Earth Day Owlets, 04-22-20

Happy Earth Day!  This is its 50th Anniversary.  I got up at 6:00 this morning and then out the door around 7:00 am to go to the American River Bend Park for a walk with my friend Roxanne.  And, yes, I wore my Earth Day shirt today.  Hah!

 We’d gone mostly to check on the Great Horned Owl and her owlets and to look for Pipevine Swallowtail butterflies, eggs and caterpillars.  Both of us noted that we haven’t seen a whole lot of butterflies in the Sacramento region lately.  We don’t know if they’re late or we’re early.

The owlets were up in a tree together, under and behind some stickery branches and leaves which made photo-taking a little difficult.  We had to walk through the chest-high dew-dampened grass to find some spots where we could see them more clearly.  They kept an eye on us all the while we were moving around their tree.  Mom was nearby in a different tree, her head hidden in the shade.  In the early morning, everyone seemed comfortable, but by the time we checked on the owlets again on our way out of the park several hours later, one of the owlets was panting from the heat.  We hope he’ll be okay…

CLICK HERE for the full album of photos.

While we were watching the owlets, there were some House Wrens singing and fussing around us.  We traced one of them back to its nesting cavity in a nearby tree.  We were surprised by how low the opening one to the ground – just above the level of the high grass. 

We found a couple of Tree Swallow nesting cavities, and next to one of them we witnessed a knock-down-drag-out between several Towhees.  First, a pair of California Towhees routed out a Spotted Towhee and chased it away.  Then a third California Towhee came into the mix and three chased each other around and battled midair around the trees, clashing pretty violently at times.

Tree Swallow, Tachycineta bicolor

According to Cornell: “…Both males and females engage in aggressive behaviors towards other males and females; defense is not sex-specific… Displaying birds often circle each other, fluttering the wing closest to their opponent, occasionally switching directions to flutter the other wing. Birds sometimes pair this display with another, where they pick up small sticks or twigs and hold them in front of their opponents… Males and females vigorously defend breeding territories against rivals, sometimes to the point of bloody injury… In Pasadena, CA, a male attacked and bloodied an intruding California Towhee caught in a trap when the intruder put its head through wire mesh of the trap in an attempt to escape…”

I think it was that territoriality that we were witnessing.  Further reading let me know that both males and females hold territory, and mated pairs usually stay together for five years or more.  And they’re not super-particular in where they nest: on the ground, in shrubs, in trees, in man-made structures… They can have up to three broods per year.

We were also treated to seeing a female Western Bluebird at the doorway to her nest.  The male bluebird was several trees away, guarding his territory, but never came close enough for is to get a photo of him.

A female Western Bluebird, Sialia Mexicana

I saw a White-Breasted Nuthatch gathering plant fluff to line its nest, and also watched a Starling collecting insects in the leaf-litter to take to her babies.  We tried a couple of times to catch the Starlings in or near their nesting cavities, but they’re VERY protective of the sites and wouldn’t come near them when we nearby.  We watched one mother carrying a mouthful of worms and bugs circle around and around the nesting cavity, but never coming near it while we were there.

We did find some Pipevine Swallowtail butterflies.  Most of them were flitting around near the tree tops.  The females we found resting on the ground were pretty battered, wings shredded or completely missing from their frenetic short-lived life.  We came across only a few eggs, but noted that the caterpillars are starting to make their presence known through their communal eating (when they’re young) and black frass. In another week or so, they’ll all be fat and getting ready for their metamorphosis.

Early instar caterpillars of the California Pipevine Swallowtail butterfly, Battus philenor hirsuta

There were quite a few Tussock Moth caterpillars in different instars, mostly on the leaves of the oak trees or trailing on the wind on the end of their strands of silk.  Among leaves of the surviving Stinging Nettles (those that haven’t been mowed down yet), we found several Red Admiral caterpillars; and wrapped in the leaves of the Blue Elderberry trees, we found several Elder Moth caterpillars. Other insect discoveries were Click Beetles, Mosquito Hawks, a Harvestman, katydid nymphs, a Camel Cricket, and others.

At one spot along the trail we noted that the leaves of a wild grapevine were dotted with what we first assumed was dew.  But then we realized that none of the other plants around the grape vine had dew on them.  So, we concluded that what we were actually seeing was evidence of “transpiration”, when a plant sweats the excess water in its system that it doesn’t need and releases it to the air.  This usually happens when the plant is in a growth phase.  Something similar can be seen in some fungi in the form of “guttation”.


Other sightings: among the rocks and gravel along the river’s edge we saw some male California Quails and a jackrabbit.  And a surprise was seeing a bright reddish-orange Flame Skimmer dragonfly resting in the long grass.

Flame Skimmer Dragonfly, Libellula saturata

We walked for about 4 hours and then headed back home, stopping for some iced coffee and a grilled cheese sammich on the way.  Yummy.

Species List:

  1. Bedstraw, Velcro Grass, Cleavers, Galium aparine
  2. Bird’s-eye Speedwell, Veronica persica
  3. Black Walnut, Eastern Black Walnut, Juglans nigra
  4. Black-Tailed Jackrabbit, Lepus californicus
  5. Bur Chervil, Anthriscus caucalis
  6. Bush Katydid, Scudderia furcate [nymph]
  7. California Manroot, Bigroot, Marah fabaceus
  8. California Mugwort, Artemisia douglasiana
  9. California Pipevine Swallowtail butterfly, Battus philenor hirsuta
  10. California Pipevine, Dutchman’s Pipe, Aristolochia californica
  11. California Quail, Callipepla californica
  12. California Scrub Jay, Aphelocoma californica
  13. California Towhee, Melozone crissalis
  14. California Wild Grape, Vitis californica
  15. California Woodsorrel, Oxalis californica  [yellow flowers, clover-like leaves]
  16. Click Beetle,  Limonius canus [brown]
  17. Columbian Black-Tailed Deer, Odocoileus hemionus columbianus
  18. Common Dandelion, Taraxacum officinale
  19. Common Fiddleneck, Amsinckia menziesii
  20. Common Hoptree, Ptelea trifoliata
  21. Common Sow-Thistle, Sonchus oleraceus
  22. Convergent Lady Beetle, Hippodamia convergens
  23. Cricket, Arboreal Camel Cricket, Gammarotettix bilabatus
  24. Destroying Angel Mushroom, Amanita ocreata
  25. Eastern Fox Squirrel, Sciurus niger
  26. Elder Moth, Achatodes zeae
  27. English Walnut, Juglans regia
  28. European Starling, Sturnus vulgaris
  29. Field Madder, Sherardia arvensis [looks kind of like bedstraw]
  30. Flame Skimmer Dragonfly, Libellula saturata
  31. Great Horned Owl, Bubo virginianus
  32. Green Shield Lichen, Flavoparmelia caperata
  33. Harvestman, Protolophus singularis
  34. House Wren, Troglodytes aedon
  35. Interior Live Oak, Quercus wislizeni
  36. Mourning Dove, Zenaida macroura
  37. Mugwort Weevil, Scaphomorphus longinasus
  38. Oak Titmouse, Baeolophus inornatus
  39. Pacific Pea, Lathyrus vestitus
  40. Plum, Prunus cerasifera
  41. Poison Oak, Pacific Poison Oak, Western Poison Oak, Toxicodendron diversilobum
  42. Red Admiral Butterfly, Vanessa atalanta [caterpillar]
  43. Red-Shouldered Hawk, Buteo lineatus [heard]
  44. Rio Grande Wild Turkey, Meleagris gallopavo intermedia
  45. Santa Barbara Sedge, Carex barbarae
  46. Spotted Towhee, Pipilo maculatus
  47. Stinging Nettle, Urtica dioica
  48. Sulphur Tubic Moth, Esperia sulphurella [tiny dark moth with yellow lines]
  49. Tree Swallow, Tachycineta bicolor
  50. Turkey Vulture, Cathartes aura [in flight]
  51. Valley Oak, Quercus lobata
  52. Western Bluebird, Sialia Mexicana
  53. Western Fence Lizard, Blue Belly, Sceloporus occidentalis
  54. Western Tussock Moth, Orgyia vetusta [caterpillar]
  55. White Horehound, Marrubium vulgare
  56. White-Breasted Nuthatch, Sitta carolinensis
  57. ?? spider egg sac