# The Greater the Tilt, the Taller the Nest? The Effect of Solar Array Type on Bird Nest Architecture and Nest Microclimate

## TL;DR

Birds like robins adapt their nest architecture and microclimate when nesting in moving solar arrays compared to fixed ones.

## Contribution

This study reveals how bird nest architecture and thermal conditions vary with solar array type.

## Key findings

- Robins built taller nests with more variable attachment angles in tracking solar arrays.
- Nests in tracking arrays experienced warmer thermal conditions than in fixed arrays.
- Generalist bird species adapt to dynamic solar array environments by modifying nest structures.

## Abstract

The increasing demand for renewable energy has led to widespread installation of photovoltaic (PV) solar arrays, however, their ecological impacts, particularly on bird species, remain poorly understood. This study investigates robin nesting behavior within fixed and tracking solar arrays in Dayton, Ohio, with a focus on species presence, nest architecture modifications, and thermal conditions. We found American robin (
Turdus migratorius
), House finch (
Haemorhous mexicanus
), and House sparrow (
Passer domesticus
) nests across two sites: a tracking array and a fixed array. Results showed that robin nests in the tracking array exhibited significant architectural adaptations, including taller nests and greater variability in attachment angles, likely to enhance stability as panels moved throughout the day. Additionally, nests in tracking arrays experienced warmer thermal conditions than those in fixed arrays. These findings suggest that generalist bird species can adapt to nesting in dynamic, human‐modified environments, modifying their nests to cope with structural movement and thermal changes. The study contributes to understanding bird ecology in solar arrays and provides insights for integrating wildlife considerations into solar energy designs.

Solar energy is increasing at an exponential rate, but little is known about how birds respond to solar arrays, including their nest‐building behaviors. Solar arrays can be tilting that move to face the sun or fixed arrays that do not move. We identified and measured the dimensions of nests built on solar array infrastructure in both a tilting array and a fixed array. We observed only generalist bird nests on the solar arrays, and nests on tilting arrays were taller and hotter than on fixed arrays. Our results suggest that generalist species use solar arrays and that nest architecture is altered due to solar array type. Future studies should determine how arrays affect hatching and fledgling success on photovoltaic arrays.