30 August 2022

Northern mockingbirds (Mimus polyglottos) are special because they challenge our assumptions.

• Until recently we thought only male birds sing but female mockingbirds sing too.
• Most birds stop singing in mid-summer and don’t resume until the next breeding season but both sexes of mockingbirds sing in the fall.

It was a wonder in 2014 when, after centuries of ornithologists saying that only male birds sing, Karan Odom at University of Maryland documented singing females. Most of the species live in the tropics but even back then 150 female-singing species were documented in North America.

After this breakthrough female singing became a hot study topic and more species were added to the list. Recent studies delve deeper. Do northern mockingbird females mimic like males? A study published this April found that they do.

Mockingbirds are also unusual because they sing in autumn when other birds are silent. They do it because they change location. Those that nest in the northern end of their range migrate south while others move locally (see animated eBird map). When mockingbirds “reappear” in September they are singing again to claim new territory.

Males and females look alike and they aren’t paired up in winter so we cannot tell which sex is singing. Nevertheless we can hear them. Here are some examples.

28 Sep 2021 in Cincinnati, Ohio:

7 Nov 2019 in Harlingen, TX:

I see mockingbirds in Pittsburgh in the winter. Are they local transplants or from further north? Are they male or female? I dunno.

(photos by Cris Hamilton and from Wikimedia Commons; click on the caption to see the original)