Pretty sure if they are that close they can smell them... But it does help to keep small nooks and crannies closed up, for ducklings, etc. And the sight barrier cleans up the place... I can mow and weed eat right next to mine and it stys looking pretty good most of the time. Just the grass in my pen, I need something to keep it down! I had to get my mower in there the other day and mow it down! Looks like I might be getting some wigeon to eat the grass down this fall. What other wild species will eat it down?