This video from the USA is called Great Crested Flycatcher Calls.
From the Cornell Lab of Ornithology in the USA, April 2017:
Wanted: Great Crested Flycatcher Nest Photos
Great Crested Flycatchers have a curious habit of adding snake skins to their nests. But, why do they do this? If you find a Great Crested Flycatcher nest this spring, take a photo and submit it to NestWatch to help us understand this unusual behavior. We’re collaborating with Dr. Vanya Rohwer of the Cornell University Museum of Vertebrates to address three main questions:
- Does the use of snake skins in nests vary across the breeding range?
- Where in the nests do flycatchers place snake skins (e.g., touching eggs, around the entrance hole, or scattered throughout the nest cup)?
- Do snake skins increase nesting success?
How to take photos: Great Crested Flycatchers are cavity nesters, so these directions assume that you’ve found a nest in a box. Please take photos looking straight down onto the nest so that the nest cup, eggs/nestlings, and box walls are visible. For each photo, please include the location, the date you took the photo, and indicate whether you’re NestWatching the box (data on nest fates are especially helpful). In order for photos to be used, they must be in focus and sufficiently bright so that we can see snake skins inside the nest (or lack thereof). Please submit photos through our online Participant Photos Gallery.
Great Crested Flycatchers are an insectivorous bird that is declining in some parts of its range. If you live in an area with an open forest habitat (urban or suburban neighborhoods with mature trees, old orchards, lake or riverside areas with large shade trees) in the eastern or midwestern states, you can put up a nest box to attract Great Crested Flycatchers. For the best chance of success, avoid placing the nest box in open agricultural areas or dense forest.