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

I'm new to house plants, but i've killed one birds nest fern before and the second is thriving (this is how we get to be good at caring for a particular kind of plant it seems you have to kill one and learn from your mistakes). What i've found is that it's easiest to water from UNDER the plant. What i mean is when the surface of the soil in the pot is dry (check it every other day folks you don't want it to get starved). Take it and set it in a shallow bowl of water mixed with the right amounts of liquid miracle grow houseplant food. Let it soak maybe 15-30minutes or until either all the water is absorbed or the surface of the soil is moist. If the soil is dry on the top and the water is all absorbed add more and check every so often. when the soil is thoroughly moist, remove the plant and drain for a few minutes (i stick it in the kitchen sink) and then return it to it's normal home. My 4 inch plastic pots sit inside glazed ceramic containers to dress them up and keep moisture from getting on the windowsill. Watering from underneath avoids crown rot (which i understand to be a problem common to this plant), and it assures even moisture in the soil, i've noted it's hard to get the soil fully watered when watering from 'overhead' esp since i have a 4inch pot for my birdsnest fern. Also i noticed in TOO HIGH lighting conditions the leaves get really really pale almost white even after just one day. When not watered enough the leaves get really dry and start getting brown spots at the edges. With crown rot i started loosing leaves rapidly and no new leaves would spring up out of the crown. I can tell my plant is healthy the way i've been caring for it now (after a few months after bringing it home from the nursery) the fronds have gotten darker (they started almost yellow and are now darker)and i'm getting new buds poking through the crown. My birdsnest fern is in a west facing window with a 6 foot porch overhang. It gets gentle light until the end of the day just before the sun sinks over the horizon. It doesn't seem to prefer bright light, nice 'understory' kind of filtered light seems to suit it well. (like what you'd get under a tree) I've started watering all my houseplants from underneath (with exception of my orchid which gets misted). The african violets and my birdsnest ferns love being watered this way from my experience. I've only had these about 6 months but for now it seems everything's going quite well.

I haven't seen that problem before but was wondering whether it might be from something in tap water. Rainwater is best. They're an epiphyte (and lithophyte) from rainforests, mostly growing on trees with no soil and roots exposed to the air.

G'day, my Bird's nest fern has done this as well. Doing some research i read some place that it could be using hard water for a long time. the town i live in is quite renowned for having very hard water so perhaps it is true. I am doing to try watering only with the filtered water. fingers crossed :-)