Protecting threatened Over-seas biodiversity

Do rats eat Madagascar Pond-heron eggs?

In order to reply to this question the GEPOMAY placed false nests and camera-traps during July 2019 to study eventual predation by rats on Madagascar Pond-heron eggs.

Rat in a false nest © GEPOMAY

Study of the impact of rats on the Madagascar Pond-heron

Even if the impact of rat predation on numerous bird species has been demonstrated around the world, to date no study has shown that rats actually predate Madagascar Pond-heron eggs or chicks on Mayotte. So, before taking action to eradicate the rodent the GEPOMAY set-up a two-part study within the Life BIODIV’OM program which would allow demonstrating the impact of rats on the pond-heron.

The 2018-19 season

The main objectives during the first season were to verify that rats were present in the mangroves used by the Madagascar Pond-heron by placing camera-traps and if rats were present to quantify their presence using “WaxTags” and bait in the mangroves.

The 2019-20 season

Although the first year study had shown and quantified rat presence in the mangroves where the pond-heron nests it wasn’t able to show that rats predate their nests. During this second year the GEPOMAY used the artificial nest method to acquire more information on the impact of rats. During June and July 2019 the GEPOMAY placed a total of ten artificial nests in two heronries in two different mangroves. Two hen’s eggs were placed in each one of the nests and camera-traps suitably installed. To be followed…