  We investigate signatures that would be produced in the spectrum and sky
distribution of UHECR by a population of the Galactic sources of high-energy
protons in the energy range around 1~EeV, i.e., around the
diffusive-to-ballistic transition. In this regime, the CR flux has to be
calculated numerically. We employ the approach that consists in backtracking
anti-protons from Earth through the Galaxy and integrating the source
emissivity along the trajectory. This approach makes evident two generic
features of the transition region: sharp increase of the total flux as the
energy decreases across the transition region, and its strong anisotropy
(appearance of a bright compact spot) all the way until the onset of the
diffusive regime. We then discuss and compare several methods to experimentally
detect or constrain these features. We find that a few percent admixture of the
Galactic protons can in principle be detected by the current UHECR experiments.
