Banded Wrens do a peculiar thing. Like normal birds they build breeding nests in which to lay eggs and raise their young, but they also build sleeping nests. Strangely, they seem to be the only birds in this dry forest that exhibit such behavior. Why do they build these nests when all of the other birds around make do with the night environment as is? That is a question that I still don’t know the answer to, but hopefully we’ll get a little closer to figuring that out. Each bird can have up to five or six sleeping nests, and we have found both males and females roosting inside. The nests are woven pockets of golden grass, usually perched precariously in delicate hanging vines and just big enough to accommodate a 20-gram bird.
My time here over the last month has been filled with finding these nests, then revisiting them at night to capture any unsuspecting wren that might be sleeping inside. We use aluminum foil to mark their locations, which serve as reflective beacons when relocating them at night. Additionally, we take copious notes including landmarks, compass bearings and distances, but even with these we sometimes fail to find a nest after nightfall. The forest takes on a whole different face at night. Moonshadows are surprisingly confusing, and obvious landmarks during the day often become nothing more than a needle in a haystack after sundown. Sounds are soft and continuous, punctuated by the occasional hoots of Pacific screech owls. 
Night hawks forage from the roads, their eyes reflecting in our flashlight beams, often floating up and down as they sally to capture an insect in their cavernous mouths. It is a surreal experience, this night work. I often feel like I’m floating from location to location, but what makes it feel real are the frequent pricks of the mosquitos probing my skin, and the constant sweat on my brow as I hike through the tangled habitat.
Once we catch a bird we immediately take a blood sample, then band it, measure it, weigh it, and finally return it to its nest. Amazingly, many of them stay in their nests after we return them there. It is pretty darn cute – just like putting them to bed. Hopefully they wake up in the morning thinking that it was all a bad dream.
Thanks to Charles for all of the photos!
