There is a daytime roost of Black Vultures on the east side of Seneca Creek at 
the mouth- Riley’s Lock. They perch on a large tree and also sometimes on a 
small island in the river just below the tree. There are about 50 vultures many 
juveniles. Their behavior can be quite spectacular rising from the tree and 
island as a group, flying low east downriver. Once after an hour; the group 
returned and circled low over the roost site. Then instead of alighting as I 
expected, they rose in a rotating kettle high into the sky. The kettle then 
drifted northwest rising higher and higher until it vanished. I have been 
watching and sometimes photographing them mid afternoons. Bob Hartman 
saw them in the late morning. 

This behavior is apparently typical. I did a little simple research referring to 
Peter Dunne’s Field Companion Guide, the 1996 Maryland Breeding Bird Atlas 
and a number of Web sites. I found they have communal roosts, forage as a 
group, often late in the afternoon taking advantage of thermals produced by 
rising land temperatures. They forage from great heights. I know, I’ve seen 
them so high that they were almost invisible. According to the references the 
young remain with the adults for a considerable time.

I have an Osprey question. This roost, which must be relatively new, cannot 
be the only day roost for Black Vultures in the area. There must be more than 
50 Black Vulture foraging along this part of the Potomac. Has anyone seen 
others? They must be hard to miss.

Phil Brody