By Kelly Vowels
With spring in full swing, birds can be heard singing throughout Bernheim Forest. My favorite and most interesting bird in song is the Northern Mockingbird (Mimus polyglottos). While there are 16 bird species globally named mockingbird, the Northern Mockingbird is the only one found in the United States. The mockingbird is a mimic. It doesn’t produce its own song, but imitates the songs of other birds, as well as other sounds like frogs and even car horns. There have been times when I’ve gotten excited, thinking I’ve heard the song of an unusual bird, only to discover it’s the clever Northern Mockingbird.
Mockingbirds typically repeat a song two to six times in a roll and switch between different bird songs. One male in Pennsylvania was recorded knowing and using 192 different songs, while another in Indiana had 134 songs. Many males can have nearly 200 songs. The more songs a male has, the older he is, and it is believed that females prefer males with larger repertoires as it indicates age and experience. Both males and females sing, but females usually sing less and use fewer songs. Females sing more when the male is away from the nest and during the fall to establish winter territory. Mockingbirds continue to learn new songs throughout their lives, singing both day and night. The males that sing the most are typically young and unattached, and night singing usually decreases once they pair up. Males have been known to switch their song sets from spring to fall. It is widely believed that their spring songs are intended to attract mates, while their fall songs serve to defend their territory.
Today, northern mockingbirds are very common, but they were once quite rare in the early 1900s. Due to their beautiful and unique singing, they were heavily exploited in the pet trade. Even President Thomas Jefferson kept pet Northern Mockingbirds in his office and sleeping quarters. One of his birds, named Dick, would perch on his shoulder and sing along when Jefferson played the violin. In the 19th century, mockingbirds were illegally taken from their nests, sold, and caged, nearly driving them to extinction. Once the pet trade was banned, their numbers rebounded. Unfortunately, their population has declined over the past few decades for reasons unknown. Despite this decline, their population is still considered stable.
Northern mockingbirds aren’t the only mimics you will find here at Bernheim. The Brown Thrasher and Gray Catbird also mimic other birds, though the Brown Thrasher usually repeats a song twice and the Gray Catbird only once before switching to a new one. You can spot all three species here at Bernheim. Be sure to visit us soon and enjoy the beautiful Northern Mockingbird, along with over 200 other avian species, during peak spring migration.
