Northern Saw-whet Owl

Northern Saw-whet Owl at BCCER by Mel Richardson

Why study Northern Saw-whet Owls?

Initially these successful predators were thought to be uncommon; they just weren’t detected due to their nocturnal and cryptic behavior, small size, and nomadic lifestyle. But research now tells us saw-whets are one of the most common forest owls in North America.  Because of long-term monitoring by Project Owlnet cooperators, we have learned about the owls’ migratory behavior all across the Canada and the central and eastern US. What has been missing are monitoring stations in the western US, and that’s where we come in. Our research is conducted at CSU Chico’s Big Chico Creek Ecological Reserve (BCCER) and includes the following components:

Ken installs nest box at the Reserve

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Summary Results of Fall Migration Monitoring Project 2005-2015

In 2005, we established a Northern Saw-whet Owl (NSWO) fall migration monitoring program at BCCER. You can find the published results of the project in the Central Valley Bird Bulletin. In summary, we banded over 550 owls, about ½ were hatch birds (hatched the same season that they were caught) and slightly more were adults. We found that young birds arrived about 3-4 days before adults overall. The median date of fall arrival was 30 October. More than 70% of owls were female, which is typical at all NSWO banding stations. We recaptured 2% of owls in subsequent fall, winter and/or spring. The oldest owl based on recapture was four years old. None of the birds we banded were recovered elsewhere – but we had two foreign recoveries, birds originally banded at other stations. They were from Montana and Iowa!  The owls captured the hearts of many community members who visited our project. With our well-trained group of volunteers, we are in our 13th year of mist-netting and banding owls (2017).  Go here for great pictures of owls and project posts!

Northern Saw-whet Owl male, ready for release

More about Northern Saw-whet Owls!

Altacal’s Northern Saw-whet Owl Monitoring:

Cornell Lab of Ornithology, Birds on North America account for Northern Saw-whet Owl:

Project Owlnet, continental–wide Northern Saw-whet Owl monitoring effort:




Northern Saw-whet Owl’s are threatened by timber management practices (Rasmussen 2008) and Global Climate change. Saw-whets are cavity nesters and prefer older forests for nesting with a more open understory for foraging (Rasmussen 2008). Retention of snags, even small snags with cavities could be critical to the owls nesting success.

As for wintering habitat, the National Audubon Society (NAS) considers the Northern Saw-whet Owl a “climate threatened” species. Their climate change model predicts a 99% loss in wintering habitat by 2080, expecting the habitat to shift northward, with the owl potentially disappearing with it in the lower 48 states during winter.

Continued studies such as the long-term migration monitoring project conducted at the BCCER could be important to reveal local NSWO population trends as our climate warms and our logging practices change. To obtain a clearer picture of NSWO population in the west, our results should be compared with other stations regionally. Our contribution to the continent-wide Project Owlnet, will remain valuable in understanding the trends of this North American species. Maybe just as importantly is our outreach component to the project. Many people will never see a saw-whet because of their secretive nature. We believe that those who do meet the owls, will certainly become more aware and become advocates for owls and their habitat.


Garcia, Dawn, 2017. Fall Migration and Other Natural History Observations of the Northern Saw-whet Owl in Northern Interior California, 2005-2015

Rasmussen, J. L., S G. Sealy and RJ. Cannings. (2008). Northern Saw-whet Owl (Aegolius acadicus), The Birds of North America (P. G. Rodewald, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America:

Shaw, Julie, M.  2014. Winter ecology of northern Saw-whet Owls (Aegolius acadicus) in the Sierra Nevada foothills of California. A Thesis of California State University Chico.

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