OWLETS In a Box and Another Occupant

Ken was able to check the owlet box this week; the chicks look healthy and mom is still roosting in the box with them. Both owlets are losing their down feathers and looking more and more like adults as their contour feathers grow. They were more curious about the camera then mom, who has the adult wisdom to avoid predators, lie flat and be still.

This owlet in the box is still pretty downy.

This owlet is slightly older, showing more contour feathers

The nestling phase is about 35 days so they should fledge between the 3rd week and end of June. We were hoping to put up some cameras around the nest box to watch the parents deliver food and the chicks fledge, but the supporting trees were too far away. We'll have to come up with other ideas.

Meanwhile, last week we found another occupant in nest box #2. We have deduced, based on the list of cavity nesting birds in the area, that it was an ash-throated flycatcher egg. Since there was only one egg and it had ants on it, we determined it was abandoned. This weeks' box check confirmed it, no new eggs, more ants.  Here's how Cornell Lab of Ornithology describes the egg, "creamy white with reddish brown streaks and elongated blotches." Click this link for more information about the ash-throated flycatcher. 

OWL IN THE NEST BOX!

Western Screech Owl inside a nest box

Can you see the the owl in the box?  You are looking at the head and back of a Western Screech Owl inside nest box # 15. We believe she is incubating eggs due to her flattened posture and absolute stillness when we peeked the camera into the box. If she is incubating and all goes well, we can expect to see 2-7 nestlings within the next month.

So how did we see her? This winter Ken and crew installed nest boxes to determine potential use of the BCCER as breeding site for Northern Saw-whet owls, a cavity nesting species. To check the nests Ken attached a flexible cable with tiny camera and LED light to a bamboo pole, plugged in to his tablet. He can feed the camera quietly into the cavity entrance, see what is inside on his screen and then take a photo. We have conducted two box checks,

Ken's nest-cam set up. The camera is at the end of the pole
inside box #4. He is viewing the inside of the box on his tablet.

one on March 11 and one on April 19. In March, we found bird feces in two two boxes but no birds were present. We guessed the boxes were used by Northern Flickers roosting in the boxes at night. In April, we found identifying flicker feathers in the same boxes, and then we found the screech owl in a third box, What a fun surprise! Learn more about Western Screech Owls here.

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.

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