I've done some research, and it's worth noting that pretty much everything called Asplenium nidus is actually Asplenium australasicum. So I should really say it's probably A. australasicum. The difference is based on the sori. They appear as brown, fuzzy, diagonal lines under the fronds. (Your plant may not have sori.) According to the source below, the sori in A. australasicum are half or more the distance between midrib and margin. So basically, I'm thinking it's Asplenium australasicum rather than A. nidus var. plicatum. I've seen larger plants get wavy over time. The source below says the plicatum should be more convoluted. Here is a link that might be useful: Bird's Nest Fern

Carpenter ants will not harm a live, healthy tree. They indicate there is something wrong with the tree- there was rot or something they were working on. My dad grew up as a lumber jack and they knew to look for trees that carpenter ants had/were working on; that meant they had punky spots and weren't good for logging. We have big nests of them in our back yard and have never had issues with them. They don't come in the house (though they did in the house i grew up in, in PA). The ones in our back yard make nests probably close to 4' wide, but they don't seem particularly aggressive, though i wouldn't stand in the middle of one, either. We just work around them and they move around some through the years. Incidentally, though we have fire ants up front where i've not seen the carpenters much or at all, we still don't have the fire ants in back where all the carpenters are. I'll take the carpenters any day of the week.

Ok,The Oriole makes a nest high in the tree,and the Bushtit is more often lower down, the diference is that the BT nest is longer than the Orioles, because it holds more babies.

Tammy, I am so glad that BN and Lisa could ID it.... I had no idea what type bird built that nest. I am covered up with Am. Goldfinches but have never laid eyes on a nest! Very pretty! I hope your adults return to this one.