© 1968 by Institute of Chartered Foresters
The Dean Nestbox Study, 1942–1964
Regular observations began in 1948 in the Forest of Dean, Gloucestershire, England, on an area of 60 acres carrying eventually c. 275 nestboxes. The area, planted to Quercus robur in 1814, has the appearance of a Quercetum petraeae. Three-quarters, not grazed since 1947, has a varied shrub layer and a field layer distinguished by brambles and bracken; the grazed area has a bracken/bluebell field layer. Invertebrate life has been studied mainly in relation to the food of titmice Parus spp. The breeding bird community includes most of the species of British oak woodland. The main occupants of the nestboxes are two summer visitors, the Pied Flycatcher Ficedula hypoleuca and Redstart Phoenicurus phoenicurus, and two residents, the Great and Blue Tits, Parus major and P. caeruleus. There is some evidence of interspecific competition for nestboxes, but blocking of the entrances to exclude the residents and favour the summer visitors gave inconclusive results. The populations of both seem to fluctuate independently (Fig. 2). All the species were able to tolerate each other as neighbours. The effect of hard weather on the residents is demonstrated graphically, but is only one factor in a complex situation. No evidence has emerged from the study that small insectivorous birds can contain a major larval infestation.