This chapter investigates how media historical transformations in the decades after the Second World War affected radio art and sound poetry and, especially, their (re)presentations of humans and animals. Apart from new sound technologies (e.g. the tape recorder), information technology and cybernetics are crucial here, not least in promoting an ‘ecologisation’ (Erich Hörl) of thinking and being, which problematises anthropocentrism and subject-object configurations. Instead, there is a transition to relationality and immersion. In this chapter, the potential of sound for staging and exploring such a transition is investigated and underlined through analyses of radio art and poetry by Swedish artists and poets Åke Hodell and Öyvind Fahlström, partly framed by a discussion of Samuel Beckett’s early radio play, All That Fall (1956). In the Swedish works, attention is paid to birds and their calls primarily, but also to other sounds, which displace the human voice and gaze as organising agencies and establish a more diffuse and open acoustic space and time. The latter is designated as a ‘posthuman sound ecology’, which stresses not only the sonic presence of other beings, but also a poetically shaped and playful transmutation of the established, almost naturalised, hierarchies and relations between humans and non-humans.