  We generalize theories of graph, matroid, and ribbon-graph activities to
delta-matroids. As a result, we obtain an activities based feasible-set
expansion for a transition polynomial of delta-matroids defined by Brijder and
Hoogeboom. This result yields feasible-set expansions for the two-variable
Bollob\'{a}s-Riordan and interlace polynomials of a delta-matroid. In the
former case, the expansion obtained directly generalizes the activities
expansions of the Tutte polynomial of graphs and matroids.
