We've stepped up our operations.
Also, it could of been mail delivery. Think about it, for a squirrel the distance from FW to WL is a lot like me traveling from MS to WDW. When you have relatives living that distance it isn't always easy to get messages to them so they utilize the bus system to assist in this.
Was it an oak tree they came out of or was it the tall pine just across the way? The group in the pine tree have been complained on a lot recently about having the stereo up too loud and just seeing if there is a pattern.