Morphometric variation and deteriorating food availability both explain seasonally declining reproductive success of Dicrurus hottentottus (Hair-crested Drongo)

Seasonally declining reproductive performance in avian populations may be attributed to high-quality individuals breeding earlier than low-quality individuals (the ‘quality hypothesis’), to deteriorating environmental conditions (the ‘date hypothesis’), or both. By comparing the reproductive performance among different perennial pairs, and the same perennial pairs across different years, we tested the influence of timing of breeding on reproductive performance in the Hair-crested Drongos (Dicrurus hottentottus) from 2010 to 2022. Breeding pairs that typically laid earlier relative to the population mean (i.e., early-breeding pairs) exhibited a significantly higher fledging rate compared to breeding pairs that often bred later relative to the population mean (i.e., late-breeding pairs). For a given pair, the fledging rate of early-breeding pairs increased when they bred later com..., We collected all the data from the field. We used the within subject model to test whether the 'individual quality hypothesis' or 'the date hypothesis' could explain the seasonal declining of the breeding performance., , # Morphometric variation and deteriorating food availability both explain seasonally declining reproductive success of Dicrurus hottentottus (Hair-crested Drongo)

[https://doi.org/10.5061/dryad.cjsxksng3](https://doi.org/10.5061/dryad.cjsxksng3)

There were three parts of analyses in this paper. The first part was between and within-subject analysis, which could distinguish the effects of between individuals (quality hypothesis) and within individual effects (date hypothesis) (Perennial_pair.csv).  The second part was to analyze how parents' quality affected laying date and fledging rate. The last part was to analyze the variation of food resource during the breeding season (Feeding_rate.csv and feeding_rate_2022.csv).

## Description of the data and file structure

**Perennial pairs.csv** was the data used for most of the analysis, such as the variation of the fledging rate, within-subject analysis, et al. 

 Empty cells in numeric columns indicate missing values (e.g., data not colle...,