Birding know how
CP exhibits a good knowledge of ornithological matters. His strengths may lay in those areas away from pure identification. WEO is a hoary old time birder through and through, scarred from various campaigns on many distant northern islands and sojourns on Scilly. His find rate will be higher. But if you ask them to write an essay on 'The Life of a Spotted Flycatcher' then CP may shade it. If you ask them both to sift through a fall of migrants on Blakeney Point then WEO should burn CP up. Hard to call but...
All-round natural history knowledge
WEO is a bit of a one-trick pony here. It's birds, birds, birds all the way. CP can probably outdo WEO on an all-taxa list, and know most of what he was looking at without using 'other experts' for confirmation.
CP may have youth on his side, and look fairly athletic, but WEO has extra weight and does come over as someone that can blow a fuse. When driven to anger I reckon WEO would be a flurry of fists and boots that CP could not respond to.
Hard one to call this. It's easy to assume that CP might be a bit lightweight, but I reckon his alcohol tolerance would be better than WEO's. The latter may well fall asleep after a couple of pints. If it was the last man standing who wins, then the point goes to youth.
Deciding category. Kate Humble has the casting vote on this one. A source close to the programme has said: "Bill was never interested in Kate. He found her a bit annoying and girlish. There again, Kate wasn't interested in short dumpy men with beards. Chris pays Kate Humble far more attention, which she likes. He's younger and better looking, although Kate thinks that his haircut is a bit wimpish and too young for him. Truth is, Chris is far more interested in the spider crawling through her poodle-like hair than in her. However, she wouldn't climb over him in a bed to get to Bill'.
So, there we have it, Chris Packham is the undisputed better presenter. However, if he ever comes up against that muscle-bound Steve who appeared on the Bhutan tiger documentaries, he'd get his arse well and truly spanked.