A most perfect garden path headline. It’s interesting that this one depends on our automatic processing of headlines with their own syntax.
The classic garden path sentence, “The horse raced past the barn fell”, is a full sentence and not a headline, and in that one the garden path is created by our preference for initially interpreting “raced” as a main verb; only when we hit “fell” do we backtrack and reprocess “raced” as a passive participle and “raced past the barn” as a modifier of “horse”.
In the sea turtles headline (Yahoo Science News, July 16, 2010), “rescued” is a passive participle in both the initial and final parsings – we don’t mistakenly interpret “rescued” as a main verb in the past tense, because we are not inclined to think that the sea turtles rescued anything, and the “from” phrase further makes it clear that the turtles were the rescued ones, not the rescuers. So what’s the garden path about?
It comes about because among other standard headline conventions, “are rescued” or “were rescued” will always be written just as “rescued”. So really the temporary ambiguity and its resolution is almost identical to that in the “horse raced” example: We initially take “[are] rescued” to be the main verb, and only when we hit “released” do we realize that the main verb must be “[are] released”, and that “rescued” is just a participle (with no understood “are”), and “rescued from [the] Gulf spill” is a modifier of “sea turtles”.
Every language will have its own constructions that help to set up garden path sentences, and probably every language used in newspapers will have its own conventions for headline syntax (and different newspapers or online news services may have their own as well – I recall some recent Language Log discussion of Reuters’ use of “says” + finite verb (“says finds” etc.), but I can’t find the entry). I would hazard a guess that English provides more sources for garden paths than, say, Russian, because Russian has such rich morphology, hence fewer grammatically ambiguous lexical forms.