Bilbies have become an iconic image representing many threatened species in Australia. The long-eared bandicoot used to range over 70% of the country but land clearing, foxes and feral cats have caused a massive reduction in its numbers and range.
The long ears of the bilby and the devastating impact of the European rabbit on Australia no doubt inspired the idea of the Easter Bilby, now promoted by a number of chocolate companies. Rabbit Free Australia http://www.rabbitfreeaustralia.org.au/ own the Registered Trademark and image "Easter Bilby" and they have for years received support from South Australia's Haigh's Chocolates www.haighschocolates.com.au/our_company/environment.html
Darrell Lea chocolates also use the bilby image in Easter chocolate sales and in turn provide substantial donations to the Save the Bilby Fund http://www.dlea.com.au/?Community/Partnership/Save_the_Bilby
However, others use the image without providing any known support to threatened species protection or research. I understand they avoid the Trademark issue by selling their products as Chocolate Bilbies (within their Easter range by not actually "Easter Bilbies") and by simply being too big for a group like Rabbit Free Australia to take on.
So when you buy your Easter Bilbies this year, check the packaging and make sure you support the companies that support threatened species. You'll feel less guilty eating the chocolate that way.