Geography Reference
In-Depth Information
doves. That is when Eurasian collared doves became increasingly common.
White-winged doves dominate collared doves and have remained abundant
in New Mexican subdivisions. But Inca doves have been unable to do so, de-
clining in number shortly after the Eurasian invasion and disappearing from
some areas i ve short years later.
In Florida a similar story is unfolding, though scientists are quick to point
out a positive association between their native doves and the invaders. All
doves—mourning, ground, white-winged, and collared—co-occur in residen-
tial areas where food is abundant—Florida's version of subirdia. But during
the i rst decade of the twenty-i rst century, the numbers of Eurasian and
white-winged doves, both invaders in Florida as in New Mexico, continued to
increase while native mourning and ground doves (a small species closely re-
lated to the Inca dove) declined. That the native doves remain in Florida's
suburbs may have everything to do with climate.
The high elevation of New Mexico imparts a strong seasonality to its cli-
mate. Snow and freezing temperatures are common in Socorro during the
winter. These challenges to ground-feeding birds such as doves are rare in sub-
tropical Florida. During these ecological crunches competition may be severe.
Perhaps this is why New Mexican white-wings were able to oust mourning
doves, and Inca doves have been excluded from the northern portions of their
range. Although this is a reasonable scenario, we cannot be sure whether, or
how important, competition has been in restructuring the dove community of
Socorro. It is possible, for example, that cold winters alone doomed the Inca
dove. In warmer cities of southern Arizona, Inca dove numbers are actually
increasing. As temperatures drop, these small animals stay warm by huddling—
actually forming pyramids that keep the central birds especially warm. Every
i ve minutes or so the birds reshul e; inner birds move out and outer birds
move in so that the group can survive. (That's something I'd like to see!) Unfor-
tunately, at even moderately low temperatures (less than twenty-one degrees
Fahrenheit) Inca doves die. The true interactive ef ects of climate and invasive
