July 27, 2020
This is a dry, hot time, and when walking out in the valley grasslands and riparian corridors there are many flycatchers eating the abundance of insects that fly up around me. Flycatchers are insect eaters, and today there are families of many different species busily catching food for their fledglings. Each one has their beak full of moths, grasshoppers, beetles, and other flying insects. The two I see in front of me now are the Ash-throated Flycatcher, Myiarchus cinerascens, and the Western Kingbird, Tryannus verticalis.
The Ash-throated Flycatcher sits on the fence as two more land nearby, then a fourth shows up to feed one of them. It has been a long time since I have seen this many of these pleasant looking birds. This bird is larger than the Black Phoebe flycatcher but smaller than a Robin, with a long, slender shape and often peaked crown. It has a whitish throat, yellow belly, rufous tail and wings, and is reddish dull brown on top. I see the rufous wing/tail feathers when they turn away. The adult has a mouth full of insects and flies over to one of the juvenile birds that appears as large as the adult. The other juvenile is begging for food too while the other adult bird flies off to find more insects.
Ash-throated Flycatchers are secondary cavity nesters and will use human-made nest boxes. An interesting fact about them is that about 5% of their nest have snakeskin in them while 98% have mammal fur in them mostly from rabbits! They are tolerant of high temperatures and do not need to drink water, getting their water from the insects they eat, so are adapted for desert or dry environments. These flycatchers have a year-round presence in parts of extreme southeastern California but everywhere else in California they are migrants. They move south during late summer and early fall, departing the United States by mid-September. Most spend the winters on the Pacific Slope from Mexico to Honduras, and so we only get to see these lovely birds for a short time during spring and summer.
The Western Kingbird is also a flycatcher that migrates from Mexico and Central America in early spring to nest in our valley. This is a gray-headed bird with a yellow belly and a whitish throat. Its tail is black with white sides which are conspicuous in flight. They are not cavity nesters but rather the females build a bulky open cup of woven grass stems, rootlets, fine twigs, and lichen. Kingbirds ferociously defend their territories with wing fluttering and highly vocal attacks. I have often seen both male and female pairs chasing away large raptors such as a Bald Eagle, a Red-tailed Hawk, and a Common Raven. I often see them on a high perch such as a tall tree top or an electrical wire, hunting and watching over their territory. Kingbirds are like hawks on insects, catching them acrobatically in the air and sometimes filling their short stout bills to capacity. They will also hunt and eat terrestrial prey like grasshoppers and crickets. Sometimes kingbirds can be seen eating elderberry, hawthorn, and other small berries.
Both species’ populations are stable at this point. However, because they eat insects, they are susceptible to pesticides. There are other perils. The Ash-throated, being a secondary cavity nester, has succumbed to 4-inch metal or plastic standing pipes that are not capped. The fledglings are unable to get out of these pipes after falling in and die inside of them. We have made sure on the mitigation lands that our large fencing, irrigation, and well markers are all capped to prevent this from happening!
As I watch these two species of flycatchers hunting insects, making similar yet quite distinct sounds, I enjoy the grace and subtleness of their colors and outlines. These birds will depart on their long journeys in just a few weeks, heading back to their homes. In the meantime, they will be busy raising their young and getting them ready for independence. The challenges and wonder of this life cycle fill my thoughts as I return to my car.