So, what are Mimic Thrushes? These are medium sized, slender, thrush-like appearing birds, that mimic the songs of other birds in their territorial songs during the nesting season. We have three mimic thrush species that nest on the Nature Preserve lands. The first species that I knew as a child is the Northern Mockingbird.
Unlike many species of birds that we knew as children that have become rare or disappeared altogether, the Mockingbird has adapted extremely well to urbanization.
Currently there are mockingbirds nesting on the Nature Preserve, as well as along
Griffith’s Lake Road, along the railroad behind Walgreen’s, near Parson Thorne Mansion, and behind the doctor’s office on Lakeview Avenue in Milford to name just a very few locations.
The Mockingbird is a light gray slender bird with a broad white patch on the wings and white borders on the tail. During the nesting season it declares its territory with a song which consists of phrases mimicking other birds with snatches of original material interspersed. Each phrase is repeated 6 or more times, moving on to the next selection without pause. Sometimes he may seem to get stuck, almost, and continue a particular phrase 12, or more times. If I listen carefully, I may pick up a few birdsongs that I know, like Bluejay, Killdeer Plover, or Bob-white Quail, plus many others from some exotic, unfamiliar place. I am sure that an expert on birdsongs can identify many, many more.
The song is offered from a favorite perch, elevated branch, rooftop, or TV antenna, during the day and sometimes through moonlit nights as well. Before the advent of air-conditioned houses when cooling was accomplished via open windows, I actually knew a farmer who shot the singer off his roof to deal with his insomnia.
The Mockingbird conceals the nest in the thickest cover of branches. Unless you are observant, they are easy to overlook. Typically, it chooses a site 4-10 feet above the ground. The nest is constructed of coarse twigs, lined with plant stems and grasses, and a final cup of fine rootlets. Usually four, pale blue-green eggs, heavily speckled with brown blotches are laid. Only the female incubates while the male sings.
The Mockingbird is a permanent resident on Delmarva. In winter they become especially tame and can be seen feeding along our forested edges and hedgerows on fruits of sumac, juniper, privet, and rose.
The Gray Catbird was my grandmother’s particular favorite. Maybe because it is the most sociable of the mimic thrushes during the summer nesting season. They were always hopping around her large, shaded yard uttering their distinctive “mewing” call note that gives the bird its name.
The catbird is slightly smaller than the mockingbird, is a uniform slate-gray color with a black cap. Not easily seen is a rusty-red patch of feathers on the underside of the tail’s base, a distinctive mark. The catbird loves the shaded understory layer of the forest and often sings from that cover. The song is softer, more musical with single individual, unrepeated phrases mimicking other birdsongs.
Between my grandmother’s summer kitchen and the woodshed was a large mulberry tree that was laden with fruit each year. (The summer kitchen was a frame building separated from, but connected, to the main house by a short boardwalk. The kitchen wood-burning range was moved there during the summer to keep the heat out of the main house).
I was never a big fan of fresh mulberries, but catbirds and other small birds loved
them. At times their droppings caused considerable grief when the laundry was
hanging out to dry. White shirts seemed a favorite target for the catbird.
The catbird’s nest is well-concealed in dense shrubbery like the mockingbird’s. It
is a deep cup constructed of coarse twigs, lined with grasses, and fine rootlets. It
usually lays four, deep greenish-blue eggs that are unmarked. As a youth I was
expert at crawling into the densest thicket to discover their nest, undeterred by
the threat of chiggers and ticks. I was always careful not to disturb the owners but
kept a mental record of the locations. The catbird is a permanent resident in our
area. It feeds on insects and fruit in the summer and dried fruits and berries in the
winter.
My particular favorite mimic thrush is the Brown Thrasher. The largest of the three cousins and is slim bodied, rich, reddish brown above with a heavily streaked breast, a thoroughly handsome bird. Its habitat is the forest edges and recently cut over woodlands.
It spends considerable time on the ground searching for insects, seeds, and nuts. In the manner of blue jays, it will crack the kernels of larger acorns into smaller beak-sized pieces.
To me it is the shyest of the group and challenging to get good photographs. I was older when I learned to distinguish the Brown Thrasher’s song. The male sings from a favorite treetop perch, usually repeating each borrowed phrase in groups of two, never repeating in groups of 5-6, or more, as is the habit of the mockingbird.
I have never knowingly discovered a nest. They often nest on the ground or low cover under a bush or shrub. A platform is built of sticks and twigs, then lined with plants stems and leaves, and finally, rootlets. The site is most often concealed from above by over-hanging branches. The average clutch size is four bluish-white eggs thickly covered with reddish-brown dots. Unlike his two smaller cousins, the male brown thrasher helps to incubate the eggs as well as feed the young.
Hopefully you can get outside with your loved ones and get a look at all three of our local mimic thrushes and hear their lovely, interesting songs.
This post was for Alice.
Happy Hiking!
Recommended reading:
A Field Guide to the Birds (Eastern), by Roger Tory Peterson
A Field Guide to Birds’ Nests, by Hal H. Harrison
Special thanks to Les Baker
Photos by Les Baker and the author as noted