Are urbanization and brood parasitism associated with differences in telomere lengths in song sparrows?

Urbanization reflects a major form of environmental change impacting wild birds globally. Whereas urban habitats may provide increased availability of water, some food items, and reduced predation levels compared to rural, they can also present novel stressors including increased light at night, ambient noise, and reduced nutrient availability. Urbanization can also alter levels of brood parasitism, with some host species experiencing elevated levels of brood parasitism in urban areas compared to rural areas. Though the demographic and behavioral consequences of urbanization and brood parasitism have received considerable attention, their consequences for cellular-level processes are less understood. Telomeres provide an opportunity to understand the cellular consequences of different environments as they are a well-established metric of biological state that can be associated with residual lifespan, disease risk, and behaviour, and are known to be sensitive to environmental conditions...., , , # Are urbanization and brood parasitism associated with differences in telomere lengths in song sparrows?

**rTLDryad.masterfile.csv**

The data presented here is relative telomere length, and life history data collected from adult and nestling wild song sparrows (Melospiza melodia), and how they relate to urbanization, and brood parasitism by brown-headed cowbirds (Molothrus ater).

## Description of the data and file structure

Code and data for Journal of Avian Biology Submission JAV-03220 

**Variables:**

* plate - qPCR plate number
* Age.day  - Age of nestlings in days since hatch, which is indicated by day zero
* Habitat - the habitat type that the individual was sample, either urban or rural
* SOSP.brood.size – number of song sparrow nestlings in a nest.
* Total.brood.size- Total number of nestlings in a nest, derived from adding number of song sparrows and number of brown headed cowbird nestlings in a given nest.
* rTL - Relative telomere length
* date -  Calendar date the samp...