I got up around 5:00 this morning so the dog and I could do our potty stuff…and then I stayed up, getting ready to go over to Mather Lake Regional Park for a walk with my friend and fellow naturalist Roxanne. The weather was lovely today. It was about 59° when we got to the lake and then creeped up to about 88° by the late afternoon.
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When we got to the park, the first thing we noticed was that the Mute Swans seemed to be gathered in a corner near the walking trail on the far side of the lake. The cygnets are just about as large as their parents now, but they’re still making their baby peeping sounds, and they don’t have their full facial coloring yet. We were sad to see one of the swans floating dead among the rushes.
We met a fisherman later on during our walk, who said that he had seen another younger swan who looked dead on the shore, and when he went over to it, he found that was severely tangled in fishing line. Line remnants are a BIG problem on the banks. Even today, while we were walking, my feet got tangled in the crap on two different occasions. Some of the lazier fishermen just don’t clean up after themselves and leave discarded line everywhere. It’s such a hazard.
Anyway, one of the adult swans was chasing and nipping and trying to herd the younger swans into a corner, even as their parent tried to put its body between them and the aggressor. The aggressor bird “busked” and chased after the parent and eventually drove it halfway across the pond before giving up its assault. While that was going on, the younger swans were peeping loudly at one another, trying to get to their mom who was being chased off, and obviously very distressed by the attack.
Additionally, one of the other adult swans, who apparently wasn’t related to the youngsters, just didn’t want to get involved and stepped up onto the bank next to me. You don’t realize how huge those birds are until they come up next to you. They can get up to 5 ½ feet long and weigh around 30 pounds.
This one was quiet and polite, just a sort of “go with the flow” kind of bird, but further along the trail, we came across another parent and its youngsters, and it was very protective of them. It raised its head and hissed at me a couple of times to get me to back off.
My impression of the aggressive bird what that it was “being a jerk”, a bully. But then it occurred to me that the dead swan was in the same area where the aggressor was putting on its display, so I wonder if was trying to “protect” the dead bird or at least the area where the dead bird was located.
We also saw two color morphs among the juveniles, and I’d never seen/noticed that before. According to Cornell: “…Cygnets hatch as gray or white. Gray [Royal] cygnets become brownish as juveniles and begin molting to white by first winter. White [Polish] cygnets remain white as juveniles and adults. Gray juveniles usually retain some gray feathers , especially on rump, until following molt. Legs and feet of cygnets and juveniles are either slate gray (gray morph) or pinkish tan (white morph). Bill color of juveniles also varies between morphs: gray morph, slate; white morph, tan. Bills of both morphs become pinkish as they mature during winter. Basal knob is absent in cygnets and relatively small in juveniles. Lores of newly hatched cygnets are feathered, but during first winter, a juvenile’s lores become naked…”
As an additional aside, Cornell also says: “…Two views exist as to whether or not being a white morph (see Distinguishing Characteristics above) is advantageous. Several experiments using models determined that whiteness elicits aggressive response in adult Mute Swans and is therefore disadvantageous. These findings are consistent with the large amount of anecdotal evidence that suggests that white cygnets are at a disadvantage because they are perceived as threats to their parents’ territory. Another view is that being a white cygnet is advantageous because female cygnets that enter their first winter already in white plumage will be able to pair with older males and eventually gain breeding experience over their gray counterparts, therefore gaining reproductive advantage over gray morphs…”
The juveniles we saw being crowded and nipped at by the busking adult were all white ones… All of the gray morph youngsters we saw were in the water and pretty far away, so I wasn’t able to check them out too closely. The gray ones looked to be the same age as the white ones, so I’m assuming they all hatched around the same time.
And another feature: the knob, that protuberance at the base of the top bill where it connects to the head. According to Cornell: “…Males generally have larger knob than females. During breeding season (Jan–Jun), knob of adult males is enlarged, and breeding males have larger knob than nonbreeding males.” Some of the guys we saw were pretty “knobby”.
Among the birds, besides the swans, we saw Great-Tailed Grackles, Pied-Billed Grebes, tiny fast-moving Bushtits, Double-Crested Cormorants, Brewer’s Blackbirds, Canada Geese and a few others. The coolest sighting of the day, even though I wasn’t able to get any photos of it, was to see a White-Tailed Kite chasing and buzz-bombing a Red-Tailed Hawk that got too close to its territory. The birds moved pretty fast, and my camera doesn’t know what to focus on when I point it at the sky, so… no photos. Waaah!
We did get to see a Green Heron standing on a thin floating log in the water, and got to see it catch a tiny silvery fish. Some of the swans swam right by the heron and either didn’t see it or weren’t interested in it. When we first saw it, the heron was back-lit and just looked like a stick poking out of the water, but some close-up photos showed it was actually a bird. We had to walk down the trail a bit to get the heron in better lighting so we could get a few better photos of it.
There weren’t anywhere near as many dragonflies as I thought there might be given all the water and the time of year, but we still have about month or so to go in the season.
I didn’t find a single example of dragonfly or damselfly exuvia along the water’s edge either, which was also an indicator of how disappointing spotting dragonflies was going to be. Oddly enough, Roxanne did find the exuvia of some kind of cicada among the leaves of a coyote brush bush.
We also saw some stem galls on the coyote brush and four different kinds of galls on the willow trees along the water’s edge: pinecone galls, rosette galls and a couple of different blister galls. Those are always cool to see. On the side of the lake we were on there weren’t many oak trees, beyond the cork oaks, so we didn’t come across any oak wasp galls. The next time I go out, I want to check out the opposite bank and see what, if anything, is on the trees there. Among the cone galls, I was surprised to see some of them in clusters of six, eight and nine. I don’t remember seeing bunches that large before.
I was able to spot at least three different species of bee while I was out there, most of them feeding on the thistle flowers, and a couple of different kinds of wasps.
The really nice treat was being able to see two very large Western Tiger Swallowtail butterflies feeding on the thistle nectar. Roxanne had stopped to point out a dragonfly on the ground, and I alerted her to the “giant butterflies”. Hah! Luckily, the dragonfly, a green female Pondhawk was still sitting on the ground when I stepped away from the butterflies to look for her.
We walked for about 3 ½ hours and then called it quits for the day.
- American Bugleweed, Water Horehound, Lycopus americanus
- Anna’s Hummingbird, Calypte anna
- Barn Swallow, Hirundo rustica
- Belted Kingfisher, Megaceryle alcyon [in flight, heard]
- Black Phoebe, Sayornis nigricans
- Black-Crowned Night Heron, Nycticorax nycticorax [in flight]
- Blue Dasher Dragonfly, Pachydiplax longipennis
- Brewer’s Blackbird, Euphagus cyanocephalus
- Broadleaf Cattail, Bullrush, Typha latifolia
- Bull Thistle, Cirsium vulgare
- Bushtit, American Bushtit, Psaltriparus minimus
- California Bulrush, Schoenoplectus californicus
- California Quail, Callipepla californica [glimpsed, heard]
- California Scrub Jay, Aphelocoma californica
- California Wild Rose, Rosa californica
- Canada Goose, Branta canadensis
- Cicada, Typical Cicadas, Subfamily: Tibicininae
- Common Gallinule, Gallinula galeata
- Common Sunburst Lichen, Golden Shield Lichen, Xanthoria parietina [yellow-orange,on wood/trees]
- Common Vetch, Vicia sativa
- Cork Oak, Quercus suber
- Cottonwood Leaf Gall Aphid, Pemphigus populivenae
- Cottonwood Petiole Gall, Poplar Petiole Gall Aphid, Pemphigus populitransversus
- Coyote Brush Stem Gall moth, Gnorimoschema baccharisella
- Coyote Brush, Baccharis pilularis
- Double-Crested Cormorant, Phalacrocorax auratus
- Eurasian Collared Dove, Streptopelia decaocto
- European Starling, Sturnus vulgaris
- Familiar Bluet Damselfly, Enallagma civile
- Floating Water Primrose, Ludwigia peploides ssp. peploides
- Fremont’s Cottonwood, Populus fremontii
- Goodding’s Willow, Salix gooddingii
- Great Black Wasp, Sphex pensylvanicus [saw it flying low to the ground]
- Great-Tailed Grackle, Quiscalus mexicanus
- Green Heron, Butorides virescens
- Harvester Ant, Pogonomyrmex sp. [black]
- Himalayan Blackberry, Rubus bifrons [white flowers]
- Mallard duck, Anas platyrhynchos
- Mourning Dove, Zenaida macroura
- Muskrat, Ondatra zibethicus [got a glimpse of one]
- Mute Swan, Cygnus olor
- Narrowleaf Willow, Salix exigua
- Northern Flicker, Colaptes auratus
- Northern Mockingbird, Mimus polyglottos
- Nuttall’s Woodpecker, Picoides nuttallii
- Pacific Forktail Damselfly, Ischnura cervula [males blue, 4 dots on thorax]
- Paper Wasp, European Paper Wasp, Polistes dominula [black & yellow]
- Pennyroyal, Mentha pulegium
- Pied-Billed Grebe, Podilymbus podiceps
- Red-Tailed Hawk, Buteo jamaicensis
- Red-Winged Blackbird, Agelaius phoeniceus
- Soft Rush, Juncus effusus
- Spanish Clover, Acmispon americanus
- Squarestem Spikerush, Eleocharis quadrangulata
- Swamp Smartweed, Persicara hydropiperoides
- Tall Flatsedge, Cyperus eragrostis
- Tarweed, Fitch’s Tarweed, Centromadia fitchii
- Tree Swallow, Tachycineta bicolor
- Tripartite Sweat Bee, Halictus tripartitus [tiny, striped abdomen]
- Tule, Common Tule, Schoenoplectus acutus
- Urbane Digger Bee, Anthophora urbana [looks like a pale blond and white bumblebee]
- Waterweed, Common Waterweed, Elodea canadensis
- Western Kingbird, Tyrant Flycatcher, Tyrannus verticalis
- Western Pondhawk Dragonfly, Erythemis collocata [males are blue; females are green]
- Western Tiger Swallowtail, Papilio rutulus
- White Tailed Kite, Elanus leucurus
- Willow Apple Gall Sawfly, Pontania californica
- Willow Bead Gall Mite, Aculus tetanothrix
- Willow Pinecone Gall midge, Rabdophaga strobiloides
- Willow Rose Gall Midge, Rabdophaga rosaria
- Yellow-faced Bumblebee, Bombus vosnesenskii
- ?? Tiny pale jumping spider
- ?? Small unidentified grasshopper