Space Invaders

Another gray morning. On my enclosed porch, my chair in the corner faces east to catch the rays of the rising sun. But the day is starting cloudy once again, with a stiff, cold wind out of the north-northwest.

As I stare out, sipping my coffee, the sky turns black. Thousands of dark birds, all heading norttheast, fill the sky, a veritable river of birds, more and then more still. I think of Audubon's description of the now-extinct passenger pigeon blackening the sky: "The air was literally filled with Pigeons; the light of noon-day was obscured as by an eclipse..."

These birds, however, were common grackles.

You see them in small flocks for most of the year, but in winter these shiny, long-tailed birds mass in flocks of thousands.

Grackle flock, February 2020 (Margo D. Beller)

Why certain types of birds do this is not known. Safety in numbers? A need to keep warm? Easier to find food? All of the above?

In my area of the country, the common grackle predominates. The much larger, aptly named great-tailed grackle is a bird of the southwest. I have never seen one, but I have seen the shore-loving boat-tailed grackles when I've been on one of the New Jersey or Delaware beaches. An easy way to tell the boat-tails from the common grackles is by looking for the smaller females. If she is brown, she's a boat-tail. If she's black, she's a common.

What they all have in common, besides their genus, is they can be pests, especially when they arrive in a cornfield, at a yard or mass along a boardwalk in large numbers. 

Female boat-tailed grackle (RE Berg-Andersson)

I've written before about the sudden arrival of literally a thousand common grackles on my lawn back in 2020, a year where we did not get much snow to keep these birds away. (As opposed to 2021, when we got too much snow.) I am fascinated by these extravagantly large flocks that appear out of nowhere, stay for a while and then leave for the next food source.

Grackles breed in northern New England, a healthy swath of Canada and into the U.S. midwest, according to the Cornell Ornithology Lab's range map. But they are found year-round throughout the eastern U.S., and that's where my New Jersey yard fits in.

These invasions in my yard generally take place in late autumn or early spring, before and after snow  covers the lawn. Grackles mass in fields and eat certain crops like corn, but in my area they can mass in parks and will eat just about anything including garbage or, in my case, bird seed. When I look through my open office shade and see one of these flocks showing up in my vicinity, the first thing I do is rush out to pull in my feeders. 

Once the feeders and I are safely back on the enclosed porch, I watch. The birds stalk the ground poking for worms, or fly into the corners (or my compost pile) where they can turn over leaves and search for insect larvae or other food. There is a loud chatter of "chuk chuk chuk" as dozens, hundreds or even thousands of birds call to family members. Then they fly to the next yard or, if I come outside, rise into the trees, continuing their chorus of "chuk" before flying off in small groups until suddenly the rest of the flock leaves.

Robin (Margo D. Beller)

Sometimes, I see fellow travelers. Robins also poke at the ground and turn over leaves for food and so join the grackle flocks, and then hang around after the bigger birds have left to find what is left over. I have seen grackle flocks include cowbirds, starlings or, rare for my yard, rusty blackbirds (named for a call that sounds like a swinging metal gate needing lubrication).

Starlings are interesting. At this time of year they also mass and you will see them flying and moving like a giant organism in the sky, almost like watching synchronized swimmers in the way they undulate as one. (Do a search for "starlings massing" and watch some of the videos to see what I mean.)  How do these individuals know to do that? I don't know.

What I do know is these invasions are another sign of approaching winter, and just as inevitable.