Tree Swallow Range Expansion 107 



Nesting was recorded in 1988 and 1989 and will probably continue 

 in the future. In 1988 and 1989 a pair nested in a purple martin 

 (Progne subis) gourd in Cowee Valley, Macon County, and in 1990 

 a pair nested in a bluebird box near Piney Creek, Alleghany County 

 (Chat 55:64-65). The Piedmont birds were seen nesting in woodpecker 

 cavities in trees killed during flooding to create Jordan Lake in 

 Chatham County in 1988. A nesting pair was found in Vance County 

 in 1990. To date these are the only confirmed nesting birds in the 

 Piedmont. In the Coastal Plain, tree swallows were found nesting in 

 eight locations in Currituck County (1989-90), and were seen during 

 the nesting season in Pamlico County (1988) and along the lower 

 Cape Fear River in Brunswick County (1990). In the Coastal Plain 

 pairs of tree swallows used bluebird boxes and natural cavities in 

 trees killed by impoundment and where natural flooding occurred 

 along rivers and in salt marshes. 



DISCUSSION 



Although present day land-use patterns provide fields and other 

 open areas suitable for swallow foraging, this alone does not account 

 for the current, explosive range expansion because land clearing was 

 widespread in the Southeast by the early 1800s. Nest sites are critical, 

 and the same land-clearing patterns that provide open areas can also 

 eliminate snags and other potential cavity-nest sites. The elimination 

 of beavers from most of the Southeast at the turn of the century 

 eliminated the potential for natural snags in areas impounded by beavers. 

 Dead trees resulting from flooding in tidewater areas and adjacent 

 salt marshes seem to have provided a natural dispersal route in coastal 

 areas. Therefore it is interesting, and not easy to explain, that, despite 

 the availability of natural habitat, tree swallows have only recently 

 (since 1913 in Virginia; late 1980s in North Carolina) expanded in 

 , tidewater areas. It is to be expected that coastal tree swallows will 

 also follow river systems inland and make use of dead trees in im- 

 poundments and beaver ponds in the Coastal Plain. 



Phenology — Tree swallows are relatively early to late spring and 

 early to late fall migrants, making it difficult to distinguish resident 

 breeding birds from migrants. In Currituck County, North Carolina, in 

 June 1990 I observed resident birds using cavities before, during, and 

 after a fairly extensive northern migration of large numbers of transients. 

 Nicholson and Pitts (1982) noted tree swallows at Reelfoot Lake, 

 Tennessee, by mid-March, and territorial birds by late April when 

 northbound migrants were still present. Southward migration in the 

 southeastern United States begins in early July (Nicholson and Pitts 



