bird to Aru, It is an elusive species and there are no pictures of the species in the wild. During my last trip to Aru I searched for it by placing camera traps around the village of Toengwatu but didn't get any results. The species may be extinct in the wild and if you go to Aru, finding it would be a huge accomplishment, The local name of the species