Fallout?

Just after midnight on Wed., April 10th, a large area of heavy rain swept through upstate New York, heading east into New England. Weather radar showed not only the precipitation, but migrating birds flying as well. In fact, a widespread movement of birds was evident on radar across the eastern half of the United States, from Texas north to Illinois, and eastward to the coast from Florida to New England (Figure 1.)

Figure 1

The light blue rings with medium blue centers show birds aloft around the various radar sites. The darker blues, greens, and yellows indicate precipitation. Looking more closely at the National Weather Service radar display from Albany (the radar site is actually located in Berne), the large area of heavy precipitation can be seen just to the north and west of the Capital District (Figure 2.)  Albany is located at the center of the display.

 Figure 2

The light and medium blue colors are migrant birds, and they are encountering the edge of the precipitation where green is displayed. When migrants find themselves in this situation, they look for a place to land immediately; it is often referred to as a "fallout," as the birds get stopped in their tracks and "hit the deck." The following morning, and perhaps for a day or two afterwards if poor weather conditions persist, can be a good time to look for these birds. 

On Wednesday morning, I found a pair of Horned Grebes in the Mohawk River in Latham. On Thursday morning, there was a Caspian Tern at Collins Lake in Scotia. This morning (Friday) there were three Bonaparte's Gulls at Collins Lake. All three of these species are infrequently seen in our area, but this is the correct time of the spring to see them, as they make their way back towards their breeding areas from the coast. Did the "fallout" conditions help to produce them? 

    Caspian Tern at Collins Lake, Scotia, NY

Bonaparte's Gulls at Collins Lake, Scotia, NY

(Image courtesy of Jeff Nadler, http://www.jnphoto.net/)

What's Next:

Apr. 12th- 18th

Yellow-rumped Warblers will begin to show up this week across the region; they have an unusually long migration "window" that peaks at the end of April-early May. They will be joined by the Blue-headed Vireo, and the diminutive Blue-gray Gnatcatcher by the end of the period.

Marsh Wren, Sora, and American Bittern will return to the marshes and wetlands that they favor this week.

Bonaparte's Gulls are on the move from the coast to their inland breeding areas, look for them at stopovers where gulls typically congregate to rest. Great Egret is occasionally seen in early to mid-April in our area, look for them in shallow waterways and ponds. 

Vesper Sparrow can often be overlooked when it arrives due to the presence of numerous Song and other sparrow species that show up simultaneously. Look for them in short grass areas. They have a distinctive eye ring, and white outer tail feathers that can be observed while they are in flight.

Capital District Bird-Finding Calendar is here

 

TW