Above One purple martin fancier has expanded on the old Indian and 
slave practice of hanging gourds for the nesting birds. Right: Located 
' near Tottenville, Staten Island, this complex reputedly houses the 
only active purple martin colony within the city limits of New York. 
The housing development for birds was set up by Howard Cleaves. 
sites in the southern and eastern 
United States. Multiroom birdhouses 
are especially conducive to coloniality 
because they contain many nesting 
sites in proximity. Single-room bird- 
houses are rarely built for martins, 
and when erected are quickly appro- 
priated by other species; as a result, 
in many martin populations, solitary 
nesting seldom seems to occur. 
Humans have provided these birds 
with many housing opportunities, and 
this has probably caused an overall 
increase in martin numbers. Yet all 
is not rosy for martins that nest co- 
lonially in birdhouses. For instance, 
spatial interference between neighbor- 
ing purple martin pairs is common, 
owing to the parents’ inability to rec- 
ognize their young. Juvenile martins, 
when within one to four days of fledg- 
