The first thing to realize is that the Sponsored Links search is unrelated to the keywords chosen by the advertiser to display the ad. Instead, the results shown are the ads that include the query words in the ad text. That's why you'll see only one or two ads at google.com/search?q=raccoon+squirrel (because it's not a great keyword to advertise for) but lots of them at google.com/sponsoredlinks?q=raccoon+squirrel (all of the ads shown contain those two words).
So if the Sponsored Links search is unrelated to the keywords and shows just the ads that have the query words, that's why it uses the default destination URL for the ad rather than the specific ones for the keywords.
There's some information on Sponsored Links search at [adwords.google.com...] but it's not really fully explained.
Just one other thing if I have you confused... Sponsored Links search used to be based on keywords, but its functionality changed around June 2008. So up until that time, it would have behaved the way that you were expecting above; but after the change, the results shown have changed significantly.