March 15, 2018

Northern Mockingbird Songs

The mockingbird is an exceptional mimic of the vocalization of other birds, but does it have its own song? 

Northern Mockingbird wing flash by Charlesjsharp via Wikimedia Commons

Walking to pick up my older child from school, I typically pass a very small greenspace that's home to peach, pine, and holly trees. The approximate area of the greenspace is 607.55 square feet. The typical birds you'll find in this micro-greenspace are House Sparrows and pigeons. Over the past two weeks, I've noticed a Northern Mockingbird in the holly tree. And yesterday, it was there. I heard it before I saw it. It was singing a chorus of other birds' songs, loudly. I slowly approached the patch and peered into the holly. I observed and listened to the bird for about three minutes. The video recording is below. It was fascinating to hear the diversity of songs and the volume of the singing. The Northern Mockingbird is described as a medium-sized songbird but this one looked rather small tucked into the dense branches of the holly.



When I told my son about the encounter he asked if mockingbirds create original songs or do they only mimic the songs of other birds. I told him I did not know the answer but would research his question. Lucky for me, Bay Nature and All About Birds have written about mockingbird songs. Bay Nature published an article on mockingbird songs. While other songbirds either are born knowing songs or are taught songs by adult birds,* a mockingbird's "repertoire" of songs is learned and memorized from its surroundings, and is not limited to other bird vocalizations. A mockingbird's song repertoire can include non-bird sounds such as car alarms.

A song is a string of phrases in which "each phrase is repeated 2-6 times before shifting to a new sound". Each year, a male mockingbird repeats "35 to 63 percent of his previously heard song types".  In addition it continues to expand its repertoire with new songs. It is estimated that a mockingbird can learn up to 200 songs in its lifetime. For this behavior, mockingbirds are classified as open-ended learners. A song is only one type of bird vocalization or sound. Birds also produce calls. Songs tend to be melodic and long and are typically used for courtship or relationship building while calls are less melodic and shorter and used to defend territory and signal danger.

Here are some additional facts you might like to know about the Northern Mockingbird.
  • Latin name: Mimus polyglottos
  • Habitat: common in urbanized areas and in "brushy fields"
  • Food: omnivorous; forages for fruit (fall and winter) and insects (summer) in shrubby vegetation and on the ground
  • Nest: female chooses among several nests built my male; 2-6 eggs/clutch and 2-3 broods
  • Juvenile: distinguished by spotted breast and absence of dark eyeline
I've read in a few places that the Northern Mockingbird often perches in a highly visible location but this has not been my experience. The mockingbird is one of the winter birds of Washington Square Park, and there I've observed mockingbirds there in densely branched vegetation such as hollies. The mockingbirds I am seeing are behaving more like thrashers (both are in the Mimidae family). In speaking with a more experienced birder, I learned that mockingbirds are more conspicuous during the breeding season. The Northern Mockingbird I am writing about was engaged in singing as we transition to spring. I will assume it's a male advertising its availability. I will look for signs of nest building, and hope it finds a mate and raises offspring nearby.


* Did you know that both male and female mockingbirds sing? Until recently, only male birds were thought to sing, but current research has shown that female songbirds sing, too. However, female birds might limit their singing when on the nest to reduce the risk of predation. I hope to write a follow-up post with links to bird sounds research.

2 comments:

  1. What a wonderful post! We don't have Mockingbirds in Seattle, but one of my fondest memories of a mockingbird's song was after the death of my grandmother. My sister and father went down to LA to clear out Grandma's house. She lived in a rambler along a ravine at the end of a dead end, but kept all her shutters closed during her final years. We three opened all the shutters and threw open the windows (it was in the triple digits during our stay). Birdsong flooded in all day, and especially at dawn when that mockingbird sang its heart out. My grandmother painted birds, but toward the end of her life she closed her experience to the outside, and didnt let nature in. I was glad to be able to experience that again for her, in her house, before we sold it.

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    Replies
    1. Local EcologistMarch 19, 2018

      Thank you for sharing your bird tale with me, Bryony, and one so special. I really appreciate your engagement with the blog.
      - Georgia

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