5. CONCLUSIONS
Our study demonstrates that the observed difference in the bacterial
load of the nest box is probably related to habitat-related differences
between the two study sites. The most important factors are probably
associated with the richness of plant species and the physical
properties of the soil, with additional factors resulting from the
specificity of the two study sites. However, taking into account the
complex and yet relatively weakly understood relations between
microorganisms, their hosts, and the environment, probably other factors
play their role and we are still far from understanding this issue.
Furthermore, we should treat our results with care since we do not have
data on the richness of bacterial species at both study sites. However,
our study suggests that the bacterial load may be a potentially
important factor for the life-history traits of secondary cavity nesting
birds, since it may vary considerably between habitats. Therefore, since
studies on cavity nesting birds with the use of artificial wooden nest
boxes are widely conducted across a geographical range and a variety of
habitats, and given that bacterial load may affect host fitness
components, we consider our study perspective as a promising field for
future research.