The worldwide variation in avian clutch size across species and space
2008

Global Variation in Bird Clutch Size

Sample size: 5290 publication 10 minutes Evidence: high

Author Information

Author(s): Walter Jetz, Cagan H. Sekercioglu, Katrin Böhning-Gaese

Primary Institution: University of California San Diego

Hypothesis

What factors determine the variation in clutch size among bird species across different environments?

Conclusion

The study found that intrinsic factors like development mode and extrinsic factors like temperature seasonality significantly influence bird clutch size.

Supporting Evidence

  • Clutch sizes vary widely, with more than half of all birds laying 2 or 3 eggs.
  • Precocial species have larger clutches than altricial species.
  • Clutch size increases with temperature seasonality.

Takeaway

Some birds lay more eggs than others, and this study helps us understand why by looking at both the birds' traits and their environments.

Methodology

The study analyzed clutch size data from 5,290 bird species, integrating intrinsic and extrinsic factors in a combined model.

Potential Biases

Potential bias may arise from the exclusion of certain species and reliance on averaged data.

Limitations

The study excluded brood parasites and pelagic species, which may limit the generalizability of the findings.

Participant Demographics

The study included a diverse range of 5,290 landbird species from various geographic regions.

Statistical Information

P-Value

0.001

Statistical Significance

p<0.001

Digital Object Identifier (DOI)

10.1371/journal.pbio.0060303

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