eBird has just started releasing some really neat animations of the abundances of birds throughout the year. They have been giving some supercomputer processor time to analyze the millions of data points that birders have submitted across the US.
One thing that really jumped out at me when I first saw this animation is how low the densities are in the mid-Atlantic region where I study Grasshopper Sparrows compared to their core range in the Midwest and Great Plains. It is also interesting how they linger the latest in the upper Great Plains, long after they have vacated much of the rest of their range.
It will be fascinating to keep an eye on these models as they fine tune them all the variables that are introduced when collecting data from multiple observers, in many different types of habitat.