Today we found 4 otherwise healthy Starling chicks about 3 weeks old dead in one of our Kestrel boxes. There was no sign of predation and they looked as if they all had died in the past day or two. The box was on a pole barn next to a field so it could have been from spraying the field or food given the chicks from the parent that had been poisoned. Many farmers poison their fields against belding squirrels in our area of Klamath Basin Oregon.
After reading the recent article in the Spring newsletter on Agricultural Contaminents on Kestrels by Hawk Mountaing it seemed to fit in with what they are also seeing.
While starlings receive quite a bit of not-altogether-undeserved hate from the kestrel community, we won't pretend we aren't a little saddened to hear of the fate of these birds on an individual level. Unless the weather in your area has been extreme lately or the nestlings were emaciated, we have to concur that some sort of poisoning event could be to blame.
You may wish to contact the Hawk Mountain folks just in case they'd be interested in testing these birds. They can be reached at email@example.com. And certainly let them know if you find any dead kestrels in your area.
We'll keep our fingers crossed for happier results for the kestrels in your area.