Code and data for: Drought to deluge: Differential impacts of snow on mountain chickadee reproduction across the Sierra Nevada mountains

We use this approach to investigate how reproduction in a montane-adapted songbird, the mountain chickadee (<i>Poecile gambeli</i>), varies across elevations and latitudes in response to drought and deluge snowfall extremes throughout the Sierra Nevada mountain range in North America. Our results reveal that chickadee reproduction in lower and higher elevation populations is often, but not always, differentially impacted by drought and deluge conditions and these relationships vary across latitudes.

Reproductive performance in the northern Sierra Nevada was negatively affected by snow deluge conditions at high elevations, whereas drought conditions reduced reproductive output at low elevations. These relationships changed in the central Sierras where drought conditions negatively impacted both elevations, but deluge conditions improved reproductive performance at both low and high elevations. Reproduction in the southern Sierra Nevada was less affected by spring snow levels, likely due to the lower snow accumulation and earlier snowmelt in this region.

These results emphasize the power of long-term studies to inform and interpret citizen science data in order to better understand how animal responses to environmental extremes vary across geographic scales.</p>