I was in Northern California in a restored meadow, very rich with green
grass, dense, thick willows and alders, and I heard for the first time at this
location a Gray Catbird which was an uncommon sound in California in general,
and not only was I hearing Gray Catbird but I was hearing an incredible catbird,
a bird that mimicked to a degree I'd never ever experienced before.
Occasionally you'll hear a mimicked phrase in the middle of a song out of a catbird,
but normally it's just nondescript warbling that's taking place. A very rich
song but mostly you can't identify anything other than catbird
vocalizations. In contrast, this bird was giving really fine imitations of a whole
host of different species.
In order to fully appreciate the ability of a particular mimic of an individual
as it as it mimics, an advanced knowledge of wildlife sounds really helps you
tune in to what this animal is doing. This bird was mimicking a Sora rail,
a beautiful song of a Western Wood-Pewee Wilson Snipe, and even a Pacific tree
frog. Really spectacular.
The theory as to why these mimics imitate other species is that the male
with the greatest repertoire is demonstrating to potential mates, to
females, that he's been around, that he through his extensive repertoire has
survived many breeding seasons.
So the longer you've been around, the more phrases you're able to mimic.