ABSTRACT
Among environmental factors affecting life - history traits of birds
breeding in nest boxes, an influence of microbial communities is
relatively poorly understood. In this study, nest boxes used for
breeding by great tit (Parus major ) and blue tit (Cyanistes
caeruleus ) were sampled before the start of the breeding season to
assess the bacterial loads of the nest box. Samples from the entrance
hole and the interior of the nest box were taken at two different study
sites: an urban parkland and a natural forest. Nest boxes were sampled
to check if their bacterial loads differed between habitats. The second
objective of this study was to check whether the occupancy of the nest
boxes during the previous season would influence the bacterial load of
the nest box. To verify this prediction, two categories of nest boxes
were sampled at both study sites: nest boxes occupied by any of the two
tit species in the previous season for breeding and nest boxes that had
remained empty that year. The bacterial load of the nest box was
significantly higher in the forest study area in both the occupied and
unoccupied nest boxes. The nest boxes used for breeding in the previous
season had significantly higher bacterial loads, but only in the forest
area. Our results suggest that the bacterial load of the nest box can
vary between habitats and may be positively related to the presence of
the nests in the previous breeding season.
Keywords: nest boxes, bacterial load, great tit, blue tit