Between- and within-population drivers of haemosporidian prevalence and diversity in American robins (Turdus migratorius)

Avian haemosporidians are a diverse group of parasites that infect birds worldwide and have been a major focus of research for decades. Yet, few studies have identified the drivers of infection at the intraspecific host level. We aimed to study the drivers of prevalence and diversity of haemosporidian parasites infecting a common North American songbird species, the American Robin (Turdus migratorius), which breeds across most of the continent. We found little seasonal variation in haemosporidian prevalence in robins, although we detected a significantly positive relationship between robin breeding latitude and co-infection with different haemosporidian parasite lineages. Additionally, robins infected with Plasmodium had a substantially better body condition than those of uninfected robins, which could be due to migratory culling. We detected 31 haemosporidian lineages among the robins we sampled, of which eight were novel. When matched against known haemosporidian lineages, our results..., , , # Between- and within-population drivers of haemosporidian prevalence and diversity in American robins (*Turdus migratorius*)

Dataset DOI: [10.5061/dryad.mcvdnck8z](10.5061/dryad.mcvdnck8z)

## Description of the data and file structure

Data includes American robin banding data, haemosporidian infection status data, and geographic assignment data using feather hydrogen isotopes.

### Files and variables

#### File: Jahn\_et\_al\_2025\_JAV.csv

**Description:** American robin capture, haemosporidian, and isotopic data

##### Variables

* Band: individual bird ID (categorical)
* Band.Date: date of capture in MM/DD/YYYY format
* year: capture year (numeric)
* month: capture month (numeric)
* day: capture day of the month (numeric)
* Season: derived season from capture date (categorical)
* State: categorical US state of capture (Indiana, Alaska)
* long: longitude of capture site (numeric)
* lat: latitude of capture site (numeric)
* Age: bird age class (after hatch year, hatch year; catego...,