After the vulture attacked the ducks yesterday, several people commented that vultures normally only go after carrion, so I did a little Internet research. It turns out that there are two types of vultures in North America, the black vulture and the turkey vulture. The turkey vulture apparently only is equipped to eat carrion, but the black vulture has been known to eat live prey, including other birds. According to a USDA National Wildlife Research Center publication, it can be a danger to livestock, especially newborn animals.
The information I found on line also said that black vultures don't have a strong sense of smell, and sometimes rely on turkey vultures to identify carrion for them. They also sometimes urinate or defecate on their own legs to cool themselves down. Charming.
On the other hand, they also are said to mate for life, and have a strong social network.
Yesterday the vulture hovered overhead for a while, apparently trying to lull us (and perhaps the ducks) into a false sense of security. While he (she?) was doing that, a blue heron flew by, apparently heading for the pond. It changed course when it saw the vulture. Why? Are they rivals? Would it fear the vulture?
The picture below has the vulture above and the heron below.
Hopefully the ducks were just a target of opportunity, but they are easy prey. At our other house, we tried to stock the pond with female ducks, but they were just too small, and we lost two of the three to hawks.
The third one had...mental stability issues, and the last we saw of her, she was waddling down our street quacking madly. I think the male ducks who were already at the pond when we moved there were happy to see her go, as they had been exerting strenuous efforts to help her adapt and it just wasn't happening. Poor duck.