Weather extremes in the Mediterranean winter are associated with reduced apparent survival and delayed initiation of egg-laying in a migratory raptor

Climate change increases the frequency of extreme weather events, to which migratory raptors are particularly vulnerable. We monitored a population of Eurasian Kestrels (Falco tinnunculus) breeding in nest boxes in western Finland (approx. 63°N, 23°E) and applied a capture–mark–recapture scheme to adults encountered at nests from 1985 to 2013 to examine how environmental conditions affect their apparent survival. We included density data of their primary prey (voles), collected during the early breeding season within the study area, as a predictor of annual survival. We also recorded the initiation dates of egg laying from 1985 to 2018 to test whether variables representing winter weather conditions predict laying phenology, with prey density included as a covariate. We found that both frequent and infrequent winter rain were associated with reduced apparent survival, and that vole abundance in the breeding area was negatively correlated with apparent survival. Additionally, we found th..., Breeding adult kestrels were captured at their nests using swing-door traps. Each individual, identified by a unique leg-ring number, was assigned a capture history by arranging successful capture events (denoted as “1”) and capture occasions during which the individual was not detected (denoted as “0”) into a timeline of 29 digits, with each digit representing a capture occasion (year). Captured individuals were sexed and aged into two classes: second-year (“2”) and after–second-year (“>2”).
Timing of egg laying was estimated either by revisiting nests with incomplete clutches or by back-dating from the hatching date, assuming a two-day laying interval and a 30-day incubation period.
Data on Eurasian Kestrels were accompanied by annual abundance indices of their primary prey (voles of the genera Microtus and Myodes), collected in mid-May within the study area. The number of voles trapped with snap traps during one sampling period was totaled and divided by the number of trap-nights ..., # Data from: Weather extremes in the Mediterranean winter are associated with reduced apparent survival and delayed initiation of egg-laying in a migratory raptor

Dataset DOI: [10.5061/dryad.gqnk98t2m](https://doi.org/10.5061/dryad.gqnk98t2m)

## Description of the data and file structure

Data were collected to estimate apparent survival rate and timing of laying of Eurasian Kestrels in relation to the abundance of main prey (voles) and various weather indicators.

### Files and variables

#### File: Falco_tinnunculus_breeding_attempts.csv

**Description:** Nesting attempts of Eurasian Kestrels recorded in 1985–2018 at Kauhava-Lapua study area located in Western Finland

**Missing values** are indicated by \"NA\"

##### Variables

* id: unique ID no. of the nesting attempt
* year: year during which the nesting attempt occurred
* box: unique ID of the nest-box or natural stick nest in which the nesting attempt occurred
* lon_j: longitudinal WGS 84 coordinates of the nesting attempt with ...,