Date: April 27th, 2020 – https://ebird.org/checklist/S68137885
Location: North Los Altos, CA – 37.383, -122.114 – Elevation: 45m/132ft
Site Description: This week I elected to go birding in a friend’s backyard because the yard is large and has many tall trees, smaller shrubbery, and open grass available for birds to move around in. Also, this backyard typically has lots of insects, so I was hoping that birds may be drawn to this yard or this area in general to feed on the insects and catch them mid-air. This yard also shares a fence on three sides with other large yards containing an excess of wildlife and shrubbery, so I see lots of birds pass through this yard and the neighboring yards often. There are also many power lines nearby as well as taller trees than can be seen from the yard. On this morning, I was able to see three American Crows on a power line that ran across a street only two houses over. I also was able to spot many swallow species including the Tree Swallow (2 individuals), which has an iridescent blue coloration on the backside paired with a sharp white chest and underside area, and the Barn Swallow (2), which appears cone-shaped when perched and has a slightly flattened head, no visible neck, and broad shoulders that taper to long, pointed wings.¹ For the Barn Swallow, the tail extends far beyond the wingtips and the long outer feathers give the tail a deep fork; this species has a particularly cool wing patterning from above when the wings are spread during flight. I was able to see several Bushtits (6) moving quickly through the dirt covered areas and small bushes and foraging on the ground. This has become one of my favorite bird species as I have proceeded through this class because they are very round, small, and cute. They are tiny, kinglet-sized birds that are very pump and large-heads with no visible neck and short stubby bills. They are smaller than a chickadee and have a relatively drab coloration all over – the ones that I spotted on this morning were very clearly Bushtits and easily identifiable based on their shape (small, round, plump), and behavior (moving quickly through vegetation in a group, continuously making soft chips and twitters). It’s always fun to observe their foraging behavior as they frequently hang upside down and grab small insects and spiders from leaves. I was not surprised to see this species in this yard because Bushtits are commonly found in heavily wooded areas within suburbs and this particular backyard has lots of plant life and tall trees.² I spotted two Ruby-crowned Kinglets and two White-crowned Sparrows, which I had seen before in nearby backyards and was not particularly surprised to see on this day. The Ruby-crowned Kinglets were easily identifiable based on their morphology consisting of a tiny stature, a large head, almost no neck, and a thin tail. They are olive green birds with a prominent white eyering and distinct white wingbar contrasting the dark colors next to it. The ruby-crown was not visible until I was looking at this set of birds for quite some time, so I almost mistook it for a Hutton’s Vireo, which has a very similar coloration and morphology pattern besides the ruby crown. The White-crowned Sparrows are a group of birds we have been seeing since the beginning of the semester – they are large and grey-ish as compared to other Sparrows and have a long tail and small orange-yellow bill. The most identifiable pattern on this bird is the very bold white and black strips that run from the front to the back of the head. They are very clear to see because they are contrasted by the mottled brown coloration that appears all over the rest of the body. Three species that I had not yet personally witnessed and I was more surprised to see on this morning were the American Robin (1), Cedar Waxwing (1), Yellow-rumped Warbler (3). American Robins can be seen in yards and expanses of greenery, particularly where earthworms and others of their favorite foods can be found, so it was not surprising to see them on this day. They are very distinctly colored with a “warm” orange color on the breast and grey-brown backside. They also have a very distinct sing-songy call that can be easily identified after hearing once or twice. The Cedar Waxwing is a bird I have had my eye out for during these past few weeks since we should be seeing more of them during this migratory time. This bird was easily identifiable because it had a short neck and wide bill coupled with a unique coloration – they exhibit a pale brown color on the head and chest which fades to a soft gray on the wings and to a pale yellow on the underside.3 There is a narrow black mask on the face which is neatly outlined in white. I believe this bird had one of the most fascinating color patterns I’ve seen – the coloration that fades delicately from one color to another and combined with the distinct outline on the head is beautiful. The third species I had not expected to see was the Yellow-rumped Warbler. This was a species I had not yet seen in person, but I knew to look out for the yellow coloration on the rump and underside. The ones I saw were very grey and exhibited a patterning with lots of grey all over combined with very minimal white on the wings and the backside in general. There was some yellow around the face area and near the base of the wings, but I did not get the change to see the yellow of the rump before the bird flew away. According to the regional differences, the subspecies that I am seeing is called the “Audubon’s” Warbler, which is local to the Mountainous West as opposed to the “Myrtle” Warbler of the Eastern U.S. and Canada.4 Pictures below show the environmental conditions of the backyard where I went birding, including lots of vegetation, alongside an image of a Barn Swallow, American Robin, Cedar Waxwing, and Yellow-rumped Warbler.
Species Account: Tree Swallow – Tachycineta bicolor (Passeriformes > Hirundinidae) The tree swallow is a very common and widespread bird that tends to be found in various habitats, most often in fields and wetlands. Adults have a coloration that appears as an iridescent blue-green that tends to be much more dark in poor lighting with a bright white color patch on the underside. Immatures are much less distinctly colored than adults tend to be and females are duller with more brown in their upperparts.5 Tree Swallows have blackish flight feathers and a thin black eye mask. Tree Swallows are often confused with bluebirds because of their distinct blue coloration. Tree Swallows can be distinguished from their close relative the Barn Swallow based on their tail shape – Barn Swallows have long, deeply forked tails, unlike the shallow forked tail of the Tree Swallow. Barn Swallows also have reddish throats and peachy bellies.6 Tree Swallows are streamlined small songbirds with long, pointed wings and short, squared or slightly notched tails. Their bills tend to be short and flat and their relative size is slightly larger than a Bank Swallow, but a typical size for a Swallow species in general. The foraging behavior of the Tree Swallow is targeting small, aerial insects that are captured in their mouths during acrobatic flight. They often forage low over water or fields and may pick items from the surface of the water while flying. They can be observes perched in bushes to eat berries and sometimes feeding on the ground especially in cold weather. Their diet consists of mostly insects (especially in the summer) and some berries. They feed on many beetles, flies, winged ants, and others. Also may eat spiders, and will eat sand fleas. Unlike other Swallow species, Tree Swallows eat much vegetable material – bayberries are the main plant food. After breeding, Tree Swallows gather in large flocks to molt and migrate together and in the non breeding season, they form massive communal roosts. Tree Swallows can be found many places – they breed in open habitats such as fields and wetlands, usually near water.7 They tend to nest in artificial boxes as well as tree cavities. Foraging flocks are commonly seen over wetlands and water. The male Tree Swallow arrives on nesting territory before female and courtship involves the male showing the female potential nesting sites. Tree Swallows often choose new mates each year. Natural nest sites are in holes in dead trees, or in old sapsucker holes in live trees, but often also make use of nest boxes. Tree Swallows have a relatively wide distribution that spans North America including the United States, Canada, and parts of Mexico and Central American countries. Tree Swallows migrate north relatively early in the Spring and southward migration begins as early as July, but peaks in early fall. They can be seen migrating by day in large flocks. Tree Swallows are somewhat commonly seen in backyards and places frequented by larger groups of people, which is why I was able to spot two in the backyard of a friends house on rest on the skinny branches of a small tree in the corner of the yard. They looked like they were scanning the area and ready to take off at any moment to catch insects mid-air. The first thing I was able to notice about the morphology of the pair of birds was the iridescent blue coloration on the back side, which led me to believe that I may be seeing bluebirds. However, after taking a second look, I was able to notice that the body shape looked much more like a swallow. I was especially able to see the distinct body shape and wing shape when one of the birds took off in flight. After investigating which swallows have this distinct coloration patterns, I was able to positively identify this pair of birds as two Tree Swallows. Below you can find two distribution maps of the Tree Swallow and several views of different Tree Swallows, including the last photo which is a view of a female with much more subtle coloration (hardly any blue).
Narrative: I began birding this week in my friend’s backyard at around 9:06am on April 27th and stopped birding 138 minutes later. I witnessed 9 bird taxa during this period of time and many of the species were gathered in lower shrubbery and trees as opposed to in the open grass like I had observed in my own backyard. I saw the most about of birds in dense trees and bushes, but also saw a number of birds in taller trees and along power lines, fences, etc. I’ve been improving on my skills of identifying birds based on their calls, which has aided in my ability to positively ID birds after having guesses as to which species I am seeing based on morphology and coloration. I did not fulfill my goal of birding at various times throughout the day, but I hope in my future independent birding endeavors I am able to diversify the birds I am seeing and the locations I am targeting as well as the time of day when I am electing to go birding. Although I have seen a lot of birds in various habitats throughout this semester, I didn’t get the chance to see some bird species multiple times, and I would like to be able to see the in-person view of many of these birds numerous times as opposed to pictures and drawings. The weather on this morning was sunny with a high of 75°F and a low of 49°F8. At the point when I was birding, the weather was warm but comfortable. I don’t imagine this weather was extremely uncomfortable for bird species, but I don’t think I saw as many birds as I was expecting to see after being outside for this amount of time.
Additional Photos & Media: See below photos for additional images of the bird habitats in my friend’s backyard.
Sources:
¹ “Barn Swallow Identification, All About Birds, Cornell Lab of Ornithology.” , All About Birds, Cornell Lab of Ornithology, www.allaboutbirds.org/guide/Barn_Swallow/id
² “Bushtit Identification, All About Birds, Cornell Lab of Ornithology.” , All About Birds, Cornell Lab of Ornithology, www.allaboutbirds.org/guide/Bushtit/id.
3 “Cedar Waxwing Identification, All About Birds, Cornell Lab of Ornithology.” , All About Birds, Cornell Lab of Ornithology, www.allaboutbirds.org/guide/Cedar_Waxwing/id.
4 “Yellow-rumped Warbler Identification, All About Birds, Cornell Lab of Ornithology.” , All About Birds, Cornell Lab of Ornithology, www.allaboutbirds.org/guide/Yellow-rumped_Warbler/id.
5 “Tree Swallow.” eBird, The Cornell Lab, https://ebird.org/species/treswa.
6 “Tree Swallow.” Audubon, 29 Dec. 2019, www.audubon.org/field-guide/bird/tree-swallow#.
7 “Tree Swallow Identification, All About Birds, Cornell Lab of Ornithology.” , All About Birds, Cornell Lab of Ornithology, www.allaboutbirds.org/guide/Tree_Swallow/id.
8 Pelmorex Weather Networks Inc. “Los Altos, CA Window._config.masthead_has_content = True;” The Weather Network, www.theweathernetwork.com/us/last-24-hours/california/los-altos.San Rafael, CA Monthly Weather.”