The study analyzed bird communities in Norway using a model that considers differences in species dynamics. By looking at how species change over time, researchers estimated the turnover rate. They found that accounting for these differences helps better understand how environmental factors affect bird populations. By separating similar areas, they could more accurately detect changes in community structure. The study showed that 75% of variation in bird dynamics is due to species differences. High similarity in bird populations indicates a stable ecosystem, important for monitoring human impacts. The model also improved estimates of environmental randomness, crucial for predicting future changes in bird populations.