SOME of the old faces have disappeared and new feathered residents have moved into Maribyrnong Valley.

Now local environment group Friends of the Maribyrnong Valley is updating the guide to Maribyrnong's avian inhabitants, Birds of the Maribyrnong Valley, first published in 1988.

Member John Upsher said urban development and environmental changes in Maribyrnong and across Victoria had changed the types and numbers of bird species in the area.

"A few birds have gone and a few have come in."

Mr Upsher said the greatest threat to avian diversity was urban development encroaching on habitat.

"Some birds can put up with the urban environment, but others, like the sea eagle, like their own space and would probably go away if there was a lot of development."

To produce a new book that truly represents the current bird population, FMV is surveying representative areas within the valley.

The first surveys will be conducted this Sunday in Brimbank Park, Keilor East, near the Leaping Lizard cafe, and around Pipemakers Park in Maribyrnong.

Experienced bird watchers and volunteers with local knowledge are welcome.

Details: John Upsher on 93177148.