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Weekend bias in Citizen Science data reporting: implications for phenology studies
Jason R Courter1, Ron J Johnson, Claire M Stuyck
1Department of Earth and Environmental Science, Taylor University, 236 W. Reade Ave., Upland, IN 46989, USA. jason_courter@taylor.edu
International Journal of Biometeorology
|October 30, 2012
Summary
Citizen science data on bird migration reveals a slight weekend reporting bias, with fewer first arrivals reported on weekdays. This bias has decreased over time, suggesting improvements in data collection for climate change studies.
Area of Science:
- Ecology
- Climate Change Biology
- Ornithology
Background:
- Citizen science networks are crucial for broad-scale wildlife observations, particularly for tracking climate change impacts on species.
- Understanding and addressing potential biases in citizen-reported data is essential for accurate ecological research.
- Weekend reporting bias, where more first migratory arrivals are reported on weekends, is a potential issue in phenological studies.
Purpose of the Study:
- To investigate the presence and extent of weekend reporting bias in citizen science data for five North American migratory bird species.
- To assess whether this bias has changed between historical and recent time periods.
- To evaluate the impact of this bias on mean arrival date calculations.
Main Methods:
- Analysis of citizen science data for five species (Baltimore Oriole, Barn Swallow, Chimney Swift, Purple Martin, Ruby-throated Hummingbird) from historical (1880-1969) and recent (1997-2010) datasets.
- Statistical comparison of first arrival dates reported on weekdays versus weekends.
- Examination of trends in weekend bias over time.
Main Results:
- A higher percentage of first migratory arrivals were reported on weekends for all species studied.
- A small but significant difference in mean arrival dates (approx. 0.5 days) was observed for four of the five species.
- Weekend bias decreased from 33.7% (historical) to 32% (recent), with fewer species exhibiting significant bias in the recent period.
Conclusions:
- Weekend reporting bias exists in citizen science bird phenology data but is relatively small and decreasing over time.
- This bias has a minor impact on mean arrival date calculations.
- Incorporating a 'day of week' variable in phenological models can enhance the robustness of findings related to climate change impacts on bird migration.
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