It sounds like Matt could be describing the (non-migratory?) nominate race 
tapera of Brown-chested Martin. At any rate, years ago I photographed museum 
skins of fusca and tapera, including the fusca from Monomoy. Here they are. Also 
included are few photos of the Cape May bird, showing the "pointy-headed" look 
Matt mentioned.

http://odolep.com/midatlantic%20birds/brownchested_martin/Brownchest_Martin2.h
tm

Dave Czaplak