National Weather Service Radar Captures A ‘Birdburst’
The National Weather Service (NWS) has captured birds, flying insects, and other "clutter" on their radar. Pretty cool, right?
Large large flocks of birds can show up on weather radar screens. The phenomenon is common enough that meteorologists have a name for it: birdburst. Doppler radar equipment can register a big flock of birds as a storm. Because the radar uses a wide beam, it can pick up a flock that covers a large area.
This most often occurs at sunrise, when birds leave their nests all at once. If groups of birds from a large flock leave their nests every few minutes, they may appear on radar as concentric rings, which resemble the appearance of the cool, moist air conditions that can produce thunderstorms. Radar technicians, however, have been trained to recognize the difference between a microburst and a birdburst. [Almanac.com]
The NWS also says some of the traffic could be from migrating monarch butterflies. The green shading that you see below are birds heading to roost for the night.