Changes in external circumstances (phenology, weather, food balance) have a powerful influence on the performance of the A.m.mellifera bees. Brown bees are calmer in spring and fall, but they become more aggressive during bad weather in comparison to other bees. They have a wide behavioral ability to react to environmental changes. As a result, you might be very surprised to see very different kinds of bee colonies in different years and places with the same origin of bees.
Some differentiating features of Nordic brown bees in comparison to Italian, Crainiolan, and Buckfast bees include: