An old wives' tale. Birds have no sense of smell (as we know it), and
are not repelled by our odors. More likely taught to little children
to keep them from going near birds' nests - a reliable (though small)
potential source of food... If the bird is obviously too small to
survive out of nest (feathers still pins), and you know the nest, by
all means put it back! It could have fallen out, been pushed out by a
sibling, or blown out in a high wind. If, however, it is fully
feathered, step back and see if a parent comes to feed it. Patience
is required to allow for the adults to find food and come to the aid
of their "child". It is not necessary to just watch it die, if it
could survive in a nest. If it does not survive in the nest
(abandoned by adults - sometimes one eaten by a hawk or other
predator), then at least you gave it a better chance than freezing to
death on the ground.
Jim Greaves, Thompson Falls MT