Young Peregrines can be deceptive.  They often behave outside our range of expectation for a falcon and the whole tail to primary ratio thing can be difficult to judge when birds are posed in less than perfect postures. 

Now let me be clear, just because I find a cormorant where a Yellow-billed Loon was previously reported, or a Peregrine where others reported a Gyr doesn't mean somebody made a mistake.  The Two Bird Theory has proven itself on more than a few occasions, but finding a Mountain Bluebird in the spot where the Black-throated Blue Warbler was reported and only out of season Savannah Sparrows where the Sharp-tailed Sparrow was supposed to be do suggest mis-identification as a real possibility...

We all make mistakes.  The fate of the free world does not hang in the balance should we get the name wrong on the first try.  I once saw a bird at Brownsmead.  I took a 8 or 10 photos and dutifully reported that a Cattle Egret was hanging out in the pasture behind the Grange.
When the pictures came back from the developer, I wrote Cattle Egret on the slides and filed them away.  Three weeks later Harry Nehls found a bird in the same place and identified it as a Little Blue Heron.  When I re-examined my photos, guess what?

The bird hung around for some time and everyone who wanted to got much better photos.  But they should have been able start 3-weeks earlier...