Presumably you didn't write it by hand as you'd use duckgo.com then I suspect. So, why not provide the terminal page URL instead of this forwarding page?
I set it as my default search engine in Chrome, and it first I kept going to Google manually for specific searches where duckduckgo isn't good enough, yet. But after I learned that "!g <search>" would do that for me with less hassle, I grew much happier with duckduckgo.
I was aware of the bang syntax - just if you manually wrote out the URL I expected you to use "dukgo.com/?q=!wa ..-.." or whatever rather than a long handed version.
Personally I use "wa" as a search keyword and then enter "wa ..-.." into my address bar.