Potential drivers of differences in breeding phenology as a component of life history strategies among coexisting species

Breeding phenology can have strong demographic consequences. Yet, the reasons why coexisting animal species differ in breeding phenology have received little attention. We tested selection pressures that underlie life history variation, such as age-specific mortality, diet, and body size to explain the breeding phenology of 16 coexisting songbird species in arid shrubland in South Africa. The average start and end dates for the earliest and latest species differed by 1.5 months, with a gradient among the remaining species. Nest predation risk generally increased through the season, although species differed in seasonal patterns. Species with lower annual adult mortality, greater seasonal increases in nest predation, and greater nest predation rates had earlier start and stop dates, thereby reducing demographic risks. Species with higher adult mortality had larger brood sizes that required more food and they bred later when food was more abundant. Evolved timing of breeding thereby refle..., We studied the breeding birds in the coastal shrubland of Koeberg Nature Reserve, South Africa during 7 breeding seasons: 2000-2004, 2014, and 2016. This site and its habitat were described in a study by Nalwanga et al. (2004). Adult mortality of banded birds was studied from 2001-2007.
Nests were found using parental behaviors, where nest-building activity in particular was readily observed, following Martin & Geupel (1993). Large numbers of nests were monitored each year using long-term protocols to estimate nest predation rates and dates of nest initiation. We located and monitored a total of 6754 nests for the 16 most common species over the seven years (Table 1).
We used the date that the first egg was laid in a nest as the initiation date of a nest. In cases where we found nests after the clutch was complete or had nestlings, we back-dated based on the average clutch size, incubation, and nestling periods. We defined the starting and stopping dates each year as the initiation ..., , # Potential drivers of differences in breeding phenology as a component of life history strategies among coexisting species

## Description of the data and file structure

### dataset final.csv

Species data for the variables tested in the paper.

Variables are as follows:

* spp = Latin scientific name of species
* N = number of nests studied
* first5 = average initiation date for the first 5% of nests for each species
* last5 = average initiation date for the last 5% of nests for each species
* median = median initiation date of all nests for each species
* mean = mean initiation date of all nests for each species
* mort = apparent annual adult mortality probability
* dprslope = the slope of the relationship between daily nest predation rate and ordinal date
* Latedpr = daily predation rate late in the season and based on ordinal date 285 = 12 October, which was the latest average initiation date in which all species were still initiating nests on average
* lmas = log10 of average adu...