Butterfly hunters on trail of elusive Eltham copper butterfly across Victoria

Colonies of the rare Eltham copper butterfly have been found in parts of Victoria. (Supplied: Elaine Bayes and Damien Cook)

The story of the Eltham copper butterfly, according to Central Victoria ecologist Elaine Bayes, is one of lost and found.

The butterfly was first surveyed in 1951, having been collected from several sites around Eltham between 1923 and 1956.

But a subsequent lack of records over the next 37 years combined with housing development in areas where they once thrived — Tallarook, Murtoa, Dimboola, Keilor, Broadmeadows and Yarrambat — led environmentalists to believe the butterflies were extinct.

Back from the abyss

However, the butterflies were then rediscovered at Eltham in 1987 on a property that was about to be subdivided.

The discovery triggered a state-wide search, and nine colonies were found in 1988, including in two new regions: in Castlemaine and Salisbury West in Central Victoria and in Kiata in the Wimmera.

"I'd love to change their name because it's found quite widely, particularly in Castlemaine and Bendigo, where we are finding small populations of them," Ms Bayes said.

The Eltham copper butterfly relies on plants and ants for food and protection at the caterpillar stage. (Supplied: Elaine Bayes and Damien Cook)

"They're delicate … only 20mm wide.

"The girls' maximum survival is 11 days, and the boys [can survive] 28 days.

"They only fly in November and December and a bit in January. And only when it's between 25 and 35 degrees, and only when it's not windy."

The underside of the Eltham copper butterfly's wings are not as striking.  (Supplied: Elaine Bayes and Damien Cook)

Collective effort to save butterfly

Ms Bayes said finding where the rare species lived was the first step in conserving it, but efforts were now turning to protecting the species from threats.

Ms Bayes, ecologist Karl Just and a team of citizen scientists have been conducting surveys of the Eltham copper butterfly in Northern Victoria since 2009, and will now spend the next six months surveying around Castlemaine, Chewton and Kiata.

Ms Bayes said that since 1988, three known populations were lost through housing development at Montmorency, Lower Eltham Hills in Melbourne's outer northern suburbs, and from grazing and weed invasion in Salisbury.

In 2011, eight new populations with between 50 to 100 butterflies each, were found during a 3,000-hectare search across Bendigo, Castlemaine and Wail.

Ms Bayes said it was now up to everyone, including private landowners, to help preserve the species.

"Because even not finding them is useful because it means I, or others, don't have to go and look there."