On Saturday at Font Hill Wetland Park (Howard Co) I was watching a 
goldfinch in a small ash tree. The finch was clinging upside-down to a 
green leaf that hadn't fallen from the tree yet, and was eating berries. 
A White-throated Sparrow flew in (apparently without noticing the 
goldfinch) and tried to land a couple of inches away. The finch then 
hissed at the sparrow, and the sparrow jumped up and perched a few feet 
away!

I had no idea finches were even capable of hissing, let alone that they 
occasionally do it. The hiss sounded just like the hissing sound various 
mammals make when they object to the presence of an intruder.

-- 
June Tveekrem
Columbia, Maryland
tweekiebird|AT|southernspreadwing.com