Northern Saw-whet Owl Season Summary 2021
at the Big Chico Creek Ecological Reserve
Ken Sobon directed the 16th year of Northern Saw-whet Owl Migration Monitoring and 5th year of the Nest Box Program at the Big Chico Creek Ecological Reserve (BCCER). He did not conduct winter or spring sampling due to Covid-19 restrictions.
2021 NSWO Fall Banding
During fall migration, banders Ken, Julie Newman, Erika Iacona and Maycee Hash and a dedicated group of volunteers netted a total of 94 saw-whets. They had two significant recaptures from previous falls: a female from 2019, and a female from 2017, both four years old! They recaptured four same season owls between 11 and 25 days from their original capture date, showing the Reserve offers good wintering habitat. As usual, females (n=65) were most abundant, and we had just over 50% more hatch year owls (n=49) than adults. The crew banded 23 nights between 09 October- 22 November. Ken banded 10 owls on opening night, the maximum for a night during the 2021 season. Other high capture nights, 7-9 owls occurred during the typical peak dates between 28 Oct.-7 Nov. Banders canceled nine nights, due to rain, but captured more owls per 100 hours of field effort than in 2019, 20 vs 16 (Figure 1). They also captured one unbanded Western screech owl.
Nest Box Program
Although no boxes have been occupied by NSWO, for a fifth year, female Western screech owl band #200 nested in Nest Box #15 and produced four owlets that Ken banded in late spring (Figure 2). She has successfully fledged 16 young since 2017! Males do not incubate eggs or brood young but deliver prey to the female to feed the growing nestlings. Because we have not banded the male, we can’t confirm that #200 has the same mate, but pairs may mate for life.
An Owl Surprise
Our monitoring program is valuable to document the NSWO population, but we also document other owl species on the BCCER. On October 28, Ken documented the first ever Barred Owl (Strix varia) calling near the Reserve barn. It was an expected occurrence, but also a surprise as to when, because individuals have been observed in Forest Ranch, north of the BCCER, randomly over the past several years. Barred Owls have expanded their range from the eastern US. They are large and opportunistic predators and known to take saw-whet owls from nets at other monitoring sites, so diligence is necessary when they are around.
What’s up with the Weather?
Weather is a likely factor influencing the NSWO populations, and certainly impacts our banding efforts. In 2021, the crew canceled nine nights due to rain. Site opening temperatures were typical from mid-40’s to mid-60’s, compared to 2020 temps when Ken documented the highest net opening temperature of 83*F on 16 Oct with several others at 70 plus*F in 2020.
Community Outreach; a Virtual Revolution!
Again, this season, COVID-19 restrictions limited our public outings to a few small groups. One of Ken’s students came out with his “grandma” Carol Anderson, (a fellow science teacher, Altacal member, and banding volunteer), and was thrilled to meet his very first NSWO (Figure 2). Due to the popularity of Zoom meetings and Ken’s previous virtual YouTube presentation last year, he was invited to share more programs in 2021. These included six Audubon Societies, Mendocino, Yolo, Fresno, Redbud, Peregrine and Altacal, watched by over 900 viewers!
Project Support and Volunteers
Logistical support continued this year from Chico State Enterprises and Altacal Audubon Society. Licensed banders were Project Director Ken Sobon, Julie Newman, Maycee Hash and Erika Iacona. We could not do this project without our returning skilled banders/volunteers Charlie Giannini, Mary Muchowski, Brenda Sobon, Kim Armstrong and new volunteers Asher Perla, Jose Martinez, and Fiona Gillogly. We are grateful!!