Fall is rapidly approaching and a major bird migration is under way. The big push of shorebirds has passed, starting early as it did at the end of July. Neotropical songbirds now stream overhead on calm nights and during the day, raptors ride the northwest winds that help push them toward their southern wintering grounds.

I thought about this exodus as I headed out for my afternoon run but was reminded that not all the birds would be leaving us for the winter. A northern mockingbird, perched in a maple tree just starting to show the first tinges of red, belted out the songs of several different birds as if to prove this point.

Mockingbirds have been expanding their range northward into Canada over the last several years. Although some populations at the northernmost limit of their ranges may migrate, for the most part these birds remain on their breeding grounds year-round.

Mockingbirds hold a special place in my heart, as they are one of the first birds I learned to identify when I got into this hobby. At the time I was living in Jersey City, N.J. Not the best part of the state to be living in, especially since it was sadly lacking in avian diversity – being overrun, as it were, with the invasive European house sparrows, starlings and pigeons.

A few birds did manage to co-exist with these foreigners, though. Two pairs of mockingbirds had staked out territories at either end of the block I lived on. Although it wasn’t a very nice part of the city, there was enough lawn space, trees and shrubs for the birds to utilize for feeding, nesting and singing.

I remember being thrilled late one night as I was awakened at midnight by a mockingbird singing its heart out. Normally, I don’t enjoy having my sleep disturbed, but considering I was often jarred out of slumber by car alarms, police/fire/ambulance sirens, or people screaming at each other, this was a welcome change. It actually made me smile.

I remember, too, the first time I was able to distinguish many of the bird songs the mockingbird mimicked. Doing this was easy, as the mockingbird typically repeats each song three times before going on to the next. I counted house sparrow, northern cardinal, blue jay, starling and house finch; there may have been more that I don’t now recall. This is in no way a true representation of its repertoire, which may contain as many as 150 songs. They can also learn and reproduce mechanical sounds and sounds of nonavian species.

The mockingbird has a distinctive call note, a short, harsh, grating call that I learned to distinguish from similar sounds made by starlings. I was often greeted by this sound as I passed the ornamental plantings in front of my apartment building.

Both male and female mockingbirds sing, and both will sing to establish summer and winter territories. Mated pairs often stay together year-round, but sometimes a female will leave her mate and establish her own winter territory; ornithologists are not sure why she may do so.

Mockingbirds are known to be particularly pugnacious when defending their territories, nests and young, and they will do so against other birds, mammalian predators and people. However, they will only defend winter territories – which contain a food source – from other birds.

Utilization of both insect and fruit food sources enables the mockingbird to live in northern latitudes year-round. It prefers the fruit of holly, cedar and juniper trees, as well as sumac. They will also visit backyard feeding stations.

As I headed out on my run that cool, late summer day, the mockingbird’s song floated on the wind after me. I wondered how many mockingbirds were in the area, as the neighborhood seems to be a hotbed for them. Farther along on my run, I ran into a trio of them as they foraged in the short grass along the path, and I was constantly hearing their call notes and snatches of song.

I’m so glad they’ll be here to keep me company throughout the winter.

BDN bird columnist Chris Corio can be reached at bdnsports@bangordailynews.net