Birds of castle?
I thought it was going to be a BOC 
Same
Definitely read the reviews. All the low reviews point out that humming birds won’t use them. All the positive reviews say they’re cute.
Bulls on Cows
I agree with you. We bought them last time around. Hummingbirds are not using them. They do look cute though. Maybe wasps or a tree frog might use them. We are in the middle of the southbound hummingbird migration and they are more interested in the feeders than these things.
Maybe all the negative reviews are from people who have neighbors that play a lot of Nickleback.
I came here for the BoC comments. However I also pleasantly surprised by a Nickelback dig.
They won’t use them because ad small ad hummingbirds are, these are just too small even for them. The “LOTKEY Hummingbird House” they had in a two pack earlier today at 3" diameter would have (contrary to other comments there) possibly worked, because those opened wider above the floor. The hourglass shape of these is no good in any size for any birds I have had live on our property. I’m kicking myself for not trying a pair of the Loykey brand to replace the two home made ones I have as at 15 years they are in pretty sad shape. But the Hummers that comes by here every spring seem to like them so maybe I’ll leave them alone…
Huming birds build open nests, they rarely reuse, they don’t use other birds nests, but mostly they never nest in cavities. The size isn’t the problem, it’s the wrong type.