Helpers don’t help when it’s hot in a cooperatively breeding bird, the Southern Pied Babbler

In cooperatively breeding Southern Pied Babblers, non-breeding helpers reduce their incubation effort on hot days, but breeders do not. This significant decline in helper contribution to incubation at high temperatures could help to explain why previous research has shown that larger pied babbler groups do not have higher breeding success than smaller groups during hot weather.