Walking in the morning,
(Southbound)
I saw a tall tree scoot
under a hovering bird,
which, not powered by the mass
of the tree's unfair rootball,
was unable to keep up.
Returning, (Northbound)
I watched the little bird,
straining valiantly back East
trying vainly to keep pace,
and, for a few moments,
winning a lap!  (Oh, brave!)
But massless birds with no
orbital or angular momentum,
(to speak of)
must sustain motivated flight
or give up; she dropped
and cheated, (all she could do)
bumming a lift from the Tree.

I cheated both by moving only
South or North.
I am the Laughing Mammal.