This 2014 video from North America is called Northern Pygmy-owl #4 – Staccato Call.
From the NestWatch eNewsletter in the USA, June 2017:
New Birdhouse Plan for Western Owls
Who doesn’t love a tiny owl with a funny name? That’s why we’re pleased to introduce you to four newbies to our Right Bird, Right House site—home to more than 50 nest box plan downloads. Meet the Flammulated Owl, Elf Owl, Ferruginous Pygmy-Owl, and Northern Pygmy-Owl.
These small western owls are some of the least-studied owls on the continent, so we’re providing nest box plans for them in the hope that you can help us learn more. If you live in the correct range and habitat, you might be able to attract them. Accounts of their biology are rife with phrases like “few data exist,” “further study needed,” and “assumed to be…” Data from citizens could help us fill in the gaps.
It should be noted that nest boxes for Northern Pygmy-Owl are considered experimental. To date, they have not been known to use nest boxes, but the closely related Ferruginous Pygmy-Owl and Eurasian Pygmy-Owl do. However, all we need is one person with a nest cam to answer such basic questions as “How long are the incubation and nestling periods for this species?”
NestWatch is extremely grateful to Fred Stille, who worked with us to create the nest box plan for these four species. The plan is based off of a design by Markus Mika, a researcher who studies Flammulated Owls in Utah and Arizona. We thank Fred and Markus for making this plan available online to interested NestWatchers.