LET someone else shout you down and your partner is more likely to cheat on you—at least if you’re a chickadee.
The North American songbirds are largely monogamous and mark their territory by singing. Dan Mennill at Queen’s University in Kingston, Ontario, played recordings of one male chickadee’s song in another’s territory. He found that if he engaged in aggressive song contests by playing the recordings at the same pitch and time as the resident bird’s song, chicks born later to the male’s partner were more likely to be fathered by another bird (Science, vol 296, p 873). Mennill…
