Relative breeding timing and reproductive success of a resident montane bird species

The phenological match-mismatch hypothesis predicts that animals that better synchronize critical life history events with the peak availability of their primary food source should have higher fitness. If phenological match-mismatch determines breeding success, most individuals in a population may be expected to breed simultaneously within a given year because selection has favored mechanisms that allow for the tracking of optimal food abundance. Therefore, individuals that breed too early or too late relative to the bulk of the population (“peak” of breeding) should experience decreased fitness. Using 11 years of data, we investigated the effect of relative breeding timing on breeding success in resident mountain chickadees (Poecile gambeli) across two elevations in the Sierra Nevada mountains, USA. Chickadees that bred during the peak of nesting did not have the highest breeding success; instead, birds that bred earliest performed best at high elevation, while at low elevation early a..., , , # Relative breeding timing and reproductive success of a resident montane bird species

Publication: Royal Society Open Science

File preparation date: 16 January 2024

Authors: Lauren E. Whitenack, Carrie L. Branch, Benjamin R. Sonnenberg, Angela M. Pitera, Joseph F. Welklin, Virginia K. Heinen, Lauren M. Benedict, Vladimir V. Pravosudov

Contact Lauren Whitenack at with questions

## Summary of data and code

This paper investigated the relationships between relative breeding timing and breeding success of mountain chickadees. The script includes code for all analyses and figures. The data used include reproductive data from high and low elevation sites and ages of individually-marked birds.

## Data file: mochlow\.csv

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Summary: 11 years of breeding data from low elevation mountain chickadees at Sagehen Experimental Forest, CA, USA.
Each row contains data from a single nest associated with one season.
Column descriptions:
YEAR - Field season year
SEASON - Winter season preced...