As one might expect, I spend quite a bit of time watching animals, trying to work out what they're doing, why they're doing it, and — in the case of mugger ducks — how I can get them to stop doing it. Much of this happens at work, but I also watch animals in a non-professional setting, as I have for most of my life. Sometimes I can work out what is going on — at other times, I can only wrinkle my forehead in perplexity and think, "What the flippin' Nora is going on there, then?" This is about one of those occasions.
There are several resident cats near our flat, and — being unable to keep pets ourselves because of the terms of our rental contract — we get vicarious pet-owning enjoyment from watching them (without having to clean out litter trays!) One little cat (we call him Scaredy Cat for obvious reasons) has developed a very odd habit. Approximately every 20 minutes (while we are watching him in the evenings and at weekends, anyway) he trots over to a particular section of fence bordering the car park, sits about 10 cm away from it, looks up and stares. And stares. I can tell you that this fence is premium feline entertainment: '24' and 'The Matrix' all rolled into one. He just can't tear himself away. If cats could make popcorn, he'd be munching away on a big bucket of the stuff. At the weekend, someone parked their car right in front of his fence section. He sat right by the car, glaring at the driver who was chatting to friends, until the inconsiderate human moved the car, and Scaredy hurried over to take up his position.
The most likely explanation — I suppose — is that he's watching birds nesting in the bush growing over the fence, or insects flying around it, but he never tries to jump up. He just stares.