Canon Timer remote or 3rd party?

Thanks to forum members I bought the Yongnuo 600EX RTII rather than a Canon Speedlite as a replacement for my malfunctioning 430EX. I'm now looking at interval timers for my 6D and 70D. Looking at Adorama's website there are many to choose from, too many for a novice like me. Which one do you recommend? I'd like to set up either body with my old model 100-400 L and photograph the wildlife that visit my bird feeder by taking a photo every few seconds. This will be a Christmas present so I'd like to go as cheap as possible.

Sorry, I haven't shopped for timers yet, but basically speaking: I'd go for a cheapo and read through customer reviews. I think i 've seen such on Adorama but am sure you'll find some on Amazon. More money spent is most likely to buy you durability and or programming ease. - Both don't sound crucial for your project.

The bigger issue: Why produce data junk by shooting an unoccupied feeder too? Wouldn't it be better to trigger your camera via some kind of motion detector as seen on automated outdoors lights for example?

Why not tether the camera and trigger manually?

I fished some 3rd party radio trigger for my 5D out of some bargain bin. - 3 Euro? While my watchmaker allures aren't big I suppose hacking such a trigger and attaching some kind of gears to operate it should be doable.

I use the Vello Wireless ShutterBoss (version II) with my 6D. My only complaint is the receiver eats batteries when not in use. It even arrived with a dead battery. So I remove the battery before I stow it in my camera bag. I see the version III has switched from a single CR2 to 2 AAA's. Perhaps they have taken care of the issue. Functionally it works without fail though it can be tricky to set up and use in the beginning until you become familiar with it.