The Air Marine Division of CBP Customs is now operating out of Selfridge ARB in Michigan. This makes a total of 5 AMD air bases along the northern US border. The others are Bellingham, WA, Great Falls, MT, Grand Forks, ND and Plattsburg, NY.
http://www.detnews.com/apps/pbcs.dll/article?AID=/20080805/METRO03/808050353/1412/METRO03
http://www.cbp.gov:80/xp/cgov/newsroom/news_releases/08042008_5.xml
Listeners should keep an ear out for activity on the known UHF air band frequencies set aside for use by the AMD, http://mt-fedfiles.blogspot.com/2006/07/customs-and-border-protection-amid.html.