Ian I know that route well going down to Amersham many times. If you want to show your son some spectacular Kite action outside the car turn off the M40 at J6 and go to Kingston Blount on the B4009 to Chinnor then follow the track up to the Ridgeway beneath the Chiltern escarpment. Or go further to Coombe Hill above Butlers Cross on the B4010 where you can see spectacular views of the Vale of Aylesbury and spy into the PM's garden at Chequers without any security at all! As well as watching Kites.
2 and half hours at 70 miles an hour...all the way to Windsor
A trip down south today involved a motorway journey from Manchester to Windsor near London and what better way of keeping a 10 year old passenger happy than involving him in a 'motorway bird list' Of course son and I shared the spoils and often avioded multiple pile-ups as I gazed up at passing raptors but infact our list of the 230 mile journey which took around 2 and a half hours was a surprising 30 species! My son also kept a tally chart of the total of each species seen (chip of the old block ) and in honour of his hard work and effort, his results are listed below:
Lapwing- 3 Magpie-8 Black-headed Gull-2 Crow-45 (plus over 100 unidentified corvids at long range) Kestrel- 5 (I remember when they were by far the commonest raptor seen from motorways, but not now ) Woodpigeon- 12 Jackdaw- 23 Buzzard- 25 (now undoubtably THE commonest raptor seen along motorways) Swift- 3 Starling- 14 Blackbird- 1 Rook- 21 Blue Tit- 4 Stock Dove- 1 Grey Heron- 1 Jay-2 Mallard- 2 Swallow- 1 (poor year for this species or what ) Mistle Thrush- 1 Sand Martin- 1 Lesser Black-backed Gull- 1 Chaffinch- 1 Great Tit- 1 (but probably about 3 more) Great Spotted Woodpecker (right in front of the car flying across the motorway, a true 'motorway mega') Goldfinch- 1 Raven- 1 (another of the true 'motorway megas' that had me veering lane to lane as I peered up at it ) Red Kite- 39 (always a pleasure to see them and staggering at just how many there can be in the air together at one time and just how close views you can get at 70 miles an hour (around the Oxford area), after pulling onto the A404 we stopped at a lay-by and watched a couple literally just over our heads for a good while. Trouble is it just made me think how much I'd love to see one in Greater Manchester )
So, just a boring list of birds seen from a car or infact a reflection of changing times for some of our native species , some of those species on there with poor numbers I can remember being common along our motorways 20 years or so ago but not so much now Either way it kept him quiet and me busy for the full journey
Of course son and I shared the spoils and often avioded multiple pile-ups as I gazed up at passing raptors but infact our list of the 230 mile journey which took around 2 and a half hours was a surprising 30 species! My son also kept a tally chart of the total of each species seen (chip of the old block 
)
)
, some of those species on there with poor numbers I can remember being common along our motorways 20 years or so ago but not so much now 
Either way it kept him quiet and me busy for the full journey