Species abundance in North American birds can change over time, but these changes don't show the same spatial patterns as abundance itself. Researchers looked at data from bird surveys to see how yearly changes in bird numbers were spread out across different areas. They found that while bird abundance was more similar in nearby areas, changes in abundance didn't follow the same pattern. Resident birds had more structured abundance patterns than migratory birds, but both groups showed similar patterns in changes in abundance. The distance from the center of a species' distribution didn't seem to affect how bird numbers changed over time. This study helps us understand how bird populations fluctuate and could be important for conservation efforts.