Forecasting the future? Differential allocation of maternal hormones in function of experimentally manipulated social contexts in blue tits Cyanistes caeruleus

Sociability, i.e. the tendency to interact with other individuals, varies significantly within populations, with some individuals being consistently more sociable than others. This variation may be maintained because more sociable individuals can thrive better in certain conditions, in which social interactions facilitate information exchange or cooperation, but not so if social encounters increase aggressive disputes or infection risk. At the proximate level, apart from genes, mothers transfer non-genetic compounds to their offspring that can influence the development of social skills. In this context, they may adjust their offspring’s sociability to match the social environment they will experience after birth, for example, via prenatal hormones. To test this, we experimentally manipulated the social density as perceived by blue tit females before egg laying. We subsequently measured yolk testosterone concentrations and social interactions among family members post-hatching. Females t..., General methods
The study was carried out in Miraflores de la Sierra, Madrid, central Spain (40° 48′ N, 03° 47′ W) during the spring of 2021. We studied a wild blue tit population breeding in nest-boxes located in a deciduous forest, mainly dominated by Pyrenean oak (Quercus pyrenaica), at an elevation of 1250 m. The experimental manipulation took place from mid-March to the beginning of May, i.e., until most clutches were completed. The study area was divided into four plots, two high-density and two control, which included, respectively, 83 and 87 nest-boxes distributed across a similar-sized area. From mid-March onwards, almost three weeks prior to the laying of the first egg in the population, we exposed blue tit adults daily to either a recording of social stimuli simulating high-social density or to control playback. For the high-social density treatment, we broadcasted vocalizations of male and female blue tits. These included male songs and female calls (excluding alarm calls). ..., , # Data from: Forecasting the future? Differential allocation of maternal hormones in function of experimentally manipulated social contexts in blue tits Cyanistes caeruleus

## Description of the data and file structure

The data is divided into four different files:

* eggData_ForecastingFuture.csv: here is the data related to the analyses of yolk hormones and other variables (including clutch size).
* networkData_ForecastingFuture.csv: here is the data related to the analyses of the network degree.
* nestlingData_ForecastingFuture.csv: here is the data related to the analyses of the begging intensity and body mass.
* parentData_ForecastingFuture.csv: here is the data related with the analyses of the number of feeding events and the time spent in the nest.

You can find a description of the variables below:

* nest: ID of the nestbox.
* treatment: social density manipulation.
* 0: control.
* 1: high density.
* minDistSpk: minimun distance to the closest speaker in meters.
* lDate: ...,