I identified the Blyth's very quickly and confidently , having more than a suspicion when I heard the first call and then having the opportunity to study the size and structure at close quarters albeit with only flight views. Time was always going to be limited so I concentrated at getting the best views I could when it was overhead and then after failing to get my scope on it as it flew further away trying to compare it with any surrounding birds in flight.
To me the call of a Blyth's Pipit is very distinctive and is clearly different to a Richard's ( or Tawny ) when heard clearly. It almost sounded like it had a cold with its short sneezy call , which is rather excitable and ascending in tone in comparison to Richard's in particular.
Richards Pipit's call sounds 'longer' more schreepy and to my ear sounds less exciteable and 'downslurs' in tone.
Tawny Pipit sounds similar but the ones I have heard again sound more shreepy ( almost House Sparrow like) and seem to have a double note quality.
As for the structure and flight silhouette of the bird for me it is surprisingly distinctive once learnt. I remember very clearly the ' ulrika moment ' I had when seeing a Blyth's Pipit in 2008 at Porthgwarra with Stan Christophers. For 3 days we had been hearing this odd pipit that we suspected was a Blyth's Pipit. Finally on the final morning of our trip we got our first views , I couldn't believe how much smaller it looked! And particularly the short tail projection was so different to a Richard's ( seen in the same morning). Indeed the same could be said of the wintering Blyth's Pipit a couple of years previously (2005 I think) at Treeve Common, you had to look hard to pick it out if it was in amongst the Meadow Pipits.
Today's bird was no different, reminding me more of a Tree Pipit in size with a stocky, rather chunky appearance which in no way looked like the sleek long tailed Richard's or Tawny Pipit. Again the short tail projection ( noticeable when overhead most obviously) was very clear. Colour wise I didn't pick up much accept it looked quite contrasty probably owing to the very pale underparts and darker upperparts.
In conclusion I identified the Blyth's Pipit in a rather holistic approach based on structure and flight calls from my previous experience of them. I also relied heavily on my thorough experience of Richard's Pipit ( found over 30 in Cornwall) and Tawny Pipit ( found 3 in Cornwall, seen 100's in Spain and Cyprus). For Pete it was a lifer and he enjoyed soaking in the moment, but he also helped me greatly by keeping tabs on the bird as it flew about. I understand it will be difficult to get through BBRC without on the deck views so fingers crossed it gets seen again, with all the eastern stuff about in West Cornwall god knows what else is about so it's worth getting in the field again tomorrow anyway! We are heading to Lands End....