I thought Blackbirds were territorial (indeed, I've just seen one of our resident males seeing off a robin).
Every year we have a pair nest in the clematis above the patio doors. I don't know if they are the same pair. Anyway, this year, there are two pairs, with two nests about 5 feet apart from each other.
Will they happily co-exist? Is one pair likely to be a returning pair and perhaps the other one of the successful fledglings from last year?
We have two nests. There is ample high energy food and they are not competing for mates so they seem to have no problems with each other. Wouldn't mind betting yours are well provided for also Bm.