Yes, the "on top of a bush" thing precludes the cat-present theory.
Besides, in this neighborhood, I am yet to see an outdoor cat (there were many at my previous house)...
Raptors I see regularly around the university, but have not seen one around the house. Does not mean that they don't pass by. But what are the odds of this happening in 2 consecutive days?
Both birds appeared intact, though I did not want to examine too close.
The only thing I have used recently is "Sluggo" - in addition to the beer fest, wanted to make sure to get rid of the slugs. Sluggo is supposed to be safe for children, pets and wild life, it just contains some very low % of iron phosphate that makes the slugs sick. But it looks like bird feed. Maybe they got iron poisoning, despite the safety claims?
The second crazy observation is that in close proximity to both locations where I found the birds, there is a large spider web. I have seen one of the spiders and it looks to me like a "regular"/barn spider that should not feast on birds... But maybe I am mistaken on the spider type.
Most feasible seems a disease of some sort, like the West Nile, unfortunately.
I would be happy to supply the bodies for analysis but they don't want them
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