female house sparrow sitting on an
agave stalk near Tempe City Hall.
house sparrows were introduced to
New York in 1850 and spread to
California by 1910, they are now
found all across the U.S., Canada,
and Mexico. in the nearly 100 years
since their expansion, they have
developed some geographic
variation due to varying environmental
conditions across their range. northern
populations tend to be larger and
our southwestern birds are a bit paler
than those in the eastern and Pacific parts
of the U.S.