The comparative survey on the building materials and the nest biometry of P. nigerrimus and P. cucullatus in the monospecific colonies in Kisangani had for main objective the assessment of the knowledge of buildingmaterials of these two species in relation to their specificity. In total, 90 nests were equitably picked in six stationsfor the two species (i.e. 45 for P. nigerrimus and 45 for P. cucullatus).
Different measures were used in this survey, namelyt: the weight of nests (in gram), the height (in centimeter) (hl and h2) and the diameter of portal of entry (in centimeter) (dl and d2) were taken as well as the weights of each building material.
The results show that the inflorescences of Poaceae (Bambusa vulgaris, Sporobolus pyramidalis, Maximum panicum, Penisetum purpureum and Eragrostis tenella) and leaves of the host trees (Mangifera indica, Acacia kirkii, Dacryoides edulis and Elaeis guineensis) are the main nest building materials. These materials are exploited in different proportions and also play specific roles in the nests.Out of 14 identified plant species, only five species were found in the nests of P. nigerrimus (Elaeis guineensis, Bambusa vulgaris, Dacryoides edulis, Persea americana and Cassia siamea); four in the nests of P. cucullatus (Elaeis guineensis, Bambusa vulgaris, Mangifera indica and Raffia gilletii). The average weight of the nests of P. nigenimus is of 53.02 g; while the one of P. cucullatus is of 67 g.