Parental effort in warming young: A neglected component of life history strategies influenced by nest structure, brood size, body mass, and bi-parental care

Parental care behavior has strong fitness consequences and has been widely studied, but variation in the effort that species invest in warming young has been neglected. Here, we investigate the extent and possible causes of variation in brooding, or warming, effort among 90 species of altricial birds on four continents. We measured parental warming effort based on the percentage of time parents spent warming young for the first approximately 6 h of each day over the entire nestling period of each species. Our measure of warming behaviour was based on 62,249.5 hours of video data over 10,770 video days while studying 33,777 nests. We calculated the initial magnitude of effort at the start of the nestling period and the rate that effort declined with the age of the nestlings. Higher initial magnitude and slower rates of decrease reflected higher effort. We found that brooding behavior varied extensively among species. Brooding effort was greater in species in which both parents shared the..., , # Parental effort in warming young: A neglected component of life history strategies influenced by nest structure, brood size, body mass, and bi-parental care

Dataset DOI: 10.5061/dryad.gb5mkkx35

We studied brooding (warming) behavior of parent birds of 90 species in four sites that ranged from South Temperate to Tropical to North Temperate: South Africa, Venezuela, Malaysia, and Arizona, USA. We examined the extent to which brooding behavior varied among species with respect to their nest structure, body mass, whether parents shared the behavior, and the number of young in the nest. We measured brooding behavior as the percentage of time spent on the nest warming young based on video recordings of parents throughout the entire period they had nestlings. We defined brooding behavior based on the magnitude of effort on the days that young hatched (i.e., start of the nestling period) and the slope (rate of change) of the decrease in brooding effort as nestlings grew and slowly developed...,