Do robins kill common grackles?

Question

Robins seem to be guarding our yard, and chasing away any common grackles that land there. Sometimes we find a dead common grackle. We never find a dead robin. The dead common grackles show no obvious signs of violence, other than being dead.

I'm just curious to know how likely it is that the robins might be killing the common grackles.

Or do common grackles ever get killed by bumblebees? If they invade the bumblebees' nest, and get dozens of stings, can that kill them? Would they fly away, and then die from the stings, and fall in the yard?

We have an unknown number of bumblebees, and it's the only kind of flying stinging insect we ever see here. We've never been stung, but they do sometimes seem to try to scare us away, by flying towards us at high speed, as if to attack.

Answer 1

Depending on the area that you are in, this may actually be a matter of some concern. While the robins are only defending their territory due to mating and/or parenting issues, the death of the grackles with no obvious signs of injury may indicate that there is West Nile Virus in the area. You may want to contact your Public Health office and see if this is possible, and if so, what measures need to be taken to have the birds tested.

We have this in our area (Dover, Delaware) and have found dead birds in the gutter which tested positive, which is why I know.

As for the bumblebees, they usually do not act the way you suggest -- however, there IS a bee (carpenter bee) that looks a LOT like a bumble bee that does behave that way. You can search on that and see if maybe that is what you have.

Answer 2

If the robins were killing grackles you'd see signs of violence. While many birds will defend territory, especially against egg- and baby-bird-eating birds, it's usually just to drive them off. Disease is much more likely; if the dead birds were crows or ravens I'd say it's probably West Nile, but grackles are like blackbirds and I'm not sure how they react. I'd contact your county health or agriculture department--and to be safe, protect yourself from mosquitos, get rid of standing water, and don't touch the dead birds with your bare hands.