UKC

Free entry to their reserves for 16 - 24 year olds, and their reasoning is spot on:

“At the moment we know we need to do more to engage and connect with 16-24 year olds. Young people are less likely to visit our nature reserves than other age groups and we know that cost is one of the main barriers.  By removing entry charges, we hope more young people will come to explore these wonderfully wild places and connect with the great outdoors in new ways.”

And I know that for Leighton Moss RSPB reserve, they knock 50% of your entrance fee (normally £9) if you arrive by bus/train/bike.  Another brilliant move.  

Meanwhile, when I took my 22 year old son to Martin Mere (Wetlands Trust) last week  it cost me £16.  Extortionate. 

I was right with you until the very final word.

Family membership is reasonable as well. There's only the two of us, but we visit once a month (largely for walking with a bit of peering at birds).

Must admit I didn't know that the RSPB charged for access to its reserves (rather than visitor centres). Is this a difference between Scotland & England & Wales ? My local RSPB reserves when I last lived in Scotland were Abernethy (which includes much of the Loch Avon basin) & the Insh Marshes & both were open to all although you had to pay for entry to the Osprey Centre at Loch Garten. Was the same last time I visited a couple of years ago.

But a good initiative to encourage young visitors

Entry fees vary. I guess where they have a visitor centre, hides etc etc they charge. The rspb reserves nearest me are free, but basically you walk on public footpaths looking into the land they have purchased.  

You can walk freely through RSPB Leighton Moss (and enter the public hide) along a public bridleway. You can also go into the nearby visitor centre and café for free. The other hides are on RSPB land which isn't covered by the CRoW act so members only. I suppose the much more open access laws in Scotland wouldn't permit a member only chunk of countryside.

I think all bar one are free now in Scotland; Loch Garten being one where charges apply still afaik. Some others used to charge until recently, but changed to free at some point in the last few years. A few charge for the car park for non members, but are free to enter otherwise.

Loch Leven was one for example where they used to charge entry but not car park. Made sense to change to free entry recently as you could access the reserve from other directions anyway if you walked or biked, or went before or after opening times. The car park is not expensive anyway (£3 day rate for non members) and it does permit anyone to park and say go walking/biking instead and still get use of cafe/shop when it is open, and toilets as well which are available 24/7. They also allow overnight parking, including camper vans for something like £5 which has to be a bargain for a overnight stopover with toilets.

Overall, the RSPB has some 170+ reserves in UK, but according to what they say they only charge at 21of them.