i remember that there were only owls heard in the dead of night while i lived
at a fishing village of Murrells Inlet SC for a dozen years,
when i relocated to the city of Phoenix AZ, the din of bird sounds became natural to me
returning to myrtle beach in SC, living on old airforce base & then on a golfcourse and
finally in a established residential area old as the early 1960s...
A rare bird was actively in song at nights in 1998, but by Y2K it was normal to hear
songs at nights, now/since about 2005 the bird songs are incessant especially in the spring
when the chicks hatch... here in the cold, rainy weather of winter, the songs are once again rarer
and its not because i;m inside more or have the windows & doors shut...
i believe the birds are busy holed up out of the inclimate weather.... but thats just my experience
as a birder afficinado
On the other hand, i might guess that birds have been receptive to low fequency rumblings as the
crust is undergoing increased new stresses since the early 1990s...when the Earth interior had
been slowing down its fluid spin...thus affecting the layer of mantle upon which the Earths' crust
floats on top of... the less mixed liquid rock is creating new hot-spots on new areas of the tectonic plates
which in turn causes new fractures in the strata that the birds (& other animals) sense/hear
If the land was relatively quiet and asleep as it has been prior to the 1990s, except for active fault
areas or near magma chambers under volcanos or for that matter Yellowstone,
(i bet the rangers & park service at Yellowstone have long ago experienced the bird populations
being on a shift basis all 24hrs a day... even without the city lights & traffic noise.)
edit on 17-1-2011 by St Udio because: (no reason
given)