Date: 4/7/25 1:09 am From: Doctor Science <science.dr...> Subject: [JERSEYBI] Corvus species overlaps in central NJ
Last Wednesday I was sitting on my back deck in northern Hopewell Township (Mercer County), when in the course of 15 minutes I saw & heard *all three* Corvus species: American Crow, Fish Crow, Common Raven. It was a very educational compare & contrast!
But it got me wondering: how do these three species sort out living together these days? I say "these days" because Fish Crows are expanding their range inland, so having so much overlap with AMCR is relatively new. And CORA has only returned to NJ in numbers in recent decades as farming has declined and the tendency of farmers to shoot black birds as varmints has faded.
I know that in my yard and surrounding properties the AMCRs are permanent residents, I hear them most days. Ravens & Fish Crows are occasional visitors, but shouldn't this be nesting season, with birds sticking close to home? It may be these are young, unmated birds, out looking for trouble while the older birds are nesting--it takes Corvus 2-3 years to reach sexual maturity, and may be even longer before they first breed.
So, fellow central Jersey birders, what kind of ecological separation have you been seeing between our three Corvus species? Are they feeding/flying in similar areas, but nesting in different ones? I'm talking especially about parts of the state that aren't close to any large river or the ocean, nor the highlands.
Poking around the scientific literature, there are some indications that CORA prefers rocks, cliffs, buildings, bridges; AMCR prefers evergreens; FICR deciduous trees; but those are statistical preferences, not hard-and-fast rules. As for food, they're all opportunistic omnivores, I don't know how much separation there is around here. Though I haven't seen CORA feeding on roadkill, a common practice for AMCR. It's possible Ravens think roadkill is just too dangerous. I haven't noticed any of them joining vultures at big carrion-eating parties when a deer dies in a field.
