The common kestrel is evaluated as Least Concern at global level. However, at the European level, the species is considered of conservation concern due to a continuous moderate decline since the 1980s due to agriculture intensification, landscape simplification, pesticide use and loss of nesting sites. Moreover, the conservation status of some subspecies of common kestrel appears problematic. This chapter discusses the conservation status of kestrel species and subspecies, and the main top-down and bottom-up factors that affect the viability and stability of their populations. It also points out the strong limitations of our knowledge about the density-dependent and independent processes that regulate the demography and dynamics of kestrel populations. Important conservation-related topics, such as urbanisation, pesticides, or use of artificial nest boxes, have been discussed in detail in prior chapters.

The number of birds breeding in a given area (breeding density) is affected by several abiotic and biotic factors. Availability of suitable nesting sites plays a major role in determining the size of the local breeding population of birds, particularly in those species, like the common kestrel, that do not build their own nests. Kestrels do actually use old nests of corvids or holes in buildings to breed. By provisioning kestrels with artificial nest boxes, it is possible to increase the number of breeding individuals and, possibly, the population size. However, a number of factors need careful consideration to evaluate a priori the characteristics of nest boxes and locations to install them and to assess a posteriori the effects of the nest box provisioning on the reproductive ecology and population dynamics of kestrels.