Hazel dormice are the only native rodent to the UK with a distinctive furry tail, and while they can live in many habitats, they favour woodlands and hedgerows.
However, the dormouse population has declined by 70% nationally since 2000, and a 2023 report found the species was extinct in 20 English counties.
Trained and licenced surveyors are carrying out studies at monitoring sites in Hampshire.
Ms Hadler said the combination of a warm summer and “sensational” autumn food supplies have boosted breeding and allowed second broods to be born.
Dormice normally have a single litter of four babies on average in a breeding season.
So far, one survey at Harewood Common in Andover and another privately-owned woodland counted 47 dormice at all life stages. One nest containing eight babies was found.