  We analyse several implications of lensing by the regular component of the
galactic magnetic field upon the observed properties of ultra high energy
cosmic rays. Magnetic fields deflect cosmic ray trajectories, causing flux
(de)magnification, formation of multiple images of a single source, and time
delays. We derive the energy dependence of these effects near the caustics at
which the flux amplification of a point source diverges. We show that the large
magnification of images around caustics leads to an amplification bias, which
can make them dominate the flux in some energy ranges. We argue that clustering
in the arrival directions of UHECRs of comparable energy may be due to magnetic
lensing around caustics. We show that magnetic lensing can also significantly
alter the observed composition of cosmic rays at the highest energies. We also
show that the time delay between events from a single image may monotonically
decrease with decreasing energy in the neighborhood of a caustic, opposite to
its behaviour in normal regions.
