The three sites are all located at the western end of the island, with two fields on Rue des Vicheries adjacent to La Societe's existing Orchid Fields, and a third close to the cliffs at Pleinmont. The two fields in Rue des Vicheries are both around three vergees in size.
While one has been purchased by La Societe, the other has been donated in memory of Olive Martel (nee Corbin), who lived at nearby Le Douit Farm, by her sons, Geoffrey and Peter.
La Societe president Trevor Bourgaize said the new fields, although both quite small, meant La Societe was able to safeguard more of this important habitat.
'It is not prime agricultural land as it's so wet, however the fields are great for orchids and other marshland plants and all the associated insects,' he said.
'We will probably graze or cut them for hay. By removing the cuttings you reduce the fertility of the soil which stops the dominant grasses overtaking and allows it to become more species-rich.'
It also plans to put an interpretation board in the field if planning permission can be secured.
The area at Pleinmont is slightly larger at just over four vergees and close to the German observation tower known as MP4.
'We have land the other side of Pleinmont but would love to increase our landholding here and safeguard more of the area,' said Mr Bourgaize.
'It's an amazing place for migrant birds, as we have plants like sea radish, which birds love, growing wild here.'
La Societe is currently setting moth traps in the area and representatives from the botany section have been assessing the area to draw up a management plan.
Mr Bourgaize hopes the area might help La Societe fulfil one of its long-term goals.
'We really hope it is somewhere we will see skylarks breeding,' he said.
'We get a lot of migrant skylarks, sometimes in flocks of up to 150 passing through. We would really like one or two pairs to hang around and breed. They really don't like disturbance and here we could have a path through the area.'
The field at Pleinmont was also a cash purchase, this time from an owner from Essex who had inherited it.
It had been on the market a few years ago at a higher price. When it was re-advertised, at a lower price, La Societe decided to buy it.
'We don't have a bottomless pit of money and have to be very careful with our resources,' said Mr Bourgaize.
'However, we are always interested in new land, especially rare habitats like these, if it is ecologically rich or can be easily improved, or if it's strategically placed.'