Tanya Ashken produced multiple versions of 'Kotuku', of which this is the bronze. There is also a 'Silver Kotuku' (1965), cast in aluminium.

Ashken's complex formalism, Gallery Fe29 has suggested, was "[i]nspired by Brancusi (whose Paris studio she stumbled upon late one afternoon in 1961)... [Ashken] reveals a constant artistic struggle to inter-relate concept and form and to shape what emerges ... Her challenge – to give performance and solidity to the constantly evolving, moving and changing effects of nature. The result – ideas abstracted into essential form, encouraging the viewer to let the eye travel through the line of the work and beyond." 'Kotuku' is an elegant example of this activation of viewing where we can both see, and not see, the poise and grace of the White Heron.