Friday, January 20, 2017

ATTENTION SAW-WHET OWLS - Nest Boxes Available!

Ken Sobon and team have installed over 15 nest boxes on the Big Chico Creek Ecological Reserve (BCCER). He is hoping that the boxes will attract saw-whets, perhaps those wintering on the Reserve or moving through in spring, will stay and nest. If a pair does-it would be the first documented saw-whets breeding on site! We haven't done any summer surveys so we can't say they don't breed here. Generally I think the Reserve is too low in elevation (and hot) for Sierra Nevada breeding habitat, but these owls are shown to be nomadic, meaning they will breed where conditions are right (good prey, micro-climate) and don't often return to the same breeding area.
Locations of seven nest boxes on the Reserve. Also see our two banding sites, OWL2 and OWL3. The structures include barn workshop, office and old ranch house.The forests provide cover and good roosting habitat for owls and the meadows are great habitat for foraging for rodents.
You can see the boxes are distributed around, mostly under good canopy cover and near meadows for foraging and all boxes face NE (cooler). Some are on different tree species, some near small drainages, some with a different slope aspect.  It will be really exciting to check these boxes. Other cavity nesters that might find the boxes homey are western screech owl, ash-throated flycatcher, northern flying squirrel, wood rats and???  Monitoring begins in early March. Stay tuned!
This box #8 will be under a fairly dense cavity when the oaks leaf out.
You can see the canopy closure in the aerial google earth photo above
taken in late May.

Wednesday, January 18, 2017

Let's Get it Started! Nest Box Program for the 2017 NSWO Breeding Season

New project co-director Ken Sobon is moving forward into the breeding season for owls. We don't know if NSWO breed on site, but we have captured them as late as 4 April, likely during spring migration. We have made limited attempts during the late spring, early summer to identify nesting birds, with negative results. BUT this species is opportunistic and considered to be nomadic, nesting where the prey base and other conditions are right, and not necessarily returning to the same nesting area. Habitats on the Reserve could be good for saw-owl breeding in some years.

Ken's nest box building team, hoping to entice saw-whet owls!

Drilling the "cavity" entrance
Ken and his team may be monitoring for years before
actually finding a breeding owl, or it could happen this spring. If he does find a saw-whet it will be the first documented nesting on site. He might also find other cavity nesters using the boxes including Western screech owl, American kestrel, ash-throated flycatcher, northern flying squirrels and ??? Check back to our blog!

Ken installing nest box #5

Tuesday, January 10, 2017

New Project Directors Ken Sobon and Julie Newman 2017

Welcome Ken and Julie as the Northern saw-whet owl fall monitoring project's new directors. What a great journey it has been and a privilege to pass the project along to these two dedicated volunteers. Ken is the VP for Altacal Audubon Society (our project sponsor) and Julie is a professional environmental scientist. Both have banded and participated with the project for several years.
Ken Sobon, NSWO project Co-director
Julie Newman, NSWO project Co-director

Long-term monitoring of a species is essential to understand population trends and local natural history. Thank you for continuing this important work. Great team! 

Tuesday, November 22, 2016


We had another great season with 57 new NSWO and 8 same season recaptures. The  owls arrived steadily and we only dipped one night, so 17 out of 18 nights of effort, we banded owls. There were two peak migration nights on November 1 (8 owls and 1 recapture) and November 16 (8 new owls!).
A trio of owls could indicate family members flying together.
On these peak nights we typically capture multiple owls in one run and there is current DNA research to determine if these may be siblings or family members migrating together. The eight same season recaps is our record for recaptures in one season. They stayed on the property between 6 days and 26 days and may continue to winter on the Reserve. Their overlapping and continued presence and good body weight indicates a healthy prey base (rodents) for so many owls.This year we had several chunky owls with a good amount of fat and weights over 100 grams! Fat, which can be seen as a yellow layer under the skin, is an important fuel for migration and cold winter nights.
This individual has 3-4 generations of feathers, noted by the different colors in the
blocks of feathers; she is over 3 years old
We have also noted that the older birds tend to migrate later (we capture them later in the season), probably because the young of the year disperse early from their natal area. On our last banding night we banded this older female with several generations of feathers. These birds can be challenging to age, but it is great to see that some owls survive seasons of migration and breeding.

Thank you volunteers Julie Woodruff, Ken Sobon, Julie Newman, Wyatt Hersey, Erika Iacona, Maureen Morales and Kim Armstrong, for another great season of owl monitoring, season 12!!!!

Sunday, November 6, 2016


One of our project's goals is to educate people about Saw-whet owls. On Friday we got to introduce an owl to a group of 8 girl scouts and two moms (Troop 70079). My colleague at the US Forest Service, Maria Cisneros, organized this group so we were representing the USFS, Altacal Audubon Society and the Reserve, a great team! Wyatt, one of the owl banders, entertained the girls with moon, stars and wildlife stories, Maria shared binoculars, headlamps, flashlights, and treats and I even got to tell a spooky ghost story. Perfect under-the-milky way conversation! And then came an owl.......

Troop 70079 at the BCCER with Maria Cisneros (USFS) and Wyatt Hersey (Altacal)
 On our last run, voila! there she was, all feathers and golden eyes. So our conversation went to ooohs and aaaahs and the value of owls in the ecosystem, the importance of forests and snags for their breeding, Reserve habitats for migration refueling and wintering, owls as individuals and their amazing feathered toes, large asymmetric ears and keen vision. The saw-whet cast her spell again and left 8 girls, no doubt dreaming about owls!

Showing the numbered USGS bracelet (band, bling!) that we place
on the owls tarsus to identify them as individuals.
All smiles! Our owl is in the middle of the picture. Next step, RELEASE!

Sunday, October 30, 2016


We had a very interesting night last night netting 7 owls! 3 of those owls were recaptures from 3 different previous nights, the most same season recaptures I have ever caught in one night. The owls were banded 10, 8 and 6 days prior.These owls are using the Reserve as a restful migration stop, or may winter on site if they prey base (mice and voles) are good.  Most owls this year are quite chunky with good fat reserves and high body mass. It is good to know they are eating well!
 Milk Chocolate Owl
The owls are always unique but some individuals really stand out. Last night we banded this very richly plumed brown and buff owl. The juveniles are brown so I was thinking she retained some juvenal plumage but no, she was a second year bird, and just unique in color. A very beautiful owl!

Ken holding the Chocolate Owl before release

Thursday, October 27, 2016


Unpredictable is a synonymous word for Northern Saw-whet Owl! 1-5 owls per night since we started this season, and then, on the most perfect night, in the peak of the season- 0 owls! But here we are with 22 owls almost 1/2 way through the season.We never know what will happen next but this is what the year looks like so far, 22 owls:
Two owls, maybe migrating together? 
October 5- 1 owl
October 12- 1 owl
October 16- cancelled due to rain
October 17- 5 owls
October 19 -3 owls
October  20- 5 owls
October 21- 3 owls
October 23 - 4 owls
October 24- cancelled due to rain
October 25- cancelled due to rain
October 26 - 0 owls!