Geography Reference
In-Depth Information
In subirdia humans augment the actions of woodpeckers by of ering nest
boxes that facilitate secondary cavity nesters. Providing nest boxes is a com-
mon practice, especially in Europe. Barbara Clucas and Sonja Kübler, freshly
minted Ph.D.s from the United States and Germany, respectively, studied
this strand in the urban ecological web in Berlin, Germany, and Seattle. Team-
ing up, they traded binoculars for interview scripts and started knocking on
doors. After nearly six hundred discussions, some with more than interesting
residents, Barbara and Sonja discovered that one in three Berliners and one in
i ve Seattleites had a birdhouse. Nest boxes were most common in suburban
and rural neighborhoods and less frequent in the core of the cities. Provisioning
birds with nest boxes forged another link between residents and the birds
that shared their ecological web. Neighborhoods with strong connections—
where people frequently said they provided boxes—had substantially greater
numbers and a greater variety of secondary cavity nesters than did neighbor-
hoods with weak connections.
In the heart of the city nest boxes and the inadvertent cavities provided in
our built structures support native and nonnative species. Starlings and house
sparrows are frequent benei ciaries of these cavities—both in their native Eu-
rope and elsewhere, including the more urban parts of Seattle. In suburbs,
nest boxes are readily and successfully used by native species. Chickadees
and Bewick's wrens l ock to them. The ability of violet-green swallows to
dominate subdivisions is in large part due to their use of human-made nest
cavities in boxes, soi ts, and streetlamps.
The use of nest boxes and built structures by nonnative species such as
starlings could preclude nesting by native species. Starlings aggressively de-
fend their nest cavities from a wide range of species. Sometimes they even
