Metaphorical artificial ecosystem with resurrected birds - synthetic voices of extinct birds together with their higher or lower pitched artificial relatives are played automatically by Conway's Game of Life cellular automaton (initial state of the automaton is random and each cell is inhabited by one kind of bird, number of active cells changes the speed of evolution)

The birds featured in the piece are birds from all over the world and from various different habitats that went extinct mostly during 20th century and were chosen mostly for availability of archival recordings of their songs.
Instead of original recordings, synthetic remakes and approximations of their voices were used.

Sounds of Dusky Seaside Sparrow (Ammospiza maritima nigrescens), Northern Ivory-billed Woodpecker (Campephilus principalis principalis), Bachman's Warbler (Vermivora bachmanii), Kauai Oo (Moho braccatus) and Poo-uli (Melamprosops phaeosoma) together with two birds now extinct only in the wild, Hawaiian Crow (Corvus hawaiiensis) and Spix’s Macaw (Cyanopsitta spixii), are based on archival recordings.
Sounds of The Huia (Heteralocha acutirostris) and North Island piopio (Turnagra tanagra) are based on human imitation by an earwitness.
Sounds of Heath hen (Tympanuchus cupido cupido), Carolina parakeet (Conuropsis carolinensis) and Great auk (Pinguinus impennis) are adapted from sounds of their closest living relatives (Greater Prairie Chicken, Mitred Parakeet and Razorbill).
Passenger pigeon (Ectopistes migratorius) left only a musical notation, so his song is played (rather ironically) on piano.



sounds of the birds are based on:
recordings from Macaulay Library (https://macaulaylibrary.org): Dusky Seaside Sparrow by Robert C. Stein, 1963 (Macaulay Library ML15073), Northern Ivory-billed Woodpecker by Arthur A. Allen, 1935 (Macaulay Library ML6784), Bachman's Warbler by Arthur A. Allen, 1954 and 1959 (Macaulay Library ML10716, ML10717), Kauai Oo by Robert Shallenberger, 1975 (Macaulay Library ML6031), Poo-uli by Doug Pratt, 1975 (Macaulay Library ML5125), Hawaiian Crow by William V. Ward (Macaulay Library ML13434) and Spix’s Macaw by Bret Whitney, 1991 (Macaulay Library ML57774, ML57099); McPherson Natural History Unit Sound Archive (www.archivebirdsnz.com): The Huia and North Island piopio imitation by Henare Haumana, 1952 (accessible at nzbirdsonline.org.nz); https://xeno-canto.org: Greater Prairie Chicken by Ross Gallardy, 2019; https://avocet.integrativebiology.natsci.msu.edu: Mitred Parakeet by Pamela C. Rasmussen, 2008; wikipedia.org: Razorbill by Lawrence Shove, 1965; musical notation of Passenger pigeon vocalization by Wallace Craig, 1911.