This video from Canada says about itself:
Birds of Quebec: Black-capped Chickadee, White-breasted Nuthatch and Red-breasted Nuthatch
1 February 2018
Scientists have found that hybrid chickadees have marked deficiencies in learning and memory compared to their pure species parents, a possible selective disadvantage. The study is the first to identify deficiencies in learning and memory in a hybrid of any species: here.
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