Date: 3/25/20 7:37 am From: Nick Bolgiano <nickbolgiano...> Subject: vulture-eagle interactions at Tussey Mt HW
Zoey noted yesterday how turkey vultures frequently give away the presence of eagles. If we don't see the eagle when this happens, it is only because we fail to spot it. We look for vultures as much as for eagles. Turkey vultures are deathly afraid of golden eagles. One time, I saw a golden eagle make a pass at one and get very close, only for the vulture to fold up, drop-shift, and evade.
Zoey, being a true vulture aficionado, was quick to learn how this works, which happens way more in the spring than in the fall. One reason for this is that there are many more vultures around during spring golden eagle migration and the second is that the give-away seems to be more common when eagles are moving slowly, as they commonly do in the spring when thermals are more active. The fall golden eagle migration is concentrated roughly two months after the fall equinox, eagles are much more reliant on ridge updrafts, and tend to move steadily through. The spring golden eagle migration occurs near the spring equinox, the sunlight is much stronger, and eagles are able to use thermals to a much greater extent, making spring migration much more challenging as far as spotting the birds. That is why our vulture help is much appreciated. A flapping vulture often conveys a sense of eagle distance.
Attached is a picture of a vulture party preceding an eagle sighting. Also, two pictures of soaring golden eagles, by far the easiest time to identify and age them. Instant ID is from the long tail and relatively small head and how the trailing edge of the wing pinches in at the body, a tip I learned from Dave Brandes many years ago. Bald eagle wings pinch in only slightly and their head and tails are about equal in length, for they have a longer head and a shorter tail.
Over a spring season, these scenes occur many times.