Renewing Old Love: A Nature Hike in Shadowcliffs Regional Park

Date: July 15, 2024

Place: Shadowcliffs Regional Park, Pleasanton, California 

Coordinates: 

Length: 2.5 miles

Level: easy

I used to frequent Shadowcliffs Regional Park a lot when I lived in the area, but I haven't been there in quite a few years. Last June, when I was thinking of a place to take my family hiking group on an easy summer hike that could be concluded at a swim beach, this lovely little park immediately popped into my mind. I planned a scouting hike to check out what's new in the park, and I invited Pappa Quail to join me. 

As soon as we exited the car I spotted a killdeer bird that looked injured. It wasn't really injured though, but putting on a show - to pull potential predators away from her nest. 

Killdeer

Eventually the bird did get up and started walking normally. Tried as we could with our binoculars and zoom lens, we couldn't see where the nest was. Killdeer, like many shorebirds, lay their eggs in a small depression directly on the ground. The eggs are so well camouflaged, as are the young hatchlings, that it is nearly impossible to see them, unless one knows exactly where they are. 

Killdeer

The area of Shadowcliffs park used to be a quarry. One of the quarried holes was filled with water and is now a lovely lake with a swim beach. The nicest swim beach in the East Bay, in my opinion. Most people who come to Shadowcliffs come for the beach. The park however, does have a nature area as well, with a creek and a lagoon, and pretty vegetation, and a lot of wildlife, especially birds. Hiking trail on both sides of the lagoon allow anglers, dog walkers, and hikers to enjoy the natural treasures of this little park in the middle of the urban area of Pleasanton. 

Our hike as captured by Pappa Quail's GPS

When we reached the trailhead I noticed the first big change since the last time I hiked in Shadowcliffs: a large decorated canopy with shaded benches  was erected at the trailhead, alongside a water fountain. The iron decorations where of local nature scenes and wildlife. and looked very pretty. 

At the trailhead

We didn't stay at the trailhead to enjoy the new canopy but walked right over the low ridge and down to the lagoon below. There we stood for a long while, taking in all that we could see there. 

Shadowcliffs Lagoon

A low bridge spans the lagoon. We paused on the bridge and looked around. The calm, almost still water was covered almost entirely with a sheet of red duckweed, and also large patches of water lily - a cultivated landscaping pond plant that found its way into the wild. They have pretty flowers, and Pappa Quail got a nice closeup photo of one of them. 

Water Lily, Nymphaea odorata

He didn't forget the birds either, and although there weren't many of them there at the time, Pappa Quail found a black phoebe perched on a bent cattail blade by the distant shore of the lagoon. 

Black Phoebe

Past the bridge the trail split: a narrow foot path split off to the left, along the lagoon and into the vegetation, but the dirt road that extended from the bridge ascended up away from the lagoon. I knew what was to be expected on the left so I suggested to Pappa Quail to continue south straight ahead and see what's there. 

What was up above the lagoon was a large flat field of dry wild oats and other weeds that separated the dirt road trail from the edge neighborhood of Pleasanton. Seemingly, nothing all too interesting there. We probably would have turned back down if not for the cackling raucous that emanated from a large eucalyptus far ahead, where the trail exited the park and mat the neighborhood road. It was the sound of a heron nesting community, and Pappa Quail was already on the march to get there. I followed suit. 

I paused momentarily when I saw bindweed blooming between the dry wild oats. Like the oats, this species of bindweed is an invasive species in California. 

Field Bindweed, Convolvulus arvensis

From the south plateau I had a very nice view to the northeast. The hills were dry and yellow, with only one buttress in that direction showing a dark, forested cap - Brushy peak. I remembered the hike I did at Brushy Peak Regional preserve last March when it was all green and lush. 

Brushy Peak

When I approached the end of the trail I saw that Pappa Quail was already focusing his camera up on the eucalyptus tree. There were many nests there, visible to the naked eye as well. There were many great blue herons there also, but it looked like none of the birds were sitting in the nest at the time. Apparently, the nests were still in their building stages and the birds were still in their courting and fighting stage,. They were sure making a lot of noise. 

Great Blue Heron nests

Herons were flying in and out of the tree. We saw the big birds carrying nesting material on their way in.

Great Blue Heron

The big eucalyptus was outside of the park and across the neighborhood road. In fact, it was growing in someone's back yard. I wondered how are the house owners tolerate the noise and the defecation (it smells pretty bad) but when we crossed the road I noticed a canopy and telescope that were set under the tree. Clearly the owners were just as fascinated with the nesting colony as we were. 

Great Blue Heron

After observing the herons colony for a while we turned about and reentered the park. I took in the view again - now that of the ridge where the Morgan Territory Regional Wilderness was. 

Morgan Territory

Pappa Quail looked at a sight much closer than the Morgan Territory ridge - a young bluebird was perched on a sign post making sure that park goers would know about the parkland rules. 

Western Bluebird, juvenile

We didn't need to go back on the same dirt road we came up on - the park's trail continued past the neighborhood gate down toward the southeast side of the lagoon. At the bottom of a short and dusty slide the trail was level again. Right beside the trail stood a really large buckeye tree, at the very end of its bloom tome. 

California Buckeye, Aesculus californica

There were still some die-hard flowers, pretty much all male, hanging stubbornly on the inflorescence still, but the scent and the butterflies were already gone. 

California Buckeye, Aesculus californica

Other trees such as the cottonwood, which were closer to the lagoon - the source of the water, looked much more lively and vibrant. 

Between the lagoon with the line of riparian vegetation that belted it and the trail we were walking on was a field of drying weeds. This field was home to many little critters, including little bush birds, which kept Pappa Quail busy for a few minutes. 

House Finch

Between one bird to another, Pappa Quail also found a pretty dragonfly that stood resting on one of the dry thistle plants near the trail. 

Dragonfly

Pappa Quail spotted also three young bluebirds who were squeking on a bare branch over by the vegetation belt. We waited for a minute or so to see it their parents would show up but they didn't and and moved on. 

Bluebirds, juvenile

We continued slowly along the trail. The day turned pretty hot, and we were constantly wiping the sweat from our faces. There was very little shade on this part of our hike. 

Trail

The buckeye might have been at the end of its bloom season, but the elderberry was just peaking at the time we were there. The combination of dried buckeye wood and elderberry branch shafts were the favorite fire-making kit of the native Chochenyo tribe (now grouped with the Ohlone Nation) of the east bay.  

Elderberry, Sambucus mexicana

South of the trail a bit away and partially hidden in the oak trees, was a human-made white nesting box, probably designed for owls. We didn't see any activity there and we didn't approach it to look any closer, in case is was occupied. 

The trail stretched ahead going back west to where the bridge was, This was our trail to return to the north side of the lagoon but I noticed a narrow foot path branching off directly north to where the water was, and I wanted to check it out pulled Pappa Quail to follow it. The first thing we notice was the relief of being in the shade. The second thing was an American Robin in the vegetation. Pappa Quail ignored the robin - it is too common a bird here. I photographed it, though. I wanted to remember that it was there. 

American Robin

The trail reached a small clearing by the water. Although the trail there wasn't an 'official' trail - there was no junction sign and it is not marked on the park's trail map,  we did see a memorial bench there. Another person was sitting on the bench, so we took a few quick photos and moved on, not wishing to disturb the fellow in this quiet nook. 

Reflection

Under the trees that flanked the lagoon the ground was completely covered with low vegetation comprised mainly of brambles and poison oak. The blackberries were of two species - the invasive Himalayan blackberry, and the native California blackberry. The Himalayan blackberry was transitioning from flowers to fruit, and all the berries we saw were green and hard. 

Himalayan Blackberry, Rubus armeniacus

The California blackberry was much further along. There were no more flowers to be seen and most of the berries were red. I was happy to find some berries that were already black and ripe for the picking. They tasted really good, too. 

California Blackberry, Rubus ursinus

I guess this path we were on used to be official park trail at some point because after wandering around a little we did see an old sign post. The post had no sign attached to it anymore, but it made a perfect perch for a western fence lizard. 

Western Fence Lizard

When we were done exploring, we exited the brambles and the trees and continued west all the way back to the lagoon-spanning bridge. There we stopped and looked about us again, for now there seemed to be more birds around. 

Mourning Doves

It was an hour difference between our first stop at that bridge and the second one. Now there were many more birds hanging around that area. 

Turkey Vulture

While Pappa Quail was busy scanning for birds I took closer attention to the willows nearby. I already noticed that the inside trails, as well as all the low vegetation, was covered with seed fluff that made everything look eerie. Most of the seed fluff came from the cottonwood, but at least some, came from the willows.

Willow, Salix sp. 

Pappa Quail joined me and we moved on east again, this time on the north side of the lagoon. This path was much closer to the lagoon than the south side trail. There were also many more trees there that cast shade, providing some relief from the heat.

Trail

The seed fluff was everywhere. In fast, I had to take care to not inhale any. The layer of it on the ground was so thick it could have been mistaken for snow, or if one considers the heat, for cotton candy.

The fluff hat hung from the dead branches was much less snow-like and more like dense cobweb. The entire trail looked ready for Halloween.

For a short while Pappa Quail and I were walking at a good pace. Then Pappa Quail saw a movement in a cottonwood tree, and we stopped again for the flycatcher that he spotted. 

Ash-throated Flycatcher

Most of the trees growing by the lagoon were wild trees of a riparian (river side, fresh water loving) community.  Shadowcliffs however, is in the middle of what used to be farmland, then suburban area, and there are cultivated trees here and there, throughout the park.

Red Plum

Farther east the trees opened up and revealed the lagoon, wide and calm. Here most of the water surface was open, free of surface vegetation. A few anglers were standing in strategic places near the water, their lines cast in the lagoon, waiting for fish to bite on.

In places where vegetation did cover the water, we saw some waterfowl enjoying the safe and sunny perch. 

Mallard, female

We continued walking slowly along the lagoon. There weren't many bords there, other than a few mallards near the shores. 

There were plenty of active insects however, and thankfully they were the beautiful types such as dragonflies and butterflies. We did have to deal with a few mosquitoes, though. 

Dragonfly

Before long we were back under the trees. Earlier on the hike we came across another hiker which, upon seeing our cameras, informed us that there was a large eucalyptus tree ahead with a nesting colony of egrets. There was no problem identifying this tree when we got to it. It was somewhat smaller than the previous eucalyptus we saw in the neighborhood south of the park, so there were fewer nests on it. But the tree canopy wasn't as dense and we had a much better view of the nests and the birds that were nesting there. 

Great Blue Heron

Clearly, not all the birds there were egrets. There were at list two nests of great blue herons on that tree. Other nests however, were of great egrets, and they seemed to be quite farther along that the nests on the previous colony we saw. There were some nicely fledged chicks in a couple of the egrets' nests. 

Great Egret, fledgling

There were relatively few adult birds in that tree. Perhaps they were busy foraging. After all, they had growing youngsters to feed. 

Great Egret

After giving due attention to the herons and egrets in the nesting colony on the tree, Pappa Quail pointed at the lagoon where he spotted a green heron. The heron was perched on a partially submerged piece of wood in the middle of the duckweed covered water and was difficult for me to see because it was camouflaged so well (no, it's not in the photo below but left of the frame). 

I needed the binoculars to see the green heron standing there. We watched it for a while until it took off and flew out of our sight. 

Green Heron

The trail curved and ascended up the levee. I took one more photo of the calm lagoon and we resumed our hike up the trail and back into the heat of the direct sunlight,  

Up on the levee was another trail junction. Instead of looping right back we took a little extra loop around what was marked on the map as a pond, hoping to see some wildlife there. The pond turned out to be more like a puddle of standing water, surrounded by trees that blocked most of the view. The birds we did see there were not in the water but on the nearby trees. 

House Finch

We circumvented that pond and went up on the levee again. The trail side north of the pond was trimmed well - perhaps to control rattlesnakes. 

I was glad to see that not all vegetation was trimmed near that trail. An effort was made to not harm the patch of California poppies that bloomed near the trail junction. The bumblebees were grateful too. 

California Poppy, Eschscholzia californica

From the height of the levee we had a broad view southwest of the tree that hosted the egret nesting colony. It was very obvious why the birds preferred nesting there, it was prime real estate, the best tree around. 

Heron and Egret Nesting Colony

The view north had Mount Diablo, clear, aloof, and majestic. Mount Diablo is one of my favorite Bay Area places to hike at, although the height of summer might not be my top season of choice for hiking there. Below us was the Shadowcliffs lake where the swim beach and the boat marina were. 

Mount Diablo

To the south we had a nice view of the area we hiked earlier - the lagoon, the neighborhood above it, and the large eucalyptus with the great blue heron nesting colony. From where we stood, we simply continued west on top of the levee to where the trail descended back into the parking lot. 

Lagoon

Flanking our trail on the north was a thick line of tall sweet fennel plants that were at the height of their bloom. The fennel attracted many insects and I took the time to look at some of them. 

Bumblebee on Sweet Fennel, Foeniculum vulgare

Bees and butterflies swarmed the fennel, both flowers and foliage. I too snapped some small young leaves to chew on. 

Swallowtail butterfly on Sweet Fennel

Another domestic tree that I've seen in places along the hike was the almond. The fruit were green but already too hard and fibrous to eat as is.

Almond, Prunus dulcis

I did catch one more native California wildflower on the levee before going down - the Spanish lotus. I almost missed it because it was low to the ground and partially hidden by the dry weeds that towered over it.  

Spanish Lotus, Acmispon americanus

When we returned to our car I dropped the backpack there and informed Pappa Quail that I was going to check out the women's restroom, carrying the camera along with me. From previous visits there I remembered that barn swallows liked nesting inside the restroom building, that had partially open roof. Sure enough - the swallows were there. A single nest with four hungry fledgelings and a parent (or two - I couldn't tell them apart and there was only one at a time) that swept by every minute or so to stuff something down the throat of a chick. 

Barn Swallow

Not too far from the swallows nest was a very different kind of nest - that of wasps. From a safe distance it is actually a pretty fascinating thing to see. 

Wasp's Nest

Pappa Quail, who followed me to the recreation area near the beach stayed outside of the restroom building and documented the male house finch that watched guard over the beach. 

House Finch, male

It was a lovely little hike and it was so hot when we finished it that we went right back home after that. On the following weekend it was even hotter so I moved the family group hike to the week after that. It was hot still, but manageable. The nests were still there, which was was I wanted to see and to share with my group.