actually a trail can have a HUGE impact on a flying mammal, ever hear of the edge effect? A basic postulate of island biogeography.
$5,000 is a rather reasonable bid, but you have to question what kind of 'science' this engineering firm could produce. The best option is to find a graduate student to do the research as part of their thesis. Cheap and reliable. Indiana State already does a ton of work on the Indiana Bat.
gf
I've heard of it when speaking of migration patterns of other ground dwelling species, but never on something that flies.