Newly released census numbers show a 2 percent decrease in the African American population of New York City, a drop that echoes across the Northeast, the rust belt, and the West coast. It's a full-blown trend: Blacks are heading South.

This isn't exactly a new development. Since the end of the 1960s, African American populations have been on the rise in southern states. But the 2010 census numbers do present a departure from a longstanding reality in New York state. For the first time since the census began in 1970—and likely, since the Great Migration brought an influx of blacks from an economically-hobbled South in the first half of the 20th century—New York's black population has declined over the course of a decade.

For city-dwellers, hearing the term "black flight" probably rings gentrification alarms. The borough of Brooklyn, especially, has a reputation for younger white populations pushing African American New Yorkers out of historically black neighborhoods. Indeed, census data maps lend some credence to this belief; booming neighborhoods like Williamsburg, Park Slope, and even the edges of Bed-Stuy show signs of whitewash.

Census map showing African American population change in Brooklyn since 2000.

Correlation, however, does not equal causation.

"Gentrification is playing a role, but it's more than just that, right?" said Dante Chinni, a journalist who started the Patchwork Nation project to study demographics throughout the U.S. "If it were just gentrification, they could move out of cities and into suburbs, but it sounds like it's more than that. It's a regional move, out of not only the city, but the entire area."

The migratory trend is interesting because it touches several uncomfortable notes in the American conversation about race: Gentrification and reactionary white guilt; blacks returning to a region that was once extremely hostile to them; an economic squeeze that may disproportionately affect some races more than others, forcing movement. That's why it's tempting to focus on the African American population's migration. It feels like there's a big story about race here.

But according to several sociology and demographic experts, the 2010 census is more about class and money than anything else.

"The places they're leaving are mostly areas of higher unemployment or areas where they think there's going to be less opportunity in the future," said John Logan, a professor of Sociology at Brown University. "It's not to the South, blanket; it's to particular attractive places based on employment prospects."

James Gimpel, a professor of Government at the University of Maryland, agreed. "This is all about employment and job growth," he said. "Labor markets, even in the recession, southern states have been faring better than North, East and Midwest. That's also true of state governments. Black populations are no different than white populations or anyone else. They can see that employment prospects are going to be better in one location than another."

That's not to say this trend is all about jobs, jobs, jobs. Familial considerations are certainly in play, as it's likely that black populations in the North have ties to populations in the South, from where many migrated after the Reconstruction. In that sense, Professor Gimpel said, the South represents a more comfortable move than long-distance transplants usually face.

But according to the census, migrant blacks now tend to move to southern cities with very small African American populations; they're not necessarily joining established communities. When it comes to the bottom line, we might borrow one of Bill Clinton's: It's the economy, stupid. Especially as it pertains to New York.

The Great Migration was precipitated by a southern agriculture industry that suddenly found black labor superfluous around the turn of the 20th century. Advances in technology and sores from the Civil War made the region generally inhospitable socially and economically for blacks. When they moved North, they were following the industrial revolution—the jobs—as much as anything else. Now that manufacturing has been on a steady decline in New York state and the rest of the Northeast, the tide has turned. Jobs are in the South, which is why the total population in the region, not just African Americans, has been growing steadily for some time now, and has been spurred by the recession.

Coupled with the recession has been an explosion of wealth in New York City. In his research, Dante Chinni looked at the median family income in every country in the United States from 1980 to 2010. He found that in the entire country, the county with the largest increase was New York City county—Manhattan. In 30 years, the median income nearly doubled, jumping 85 percent.

Which exposes another trend. The South may be experiencing growth across the board demographically, and New York City may be losing African Americans, but whites continue to come to the big apple. Chinni said that might be a reflection of the wealth explosion in Manhattan: The whites that have come to New York might be taking jobs in finance and real estate, city industries that are still profiting and expanding even in the economic downturn.

Step back from the data, and what emerges is a picture of a city whose middle class is being squeezed out.

"It's harder to be middle class in New York City, probably now more than ever," Chinni said. "Maybe you had a job in the service sector, and you could make it living in New York with that kind of money maybe 10 years ago, 20 years ago, and now it's less possible. So what can you do? Move South to a location where there are jobs and where you can get by on making a little less money than you'd make in New York."

By that estimation, the population shift, both in New York and the rest of the country, runs deeper than race. We might not be a city that's becoming less black so much as we are a city becoming less inviting to the middle class. It just so happens that in the United States, being African American makes it more likely that you'll fall in the lower rungs of the economic ladder. Gentrification, for example, is an economic story that happens to play out often along racial lines.

Chinni said that ultimately, these census numbers may be telling us something about the way people identify themselves, rather than the way we identify people. Migrating to the South, joining communities without established black populations—this isn't about skin, it's about having a job.

"Maybe we're thinking about whether or not you belong in a different way," Chinni said. "Particularly if African Americans are from the North and the head South, you're viewing yourself much more as, 'I'm a middle class person, I want to live in a middle class neighborhood.' Families moving down there may be saying, 'I belong in this neighborhood as much as the next person. It's not about what color I am.' Maybe that's the way they're looking at it."