We have hummingbirds around almost all year so we always keep at least one feeder filled for them.
The one we have now (from WalMart) did not come with a perch so they had to hover in the air while feeding.
We have had feeders in the past that had perches and so we know that they will stay far longer at those because they can rest.
The top of the base on this feeder removes for cleaning so it was easy to design a perch that fits between the top and the base cup.
This does not cause any leaks or other problems and is very thin at the mating line so it doesn't affect the assembly of the base parts.

It was designed for a 116mm (4.57") diameter top cover.
You will need to scale it in your slicer for your cover if it is different.

Since making and installing this perch we have had a number of occasions where all three feeder positions were occupied at the same time.
This basically never happened when they all had to hover, so clearly they like it and are more comfortable hanging out for a while. :-)