Just come across online bid identifier – for UK, mainly garden birds – on RSPB website, at Bird Identifier
Simple stuff – get multiple choice questions for categories Size, Feathers, Beak and Other.
Hardly the thing I expect hard core birders n twitchers to use (tho maybe a kid lister or two might find it handy…) .
But maybe here’s a glimpse of field guides of the future – perhaps for a handheld device, with impressive store of info and ability to help: might be a boon at times in new places, especially with tough genera. [Not sure if such things available already; but over time, could become very nifty. Some day, binoculars that identify birds?]