The greatest conservation fundraising program in North America is now on sale- the federal duck stamp..Taking effect on July 1st its a handy free admission to National Wildlife preserves. Started in 1936 I think, it has raised 100 s of millions of dollars for habitats and conservation causes. Available thru the us postal service website if a wildlife refuge isn't nearby.
https://www.fws.gov/birds/get-involved/duck-stamp.php
https://store.usps.com/store/browse/emailAFriend.jsp?productId=S_335401&categoryId=duck-stamps
While on the subject of bird stamps, the Post office came out with new bird stamps on august 4 winter birds..Songbirds in Snow
https://store.usps.com/store/browse/emailAFriend.jsp?productId=S_681104&categoryId=buy-stamps
https://store.usps.com/store/browse
This years stamp depicts Trumpeter Swans. /