Tuesday, May 12, 2020

A Pleasant Birding Hike at the Guadalupe Slough

Date: January 11, 2020
Place: Guadalupe Slough Trail, Sunnyvale, California
Coordinates: 37.419145, -122.018314
Length: 5.4 miles
Level: easy

There are numerous hiking/biking trails along the shores of the San Francisco Bay. There are some that I frequent a lot such as the Hayward Shoreline or the Don Edwards NWR, but every now and then I get to check out a different Bay trail. Last month I led our 4H Hiking Project on a hike at the Guadalupe Slough in Sunnyvale. Learning that we'll be hiking by the Bay, Pappa Quail got his birding camera and joined our group.
Our hike as captured by my GPS 
We had a perfect day: sunny and bright, yet cool with a light breeze. We started along one of the facility's canals that directs water to the end treatment ponds before being released into the Bay.

The birds were there right from the beginning but one particular 'bird' had grabbed my attention more than the regular, feathered ones. Pappa Quail had noticed it too. This one 'roosts' in an airbase nearby.
C-130 Hercules
Pappa Quail wasn't distracted for too long from the real birds, which were everywhere we looked.
Scoup, female
Shortly we reached the treatment pond. The water looked as clean as any lake and no smell emanated from the water. The reflection was mirror-perfect.

The pond was belted by thigh-high vegetation, some of which was tule. This keystone species that once dominated all the bay's wetlands and used to be the main material used by the coastal Native Californians is now a protected species growing in a pitifully diminished habitat.
Tule, Schoenoplectus acutes var. occidentalis 
Nowadays too the tule is home to a variety of birds, including the red-winged blackbird.
Red-winged Blackbird, male
At the base of the tule, a green heron laid ambush to unsuspecting water critters.
Green Heron
While Pappa Quail and the elder chika were busy looking for and at birds, I lead the 4H group along the trail, divulging some information about the facility, the bay, and the local nature every now and then. Before long they got engaged with conversations among themselves and I was left alone to appreciate the pretty reflections.

I did point out to them the hill poking up on the horizon - they have all hiked at Coyote Hills before. It looked like a small buttress from where we stood.
Coyote Hills
Above the horizon the sky was busy too. Birds in formations criss-crossed the sky going to and fro.
Mallards in formation
A lone sentinel on a sign post - a Say's Phoebe on the lookout for bugs. I hope it caught many that day.
Say's Phoebe
We continued north until we reached the Bay Trail and turned left (west) onto it. Bikers would zoom past us and each time one of our group would yell "bike!" and all of us, well trained, would squeeze to the side of the trail to allow the bike safe passage.

It was along that trail that we finally got close enough to the main slough, the Guadalupe Slough, that connects the Bay water to the inland system of canals, ponds, and wetlands.

We were going by clamps of tule when the younger chika yelped with excitement and grabbed Pappa Quail's attention to a yellow bird that hopped between the tule stalks. Pappa Quail got very excited and both he and the elder chika were soon busy documenting this little bush bird. It was a common yellowthroat but despite its name, it wasn't so common to see. My young chika was very proud that finally she had contributed to the bird excitement in my family.
Common Yellowthroat
A cinnamon teal in the pond on the other side of the trail added some more color to the avian display.
Cinnamon Teal
It was nice to walk on this trail with the slough to the north and the pond to the south, separated by water from the urban area and all the noise and hubbub. A lot of other people thought the same - the trail was fairly busy. There were also a number of anglers that sat by the slough and passed the time chatting and drinking beer, waiting for something to catch their hooks.

The water of the pond is controlled by a valve and pump. We passed by the pump location which was surrounded by high fence and had a sharp and alert guard in the form of a northern harrier.
Northern Harrier
The harrier wasn't the only raptor keeping watch - the air patrol was carried on by the white-tailed kite.
White-tailed Kite
Past the pump we turned back south following the slough. The slough water was shallower here, and assumed the muddy color of the earth beneath.

Every now and then throughout our hike we could hear gunshots. We speculated that these were hunters, and the speculations turned reality when we saw the hunters returning in a boat from the hunters' blind out in the bay water.

We saw the hunters get off the boat at a launch on the other side of the slough. It might have been that group only because after that the shootings ceased.
Our trail curved to the east again, and split to either the south side or the north side of the slough. We went n the north trail, keeping the slough to our right and the treatment pond to our left. Ahead of us loomed the ig green closed midden, where Sunnyvale's old waste is buried.

Around the curve we had a clear view to the northeast to the currently active landfill site. We were too far to see the cloud of gulls that usually hangs by that place.
The far corner of the ponds was matted with ducks. I was too far away to see which kind.

Turning my gaze a bit more north I saw Mission Peak resting peacefully under a gathering of clouds.
Mission Peak
Pappa Quail and the elder chika were far behind me, having lingered by every feathered creature they've seen. And they've seen quite a few.
Eared Grebe
It's not wonder they took so long to walk this stretch of trail - little bush birds can be difficult to see, let alone photograph.
Song Sparrow

I didn't use to pay much attention to sparrows before Pappa Quail got more serious about birding. They all looked the same to me. Now I know there are many different species of them, but still I have difficulty telling most of them apart. I rely on Pappa Quail and the elder chika for the identification.
Fox Sparrow
This one I had no problems identifying: a coot-like bird with stripes and a red beak. Used to be called a moorhen but the name was recently changed to a gallinule.  I didn't get to see it on that hike, but Pappa Quail did.
Common Gallinule (Moorhen)
I also missed seeing the seal that was swimming up the slough, likely searching for fish. It's quite interesting that they come so far into the bay and even the sloughs and canals that go far inland. I've seen seals far up the Sacramento River and it surprised me less than seeing this one near the waste treatment facility.
Harbor Seal 
Our group was very stretched by now. One of the younger kids and his mother increased their pace. I caught up with them briefly enough for them to tell me that they're hurrying to finish, so I slowed down and let them disappear from my view. The rest of the group took their time in following me. hey enjoyed the day and each other's company. For a while I was all alone.
All of a sudden, one of the boys in the group came running up to me, calling me to go back some distance and see this strange thing in the pond ... well, I followed him, not sure what to expect. When I saw it I grinned - it was a vortex: a proof of the human management of the pond's water level. Somewhere below the surface was an open pipe connecting the pond with the nearby slough, and the vortex is formed by the flow from one to the other.
The other kids came by and stared at the vortex. I drew their attention to Mission Peak and promised that one day I'll lead them up that mountain.

Pappa Quail was still behind me when I commenced walking down the trail. He had a lot of distractions. Good ones.
Ruddy Duck
This was one of the rare hikes in which I found no flowers blooming along the trail. But I did see mushrooms sprouting after the recent rains.

Pappa Quail on the other hand, was having an eye feast. Even common birds that we see anytime we hike by the shoreline were given due pixel space.
Least Sandpiper
He took his time but eventually Pappa Quail got close enough to the duck at the corner of the large pond. They were nearly all northern shovelers.
Northern Shovelers
The main trailhead is at the Sunnyvale waste and water treatment facility. One outcome of this simple fact is a certain odor that hiked with us along the trail segments closer to the facility. Not too bad, and easily ignored and disregarded, but present nonetheless.
we were separated from the trail we started with by a canal where treated water was dispensed into by a line of fountains. We had to turn north and walk along this canal for some distance before reconnecting with the main trail so we passed right by those fountains. Behind the canal - a tower with a red radar constantly monitoring the sky. It's a rather small radar and I wonder if it's monitoring bird activity rather than airplanes.
Canal and radar
There were plenty of birds active in the release canal too.
Snowy Egret
Numerous gulls were twinning between the second and third water release fountains. Nearly all of them were ring-piled gulls.
Ring-billed Gull
After reconnecting with the main trail we turned south toward our starting point. Near the far bank of the slough was a gull that attracted Pappa quail's attention - it was of a species not so common in the Bay Area. How he saw this from the distance we were at, I don't know.
Thayer's Gull
A single crow watched us intently as we passed by the sign post it perched on. It wasn't bothered (or at least didn't show it was) by the people passing by.
American Crow
The Bay Trail split off to continue east, where it curves around another slough and canal, passing through the Alviso unit of the Don Edwards NWR. A pair of kites and a crow perched on a lone, bare tree that stood between us and the pond to the east.

A much nearer coyote brush bush was the perch of a male Anna's hummingbird. Considering how tiny this bird is, it is pretty bold and wears a very domineering air.
Anna's Hummingbird, male
A great blue heron patrolled the vegetation near the edge of the canal, searching the ground and checking us out at the same time.
Great Blue Heron
Then a couple of huge, noisy birds zoomed by, circled overhead and disappeared southwest.Pappa Quail was quick to capture this one too on camera. Apparently this one is an F-35 bomber of the Black Knights.
F-35 Black Knights
When we reached the parking area I had to stay behind with the elder chika while the others decided to go up the trail of the covered midden to look at the view. While waiting behind I looked at the cloud of birds that rose momentarily from the pond and swirled around for a couple of minutes, until the birds resettled on the water.
Before modern settlement in this area the birds would darken the sky, so numerous they were.

Meanwhile, Pappa Quail and the rest of the 4H group ascended the green grass-covered landfill butte. This site is already supporting a biological community, in which the borrowing California ground squirrels are permanent residents.
California Ground Squirrel
Wherever there are rodents there would be the next level of the food pyramid, in this case - a great egret. These would eat anything that fits in their bill and often they'll hunt for field rodents as well.
Great Egret
One can almost believe they're on a grassy East Bay hill with this fauna display on the landfill midden. Ignoring the surrounding urban development, this little artificial hill truly looks pastoral.
Western Meadowlark
Eventually the elder chika and me went up the midden too. There's a really nice view from there (the header photo was taken from the top of that hill), and in the center of photo below the white salt mound in Newark is visible. All this salt harvested in the salt ponds of Cargill Corp.

I actually had to persuade my elder chika to go up the hill. We didn't go quickly enough to catch up with the rest of the group - we saw them completing the hike as we descended from the hill ourselves. By the time we reached the parking lot they were already disbanded.

I suppose this won't be a trail I'll hike frequently, but it was nice to discover and see what vistas and wildlife can be seen at this locale. It was also interesting to read the information signs posted by the Sunnyvale Waste Treatment Facility, explaining their work methods. Most of all, it was the best way to pass that beautiful January Saturday.


  1. Nice hike with many interesting and beautiful birds, but not "last month"...
    The reflection pictures are beautiful!
    The seal is surprising, and the airplanes are a different kind of surprise :-)

    1. That was certainly a hike full of surprises :-)