Every Wednesday

Lyn writes:

So I'm out in my garden at dusk minding my own business on Wednesday, April 2. I hear the hawks but it is a different, more urgent cry. I look up and see a hawk alight on the top of the deodara, which is to the east of and lower than the Canary Island pine with the nest. A second hawk, presumably the male, comes down on top of her and flap-flap-flap-flap-flap-slam, bam, thank-you ma'am, then he's up, up and away. She is prostrate at the top of the tree for about five minutes, her head and back one continuous horizontal silhouette. Recovered, she sits upright for another five minutes or so, and then is gone.

Tonight, Wednesday, April 9, Mont and I were enjoying the evening with its purpling sky and its fingernail moon when we heard a staccato cry from a hawk who flew straight to the top of the deodara, followed closely by the male who flapped-flapped on top of her for a few seconds--definitely a briefer and more perfunctory tryst than last week. Likewise, she maintained her post-coital stupor for a much shorter time, recovered and flew away.

Was this the same male as last week? She definitely led him on, right to the same spot as last week's deed. Does this mean she will nest here near the scene of passion? Stay tuned for next Wednesday.

An Exciting Sighting

They're back! We think.  While Mont was hanging up his laundry this morning, he heard a hawk up in the top of the nest and rushed inside (followed closely by Lyn and Elizabeth) to look at the video camera.  Sure enough, a hawk was sitting smack dab in the center of our manufactured nest, facing the camera.  The hawk (he or she, we aren't sure) stepped gingerly from side to side as if trying things out, while the three of us frantically tried to figure out how to record the live video feed.  We only succeeded in disrupting the broadcast, so that although we could still watch the video recording, we couldn't get it to broadcast to the website.  But after about five minutes, the mystery hawk took to the air again, to be joined by another hawk.  They are definitely a nesting pair.  For the next half hour they circled the garden, landing in a tall oak tree at the back of the property.  Unfortunately, they were too high up to get a decent picture.  However, we will figure out how to record the camera signal, so that when (hopefully) they come back, we will at least be able to post some movie clips.  Ideally, we will be able to watch them build their nest, and record the process.  

When Will They Return?

It has been two weeks since we replaced the nest. According to Birding Northern California by John Kemper, Swainson's hawks return to Yolo County sometime in March. We have a bet about when the hawks will return. Mont has already lost. Elizabeth has her money on St. Patrick's day. Pat took the safe option, March 20th or later. 

Nest Eye View of the Camera

This photo was taken from just behind the nest looking back toward the camera, with Pat in the background. Beyond the grapevines of the nest in the foreground, is the inverted camera dome mounted on the wooden frame which  protects it from wind and rain.  

Bird's Eye View of the Nest

This photo was taken from the top of the western leader, giving a view of Mont, Elizabeth and the nest similar to what a curious turkey vulture must have seen when she passed by just a bit later. 

View From the Top

 We were so high, you really couldn't see our yard at all.  In the first picture (above) is a view to the southeast.  As you can see, we are near open agricultural fields which makes this an ideal nesting location for Swainson's hawks, who need plenty of open space for foraging.  In the second photo (upper right), you can see the Dave Pelz bike bridge crossing the Interstate 80 freeway, as well as the houses of our neighbors to the north, the Brunner-Clevingers and Calfees. Kent Calfee can attest that voices travel unobstructed from treetops.  He reported overhearing several inadvertent expletives while he was gardening on this sunny afternoon. At first he thought it was a disembodied voice. Then he realized the voice was coming from the top of a tree a block away.   The last picture (right) is looking down on Pat's backyard.  Pat was amazed at how tiny his enormous Valley Oak tree looked from this height.

Three in the Tree

Once the nest platform was safely in the treetop, Pat (right) followed Mont (upper right) up to the top of the tree.  Again, Elizabeth monitored the video feed and directed the positioning and orientation of the nest platform so that it could be seen on the computer.  Then she (above) joined them to help anchor the nest platform securely in place using wire inside sections of garden hose (to protect the tree branches from being girdled by the wire).  With Pat along to help, the job was done in no time, and we could take our time to enjoy the view.  

This enlarged photo shows the relationship of the camera to the nest.

Replacing the Nest

When Dad was tied in at the top of the tree, he set up the pulley again, and hauled the tools and the nest up to the top.  The photo on the right shows the new nest on its way up the tree.  Then he belayed Pat up to the top, and the two of them positioned the new nest in place of the old one, while I watched on the video from the computer and directed where exactly to place it so it would be in full view of the camera.  The photo on the left was taken by Pat from just below the top, in between the two leaders.  You can clearly see Mont and the camera in the western leader, and the nest perched in the top of the eastern leader.

Third Trip Up the Tree

So once again Mont scaled the tree.  Here he is getting ready to climb, and starting up the tree.  Elizabeth was belaying him from below.  For this climb, the expert photographer is our neighbor, Pat, who had heard so much about our exploits that he wanted to climb the tree with us.  With his help, we were able to get the new nest up in the tree and firmly anchored, all in one afternoon, with plenty of time for documentation, and just admiring the view.

Making a New Nest Platform

The making of the new nest platform was an interesting problem.  We wanted something that would be fairly sturdy and could be securely anchored to the tree, but that would look as nearly as possible like the real thing.  We had a number of wreaths of varying sizes that Lyn had made over the years by weaving grape vines together.  Mont selected a range of sizes and arranged them in concentric circles to form the bottom and sides of a large, shallow dish.  He wove the wreaths together using green privet sticks each bent in a u-shape.

Storms Destroy the Nest

We were very excited to see whether our Swainson's hawks would actually return yet again to the same nest.  We didn't know whether they would be bothered by having the camera a few feet away.  We had tried to camouflage it with pine needles and branches when we first put it up, but the first few storms of January washed all our hard work away, and we noticed on the video camera that the position of the nest was changing.  It seemed to be slipping off the branches and in danger of falling down.  Then at the end of January there was a pretty big storm, that caused numerous power outages, downed trees, and blew the the rest of the nest completely away.  We were very disappointed, and didn't know if the hawks would return, now that there was no home to return to.  But Mont talked to Ron Walker, a local expert on Swainson's hawks, who said that having their nests blow down is a common occurrence.  Swainson's hawks can rebuild a nest in a single day, and often do.  Ron suggested anchoring a platform where the nest used to be that would give them some support, and a more secure place to rebuild the nest that wouldn't blow down in a high wind.  

Installing the Camera

Actually getting the camera into the tree took so long we had to make two separate climbs, and we didn't have much time for picture-taking.  On the first day, Mont lead-climbed to the top of the tree while Elizabeth belayed him from below.  Then he rigged a pulley to pull up the camera and tools that she would load into the bucket at the bottom.  Here's a good picture of the bucket pulley from a later climb.  Mont screwed the camera platform to the three branches, and then hauled up the power cable and coaxial cable in the pulley bucket and connected those to the camera.  

Then he belayed Elizabeth up the tree, and she took both cables and unwound them after her as she climbed down.  Elizabeth connected the other end of the coaxial cable to a cable extension that ran into the house and connected to the computer. She plugged the power cord into an outlet at the side of the house.  Once the cables were connected, Elizabeth could watch Mont on the video feed on the laptop in Mont's office and, communicating by cell phone, tell him exactly how to point and angle the camera so it would be aimed right at the nest.  Mont made the necessary adjustments, but it was getting almost too dark to see, so he had to climb down.  

The next day he climbed up to the top again, checked the orientation again, and then tacked the power and video cables to the tree as he made his way down.  The coaxial cable wasn't long enough to go all the way down the trunk and over to the house, so we anchored the cables to a big limb about halfway down the tree, and stretched them straight over to the corner of the house, and grounded them using the ground for the house power lines.  

Hardware and Software Details

The camera (with remote pan but no tilt or audio) is an analog home surveillance model (PanDome SecurityMan) with coaxial output and requiring 120V AC power at the camera. The analog camera output is routed through a 150' coax cable, converted to digital video(DV) using an ADS PYRO A/V link, fed through a firewire cable to a Mac PowerBook G4 laptop and then captured using the free program QuickTime Broadcaster. The DV stream is broadcast to the server at 15 frames/sec with 320x240 resolution. We're using a server  at the University of California, Davis in the LAWR department. The server hardware is also a Mac laptop running Mac OSX  Server. It uses the program QuickTime Streaming Server configured to reflect the live video as a unicast stream to each client computer on the internet. 

Camera Location

Here is the triad of branches at the very top of the tree where we attached the camera.  

The Original Nest

This picture of Elizabeth by the nest was taken from the western leader.  You can see the nest looks just like a big haphazard heap of twigs, branches and pine needles about 3 feet across.  What you can't see very well is that in the center there's a little bowl-shaped depression only about ten inches across.  It's a perfect half-sphere lined with mud, moss, and soft grass, set into this huge mess of random branches and twigs.

Head in the Clouds

Here's Mont standing nervously in the western leader of the tree with his head above the top. The photo was taken by Elizabeth from behind and below the nest in the eastern leader. We chose to mount the camera in the triad of branches near his left knee, about 42'' from and 18'' above the nest. 

Scouting climb

Our project began with our first trip up the tree in November.  We wanted to have a look at the nest and see if there was a likely place to position the camera so as to get the best view.  The tree in question is a 96-foot tall Canary Island Pine that is by far the tallest tree in the neighborhood and probably the tallest tree in Davis.  

From the top it certainly looks like there's nothing else that even comes close to the same height. The view from the top of the tree is truly incredible.  Not only can you see most of Davis, but on a clear day you can see Mount Diablo(70 miles to the south), the Sutter Buttes(70 miles to the north), the Sacramento skyline, and the sierras beyond it(100 miles east).

Twenty-five feet from the top of the tree, the trunk splits into two leaders that continue pretty much straight up and stay fairly close together (they are only about 5 feet apart at the very top).  The hawk nest was built in a triad of branches at the top of the eastern leader, and there was a corresponding triad at the top of the western leader(which is a little taller) a few feet above the nest, which was a perfect place to position the camera.