A new study documents the steep decline of a population of endangered southwestern willow flycatchers over 16 years — and the change in the sex ratio that has left the birds’ future hanging on a dwindling number of males.
A new study documents the steep decline of a population of endangered southwestern willow flycatchers over 16 years — and the change in the sex ratio that has left the birds’ future hanging on a dwindling number of males.