Following a treaty between the US and Great Britain to protect migratory birds, Congress enacted the Migratory Bird Treaty Act (MBTA), 16 U.S.C. § 703-711, making it illegal to “pursue, hunt, take, capture, kill, attempt to take, capture or kill, possess, offer for sale, sell, offer to purchase, purchase, deliver for shipment, ship, cause to be shipped, deliver for transportation, transport, cause to be transported, carry, or cause to be carried by any means whatever, receive for shipment, transportation or carriage, or export, at any time, or in any manner, any migratory bird, . . . or any part, nest, or egg of any such bird” unless permitted by regulation. (16 U.S.C. 703)