Board Game Arena

Was playing a game where we both supported some non-base projects (australia release and aquatic) but they both got removed as more non-base projects were added.

Later in the game, I played a bird with the scavenging ability, and it retrieved these projects so they could be supported again.Is this what is meant to happen?

Yes the rules say that any non base conservation projects go to the discard pile. So if one has been removed and you have a scavenging ability you can pick it up and play it again