DOI: 10.5061/dryad.3n5tb2rt7
title: No difference in reproductive investment or success across urban and rural breeding pairs in an urban-adapted songbird

description: Species classified as ‘urban-adapters’ are often assumed to thrive in
 cities because they are commonly found across the urbanization gradient.
 However, urban-living populations of many urban-adapted species have been
 found to have lower reproductive success relative to
 their rural counterparts. The European starling (Sturnus vulgaris) is a
 common urban-adapted species found across most of the globe; while
 starlings have lowered reproductive success in urban areas in their native
 range, less is known about how urbanization impacts reproduction in their
 invasive ranges. We tested for differences in reproductive investment and
 success across urban and rural starling populations in Georgia, which is
 part of their North American invasive range. We found few differences in
 reproductive output for urban versus rural starlings—clutch size, egg
 mass, egg volume, incubation behavior, provisioning rates, brooding
 behavior and nestling wing chord were all similar across starling
 populations from more urban and more rural study sites. While urban birds
 produced a higher number of hatchlings and rural birds produced young in
 higher body condition, neither of these factors influenced reproductive
 success because the number of fledglings produced were similar for urban
 and rural breeding starlings. Overall, European starlings in their
 invasive range performed similarly well in more urban versus more rural
 habitats. Future work should explore whether urbanization affects other
 components of fitness in starlings (e.g., adult survival).
description: # No difference in reproductive investment or success across urban and
 rural breeding pairs in an urban-adapted songbird
 [https://doi.org/10.5061/dryad.3n5tb2rt7](https://doi.org/10.5061/dryad.3n5tb2rt7) ## Description of the data and file structure Reproductive and environmental parameters collected for European starling nesting attempts from nest boxes in metro-atlanta.  ### Files and variables #### File: egg.csv **Description:** Data file for egg size analyses ##### Variables * Nest.ID: Unique ID for nest box * Urbanization Status: dichotomous score based on UrbanizationScore value (urban or rural) * Nest Attempt: Ordinal value for how many nesting attempts the breeding pair have attempted * Egg.ID: Unique ID for each egg * Lay date: Date each egg was laid in nest * Length (mm): continuous variable * Width (mm): continuous variable * Mass (g): continuous variable * Egg Age (days): Age of egg from lay date of egg to present date * Clutch size: Number of eggs total in the nest * n/a values mean observation/measurement not collected #### File: incubation.csv **Description:**  Data file for incubation behavior analyses ##### Variables * Nest.ID: Unique ID for nest box * Attempt: Ordinal value for how many nesting attempts the breeding pair have attempted * Urbanization Status: dichotomous score based on UrbanizationScore value (urban or rural) * Julian date: date of measurement as number of days elapsed since January 1st * Incubation (% of time): Percentage of video length where a bird was inside the nest box #### File: nest.success.csv **Description:**  Data file for clutch, hatchling and fledgling number analyses ##### Variables * Nest.ID: Unique ID for nest box * Nest attempt: Ordinal value for how many nesting attempts the breeding pair have attempted * Urbanization status: dichotomous score based on UrbanizationScore value (urban or rural) * Lay date: Date first egg was laid in nest * Clutch size: Number of eggs total in the nest * Hatchlings: Number of hatchlings total in the nest * Fledglings: Number of hatchlings thought to leave the nest successfully. n/a means not collected/observed #### File: nestling.size.csv **Description:**  Data file for chick size analyses ##### Variables * Nest.ID: Unique ID for nest box * Chick age: number of days elapsed from hatch date to present day * Julian date: date of measurement as number of days elapsed since January 1st * Urbanization Status: dichotomous score based on UrbanizationScore value (urban or rural) * Attempt: Ordinal value for how many nesting attempts the breeding pair have attempted * Mass (g): continuous variable * Tarsus (mm): continuous variable * Wing chord (mm): continuous variable * n/a values mean observation/measurement not collected #### File: provisioning.csv **Description:**  Data file for brooding and provisioning analyses ##### Variables * Nest.ID: Unique ID for nest box * Nest Attempt: Ordinal value for how many nesting attempts the breeding pair have attempted * Urbanization status: dichotomous score based on UrbanizationScore value (urban or rural) * Julian date: date of measurement as number of days elapsed since January 1st * Provisioning (trips per hr): Number of times a bird entered the nest box with a piece of food calculated as a rate per hour * Brooding (% of time): Percentage of video length where a bird was inside the nest box