The earliest term for Easter egg in English is pasch egg or pace egg (from pasch referring to the Passover and then to Easter), first recorded in the later sixteenth century. These pasch eggs were coloured hard-boiled eggs given as Easter gifts, and were symbols of the resurrection and new life. The association of a rabbit or bunny with these eggs seems to have begun in Germany. The earliest uses of the term Easter bunny in English appear in the early twentieth century. Thereafter, the Easter bunny played the role of a ‘paschal’ Father Christmas, leaving gifts of chocolate for children and others on Easter morning.

In Australia, the Easter bunny hopped along merrily with other northern hemisphere seasonal traditions, until it became strongly linked with the pestiferous rabbit, which had been destroying the Australian landscape. Enter the Easter bilby. A bilby is a small burrowing marsupial of woodlands and plains of drier parts of mainland Australia. The word is from the Yuwaalaraay Aboriginal language of New South Wales. We have records of two species. The first, Macrotis leucura, is extinct, and was last recorded in the 1960s. Its decline was exacerbated by introduced rabbits, foxes, and feral cats. The second, Macrotis lagotis, is now rare. At some stage the idea arose that the bilby might be an appropriate replacement for the bunny, and that in Australia the Easter bilby should replace the Easter bunny.

It has been suggested that the Easter bilby tradition goes back to the 1970s:

The origin of the Easter bilby is unknown, but one plausible story is that the concept was invented sometime in the late 1970s by a Melbourne Field Naturalist Club with officials delivering chocolates from the Easter bilby to participants at one of their bush camping trips. The Anti Rabbit Research Fund of Australia approached three South Australian confectioners—Haigh’s, Melba and Cottage Box chocolates—to design and produce Australia’s first chocolate bilbies in 1993 as a way of highlighting the damage caused to the environment by the introduced rabbit. Canberra Times, 7 April 2004.

The first reference we have been able to find to the Easter bilby is in the Adelaide Advertiser on 1 October 1991, where it is put forward as one of several possible bunny replacements:

We should promote one of our native marsupials to take over from Easter Bunny. Indeed, what is wrong with having an Easter Potoroo, Easter Wallaby, Easter Bilby or Easter Bandicoot to do the job? Why continue the traditions from another country which popularise an animal that hasn’t anything to do with Australia’s flora or fauna?

Two months later, again in the Adelaide Advertiser (27 November), it is clear that it is the bilby that has won the Easter egg-giving race:

Easter Bunny beware, the Easter Bilby is out to burrow its way into Australian hearts. The proposed National Rabbit Foundation plans to focus the attention of Australian children on the endangered bilby, at the expense of the pest.

The term Easter bilby had arrived in Australian English!