The great titmice (Parus major L.) feeding social and solitary bees (Apoidea). Investigations of bumblebee population structure and dynamics prove that great titmice can periodically feed on Apoidea to a considerable degree. In 1972 and 1973, in each case during the spring, beside 70 solitary bees 130 Bombus- and Psithyrus-♀♀ picked apart by great titmice were collected in the Botanical Garden of Kiel. — The most endangered were the Bombus hypnorum and the Andrena fulva.
The death rate attributable to this bird-feed has turned out to be dependent on the course of temperature and sunlight. This was evident not only over longer time periods, but also over the course of a day. Apoidea were especially jeopardized at temperatures ranging from 13°–21° C. A sudden temperature rise after a prolonged period of inclement weather revealed itself as particularly unfavourable. During the spring Apoidea were consumed in two distinctly demarcated time periods, which is explained by the two separate broods of titmice.
The great titmice captured bumblebees and other wild bees almost exclusively on blossoms. The preparation of their food happened in the following manner: detachment of the stinger (along with frequent severance of the distal segments), ingestion of the abdomen - segmentation of the thorax and the removal of its contents. There are indications that the affixation of titmice nest-boxes can affect bee populations together with their pollination intensity, i.e. in fruit-growing areas.