In 2008, we put up a Screech Owl nest box in our back yard. Last summer we were thrilled to realize that a pair of Western Screech Owls had indeed nested in our yard, but not in the box. They used the box, just not for eggs and young. This blog follows their life in our yard, and, sometimes, in their box. We named the female, Olive and her mate, Oliver. I hope you will enjoy reading the ongoing story of this charming family.

Monday, December 20, 2010

Dec. 20 - Huge relief

   At 4:35PM this afternoon, Olive hopped up into the opening of her box. At that very moment I was eyeing a large crow's nest in our big oak tree to see if there were any large (& unwelcome) owls in it. Out of the corner of my eye, I saw movement near Olive's box and was so overjoyed to see her, I almost whooped with delight. As I leaped to the scope to get a better look, she just sat there with her eyes closed looking completely at ease and content. She flew from the box at 5:07PM. Just before she left, I asked her to please be careful, to watch out for large avian predators and to come back to the box. I hope she listened.

Great Horned Owl story

   This story has pertinence, so bear with me!  In 1980 or 1981, when I was in graduate school at San Francisco State, a bunch of us went to Los Banos NWR in March or April on a field trip. This area is about 10 miles east of I-5 in the vicinity of the San Luis Reservoir and is a waterfowl migration stop. Great place in fall and winter for ducks and geese. We found a Great Horned Owl nest in a very tall cottonwood tree near the water and we could see that the nest had at least one young in it. We had no means to climb the tree (remember we were young and stupid at the time) so we decided to return the next day to give it a go. During the night there was a terrific storm with high winds in that area. When we arrived at the place of the nest, we were horrified to see that the nest, formerly in a (natural) horizontal position, was in a completely vertical position, perpendicular to the way it should be. We approached the base of the tree and noticed a largish ball of white fluff on the ground with an intact egg next to it. The fluff was a deceased baby Great Horned Owl. As an aside, in my Ornithology class we were required to "put up" 3 dead birds. This phrase means to prepare a specimen to be kept in a museum for possible taxonomic research. Most of the birds we were putting up were starlings (I guess they ARE good for something!), but Dr. Bowman, our prof. said that we could find our own birds if we wanted to.
   So, we took this unfortunate baby owl home with us and I took it to the bio lab to put it up. It caused a bit of excitement in the department because one doesn't often see a dead baby GHO, nor does one see such a creature being dissected. If I remember correctly, the owl was about 8 or 9 inches tall and was covered with white fluffy feathers. I was removing the internal organs when I noticed something big in the bird's crop. I made an incision and out came an intact adult Brewer's Blackbird! Dead, of course. Suddenly there were quite a lot of people in the room to see this! Dr. Bowman said to note down the blackbird's measurements as well as those of the owl and put both birds in formalin. The two birds were in the SF State Biology Department collection for several years after that day, but I'm not sure if they're still there or not.
   I relate this story to illustrate why the presence of a pair of Great Horned Owls anywhere near my yard has given me some serious dyspepsia! Olive is about 8" tall and could easily become a late night snack for a Great Horned Owl whose height varies from 18" to 24!" A Brewer's Blackbird measures from 8-9" tall. So, stay tuned. I'll post tonight about Olive's continuing presence in the box - or about the other possibility. Admittedly, if she doesn't show up in the box, it doesn't mean she's dead. She could have heard the GHO's last night - in fact she probably DID hear them - and may have decided to seek shelter elsewhere. I REALLY want to tell you, though, that she's still in the box!

Dec. 19 - New anxiety

   Each evening as I watch Olive before she leaves the box, I whisper, "Good luck hunting, be careful, and come back!" I know she can't hear or understand me, but it's my talisman for keeping her in our yard. She left the box last night (Dec. 19) at 5:05PM, looking so fierce, but so small. At 10:20PM, as Ivan and I were about to get into bed, I thought I heard some strange kind of music being played outside. I opened the sliding glass door to the yard and, FROM OUR YARD, came the unmistakeable call of a Great Horned Owl. The call was answered by another GHO who was a bit farther away. Great Horned Owls are VERY big and, no joke, they EAT Screech Owls. The GHO's called a couple more times, making me extremely anxious. During their calling, I went outside (it had stopped raining) and said, "Please go away. Normally we would be delighted to have you in our yard, but we already have an owl and we don't want you here." I will be very concerned until I see Olive tonight in the opening of the box!  Even then, if the GHO's stick around, Olive, Oliver and any kids they have this spring would be in great danger.  My fingers are crossed that the GHO's found a lovely nest tree about 10 miles away! I'll post again tonight after I've seen Olive (and given her more serious instructions re being careful).