Scientists may have gained insight into why some crows try to mate with dead members of their own species.

Scientists may have gained insight into why some crows try to mate with dead members of their own species, a practice known as necrophilia, reports The New York Times.
According to a recently published study, the unusual behavior may have to do with fluctuating hormones and a resulting uncertainty over how to react when confronting a crow cadaver. 
In a blog post, one of the paper's authors, Kaeli Swift, reveals that this research began when she and others were trying to film a crow funeral, a practice they had identified before. 
But instead of mourning the dead, one of the crows swooped in and tried to mount the corpse lying on the ground, notes The Atlantic. 
In the three years since then, Swift studied the behavior and determined, in her words, that "crows sometimes touch, attack, and even copulate with dead crows."
She says she tested 309 individual pairs of crows and "about 4% of crow presentations resulted in attempted copulations."
But she also points out that the sexual acts were usually accompanied by exploratory or aggressive postures, or a combination of both. 
As such, she writes: "what we think happens is that during the breeding season, some birds simply can't mediate a stimulus (the dead crow) that triggers different behaviors, so instead they respond with all of them. This may be because the crow is less experienced, or more aggressive, or has some neurological issue with suppressing inappropriate responses."