Tawny Frogmouth nest failure
I’m sorry to have to report that one of the nests has failed. Nest failure isn’t uncommon with Tawnies. Even at the best of times the nest is flimsy, often nothing more than a dozen or so twigs laid across a horizontal fork in the branch. A strong gust of wind will dislodge the platform, sending the young chicks to the ground, but chicks can simply fall off, and I’ve heard that parents can even accidentally knock the chicks out of the nest.
I’ve attached a photo of a typical Tawny Frogmouth nest. As you can see, there’s not much to see.
I found two dead chicks at the base of the tree a few mornings ago. Being your typical birdo, I took a close-up photo of one of the chicks and asked on the Birding-Aus Facebook page to confirm my ID. The chick was about 10cm in length from beak to tail, and was covered in white down, with no feathers visible. Clearly it was a very young chick.
However, I haven’t attached the photo, because, well, it’s a bit sad. If you want to see it, it's on the Birding-Aus Facebook page.
I hope the pair will raise another clutch, but they’ll have to repair the nest platform or the risk of a second failure will be just as high.
Why do Tawnies have such a flimsy nest? Zoologists think it’s probably to do with temperature regulation. Nesting in a hollow might overheat the chicks, to the extent that the risk of nest collapse is preferable to the risk of, er, shall we say “ fried chicken”? Tawnies’ feathers provide excellent thermal insulation, even in direct sunlight.
Incidentally, I got some good additional information about Tawny Frogmouths in Körtner and Geiser, “Roosting Behaviour of the Tawny Frogmouth”, which was published in the Journal of Zoology (Volume 248, Issue 4) in 2006.