Thursday, October 31, 2013

More Owl Mysteries with a Goatsucker Thrown In

In the family of "goatsuckers", I first starting seeing these small birds hunkered down on the ground at night at the Dipper Ranch after we put a thick layer of gravel on the driveway.  
After the interesting comments on the driveway owl - whether it is a great-horned owl or a western screech owl - I want to share more owl photos.  Especially a small owl that shows up at the Newt Spring and then a goatsucker that surprised me on the driveway tonight.

Those night critters.

Little owl at the Newt Spring on September 14th.  
Here's a small owl that showed up on the trail camera at the Newt Spring about once a week in August and September this year.  From the comments of my "owl friends" on the last post, I learned the clever trick of measuring something in the photo to get a perspective on how large the bird is.  And then looking up the sizes of the various owl species.  That board the owl is sitting on is 1.5" thick and the height is 11.5" from the water (darkest line below the board). Sibley has the length (from bill tip to tail tip) of northern saw-whet owls as 8" and northern pygmy owls as 6.75".

No 'ears' on this owl. September 14th owl again.  
The Moultrie 880 trail camera takes black and white night photos so I can't really make out all the fancy details that are shown in the field guides. But the face does seem to have wide discs around the eyes.

Small owl standing on a small post in the corner of the Newt Springbox on August 18th. Probably a northern saw-whet owl.    
No false eye-spots on the back of the head on this owl (something the tiny pygmy owls must need to scare away the bully great-horned owls?), so I am going with northern saw-whet owl on this bird.  What do you think? That means there is an even smaller owl out there for me to find someday. Cool.

I would definitely describe this owl as "shockingly huge" thus a great-horned owl. At the Newt Spring in June.
Here's another owl that showed up right next to the Newt Spring on the BirdCam (which has flash for color night photos) on June 27th. Chunky = great-horned owl. At about 5:00 am this morning, I heard two great-horned owls singing a duet to each other in the maple trees right outside my bedroom window. They court out there every winter. As the nights go by, they get louder and louder in their hooting at each other until finally they move down to the tall Douglas firs along an ephemeral stream and seem to calm down. I guess that is when they start their nest. Some nights, they make such a racket in those maple trees, I can't sleep so I go out and visit them.

When Paul Noble censused owls at the nearby Monte Bello Open Space Preserve in 1986 and 1987, he found the different species of owls associated with vegetation types as a percentage of the total times observed/heard like this:

Northern saw-whet owl -
     Broadleaf evergreen forest 4%, riparian 16%, meadow 0%, Douglas-fir forest 80%.
Northern pygmy owl -
     Broadleaf evergreen forest 5%, riparian 30%, meadow 0%, Douglas-fir forest 65%.
Western screech owl -
     Broadleaf evergreen forest 98%, riparian 0%, meadow 0%, Douglas fir forest 2%.
Great-horned owl -
     Broadleaf evergreen forest 31%, riparian 0%, meadow 25%, Douglas fir forest 39%, chaparral 5%.

The Newt Springbox is covered by a narrow band of large oaks and California bays (=broadleaf evergreen forest) surrounded by grassland. I don't remember any Douglas firs at this location. But as a water source, it could be considered riparian-like. The fence post that the western screech owl/great-horned owl was on in Caught Me Singing at the Gate was along the gravel driveway that has a large grassland on the downhill side and a few large canyon oaks on the uphill side.

Barn owl in August.
Here is a barn owl at the Dipper Ranch. It is in a barn. That was easy.

Nest box built into the barn for the barn owls.
Someone built a box in the interior apex of the barn's ceiling which has a hole and perch to the outside. The barn owls nest in this box. I have seen a similar box built into another local barn and it had barn owls too. Has anyone else seen these boxes? I guess the farmers liked the barn owls eating all the rodents attracted to the barn. No rodenticides, right?

A goatsucker, probably a common poorwill, on the driveway on April 29, 2011.
Finally back to the "goatsucker". It was sitting on the gravel driveway tonight. It was at nearly the same location I saw a similar bird in April 2011. Tonight I approached it very slowly and the bird did not move so I could get a less blurry photo. I am going with common poorwill on this bird. What do you think? The poorwill was on the driveway very near where I often see a large owl on a fence post. It's the driveway that keeps on giving.

Tentatively identified as common poorwill on the night before Halloween. This view gets a little more of the top of the head.
If you like owls, the docents at the Midpeninsula Regional Open Space District often lead nighttime owl hikes at Monte Bello Open Space Preserve in the summer.  Check out the hikes on the open space website next summer. I've gone on them and learned stuff. Plus it is fun running around outside at night with your "owl friends".

You will probably see some night critters today. I hope they are friendly.
Common poorwill, Phalaenoptilus nuttallii
Great-horned owl, Bubo virginianus
Western screech owl, Megascops kennicottii
Northern saw-whet owl, Aegolius acadicus
Northern pygmy-owl, Glaucidium gnome or G. californium
Barn owl, Tyto alba

Paul L. Noble, Distribution and density of owls at Monte Bello Open Space Preserve, Santa Clara County, California. San Francisco Bay Bird Observatory. Western Birds, 21:11-16, 1990.


  1. About the barn owl boxes: Yes, I think they're fairly common. The UC Davis Raptor Center even has instructions on how to build one.

  2. Wonderful poorwill shots. Didn't know those were around here.


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