Clean out used nest boxes or not?

This beautiful Eastern Bluebird nest is located in our OOEF Nestbox #7 on our Old Oak Estate Farm Bolden Bluebird Trail. The nest features some horsetail hair from our black horse. Photo by Gisela Borawski-Hayes, Belleville, IL, United States

This photo of an eastern bluebird nest is from Belleville, Illinois in the USA.

From the Cornell Lab of Ornithology‘s NestWatch eNewsletter in the USA, September 2017:

Cleaning House…or Not

With the nesting season drawing to a close, our once bustling nest boxes are now quiet and filled with leftover nesting materials. What should be done with old nests? Do cavity-nesting birds prefer to reuse nests, or do they like a fresh start?

Unfortunately, the answer is not clear-cut, and a lot depends on the species and the geographic location. Find out more about whether or not to clean your nest boxes on the NestWatch Blog.