Ebird List Link: https://ebird.org/checklist/S68402485
Date: 05/04/20
Location: Presidio of San Francisco, San Fransisco County ( 37.78738, -122.47458) at an elevation of approximately 243 feet (74 meters). Refer to the map for where observations were recorded.
Site Description: Observations were done along a trail in the Presidio. Some observations were done along a paved path at a higher elevation looking out towards the coast. The majority of observations were done along a dirt path in a densely packed forest with tall gum trees, pine trees, and some grasses. The density of the forest provided a cooler, shaded habitat. The forest also had several dead standing and fallen trees dispersed throughout it. The forest site was at a lower elevation with a gradual hill decline towards sea level. At the forest edge, there was an open-aired area with no trees and only small shrubs. The most abundantly observed species were: White-crowned Sparrows (8), American Crows (7), Anna’s Hummingbirds (3), Red-tailed Hawks (3), Song Sparrows (3), American Robins (2), Barn Swallows (2), and gull species (2). Other species observed were: a Chestnut-backed Chickadee (1), a Common Raven (1), a California Scrub-Jay (1), and a Great-horned Owl (1).
Species Account: I stopped on my walk down the dirt path through the forest to take a seat on a fallen gum tree in the shade. From this spot I had a good visual of the dark dense forest to my right, and the bright open-aired habitat to my left. The skies were clear and the temperature was warmer than usual, so the birds were singing perched in the shade provided by the tall trees. I was having difficulty locating birds, their size was made seemingly even smaller due to the height of the trees. Additionally, they hid and camouflaged so well under the cover of the trees. I was forced to scan back and fourth across the tree tops searching for movement that would potentially lead to a bird sighting. To my surprise, I eventually spotted a rather large bird perched perched close to the tree trunk. At first glance I thought that it must have been a Red-tailed Hawk because that was one of the species I have been seeing consistently when I come to this site. The bird’s plumage was mottled brown, excellent for blending into the tree’s trunk. I also got a briefly glance at the bird’s eyes, which were a sort of glowing yellow color. Both the plumage and eye color were associated with what I had seen when I got good looks at Red-tailed Hawks. However, with further observation I realized that the bird’s features were distinct and that it was not a hawk. This bird’s body was wider than the slender, streamlined body of the hawk. Its eye color was similar to the hawk, but its eyes were much larger with a flattened, circular patterned face. The most defining feature was the little tufts of feathers that stuck out from both sides of the top of the head. With these features and news from other birders seeing owls at this site, I was able to identify the bird as a Great-horned Owl. Great-horned Owls (Bubo virginianus) are of order Strigiformes and of family Strigidae. They are large owls with thick bodies, rounded heads, short bills, and feathered ear tufts. Their plumage is typically mottled gray-brown with a white patch near the throat. Their facial discs vary across regions from gray to cinnamon. Great-horned Owls can found inhabiting a large range of habitats: deciduous and evergreen forests, swamps, desert, tundra edges, and tropical rainforest, as well as cities, orchards, suburbs, and parks. They are a nocturnal species that can primarily be found nesting in trees during the day. These owls prey on a variety of mammals, birds, and reptiles. They capture their prey using their excellent hearing, which is enhanced by their asymmetric faces, and silent, aerial diving. The Great-horned Owl call is described as a deep, stuttering series of four to five hoots. Males and females may be heard engaging in back and fourth hooting duets.
Sources:
- “Great-horned Owl – All About Birds.” Allaboutbirds.Org. https://www.allaboutbirds.org/guide/Great_Horned_Owl/overview. Accessed 5 May 2020
- “Great-horned Owl – Ebird.” Ebird.Org. https://ebird.org/species/grhowl. Accessed 5 May 2020
Narrative: Observations occurred along a trail over 0.67 miles. The weather was sunny with clear skies. The temperature was between 65-70 degrees Fahrenheit. A moderate diversity of species was observed with a low abundance of each. This was likely not an accurate survey of the species dispersed throughout the area, most of my time was spent observing the Great-horned Owl. Over the duration of the trip (59 minutes), thirteen species were observed. The most abundant species that I observed were the White-crowned Sparrows. I noticed that groups of about three to four sparrows were gathering together on bush tops and singing their songs. They jumped from branch to branch but remained on the same bush as their fellow sparrows. The singing behavior and the frequency at which I’m now seeing the sparrows together leads me to suspect that breeding may be occurring right now. On the topic of breeding, when I was walking through the forest area I noticed a standing dead tree that had holes in the trunk large enough for a small bird to enter into. I believe that a small bird species was potentially using this as a nesting site (photo of this can be seen below under additional media and photos). After repeatedly coming back to this site, I noticed that there is always an Anna’s hummingbird that perches at the top of one of the medium-sized trees during warmer days. The tree is located right at the entrance of the trail that I walk on, so I pass it often. I have yet to observe the hummingbird protect its territory from another bird trying to perch on it. A cool behavior I was able to witness was the hunting of a California Scrub-Jay. The bright blue plumage caught my eye in the open-aired habitat, and I watched as the bird dove down to the ground and came right back up with a worm in its mouth. The jay then proceeded to perch on a tree branch to eat his meal.
Additional Photos and Media:
