Small Owl Nest Box Project

As part of our conservation role, Puget Sound Bird Observatory is helping to provide safe alternatives to natural cavities by installing owl nest boxes specifically sized for Western Screech-owls and Northern Saw-whet owls.

Western Screech-owl, Megascops kennicottii, and Northern Saw-whet owl, Aegolius acadicus, were once fairly common in the Pacific Northwest, but birders have noted – and available survey counts confirm – that populations of both species are in decline. Speculation on the reasons for decline center on three likely causes: predation by larger owls, competition for cavities with other cavity nesting birds, and habitat loss.

According to Newton, “The breeding densities of many bird-species which nest in tree cavities are in some areas limited by shortage of sites. This is evident from circumstantial evidence in which the numbers of breeding pairs in different areas correlate with the numbers of local nest sites, or where changes in the numbers of nest sites resulting from natural processes or human action are followed by changes in the numbers of pairs. When nest boxes were provided, they were often occupied in the same year, leading to an immediate rise in breeding density. This implied that surplus birds were available in the vicinity and able to take them up.” (Newton, 1994 Biological Conservation, Volume 70, Issue 3, Pages 265-276, The role of nest sites in limiting the numbers of hole-nesting birds: A review).

About the Small Owl Nest Box Project

The goal of this project is to provide safe alternatives to tree cavities by installing nest boxes specifically sized for Western Screech Owls and Northern Saw Whet Owls. The City of Shoreline provided seed money to buy materials for the project and help with nest box installation.

A pilot project kicked off in January 14, 2014. Nest box sites were selected in several City of Shoreline local parks, where mixed forest and riparian or pond areas  provide the perfect habitat for these owls. Over the next few years, PSBO will be monitoring nest box activity and looking to expand the program with additional project support from area partners and agencies.


No volunteer help is needed at this time, but if the pilot project is successful, we’ll be looking for help with box building and monitoring during the next field season. PSBO will be giving informational talks about the project, so stay tuned for dates! For more information, send us an email at .