(saxicola axillaris)
The taxonomy of Stonechats is complex with varies authorities having differing views on species and sub-species. HBW lists three sub-species of Stonechat in Madagascar but considers them all to be sub-species of Common Stonechat (saxicola torquata). Other authorities consider there to be a full species called African Stonechat and consequentially all the African, including Malagasy, forms are sub-species of African Stonechat (saxicola axillaris).
Of the three sub-species occuring in Madagascar the most common is ssp sibilla. So depending on your point of view, the birds in these images are either saxicola torquata sibilla or saxicola axillaris sibilla. In Madagascar these are fairly common birds usually found in scattered pairs in a wide variety of habitats.