The Inca dove first arrived as a native of Mexico and has slowly expanded Northward into Kansas and Arkansas.
Examples of these include the Helmeted Guineafowl (introduced) and the Hadeda Ibis (natural expansion).
Exotic species, such as the European starling which were introduced by Eugene Schieffelin in 1890 in New York City and then expanded to California by 1955, often do very well in new habitats.
The lack of predators and new niche offer perfect conditions for the introduced species to flourish.
The European starling is an early breeder and out competes other native cavity nesters for nesting sites.
In the 1970s the logging of old-growth forests accelerated, and the numbers of the northern spotted owl began to decline.
The northern owl is adapted to best survive in old growth forest and relies mainly on the flying squirrel as a food resource.
The behavior of the brown-headed cowbird causes range expansion at the expense of other birds such as warblers, sparrows, and vireos.
Range expansions are important because they often signal changing habitats, whether the reason can be explained by natural causes or more often human aided causes.