The Big Garden Birdwatch: How Public Surveys Support Biodiversity Net Gain

Every January, hundreds of thousands of nature enthusiasts across the UK come together to participate in the Big Garden Birdwatch, the world’s largest garden wildlife survey. Organised by the Royal Society for the Protection of Birds (RSPB), this initiative invites people to spend an hour counting the birds they see in their gardens, parks, or other green spaces. Over the years, this large-scale citizen science project has provided invaluable data on the state of bird populations in the UK, offering critical insights into biodiversity trends. In this article, we explore the role of public surveys in supporting biodiversity conservation, their alignment with Biodiversity Net Gain (BNG) principles, and the advantages and challenges associated with such initiatives.

The Role of Public Surveys in Conservation

Public surveys like the Big Garden Birdwatch play a crucial role in biodiversity monitoring by collecting large volumes of data that would be otherwise unattainable. They rely on the power of citizen science—the active involvement of non-professionals in scientific research—to gather information on species distribution and abundance.

One of the key contributions of public surveys is their ability to detect population trends over time. For example, data from the Big Garden Birdwatch has highlighted the long-term decline of once-common species such as the house sparrow (Passer domesticus) and the song thrush (Turdus philomelos), prompting targeted conservation efforts (Crick et al., 2002; RSBP, n.d.-a). Conversely, the survey has also recorded increases in species like the goldfinch (Carduelis carduelis), providing a more nuanced understanding of how different species respond to changing environmental conditions (RSBP, n.d.-b).

Public surveys can also enhance habitat conservation efforts by identifying areas of ecological importance. In urban environments, where biodiversity is often overlooked, these surveys highlight the value of gardens, parks, and green corridors as habitats for wildlife.

Advantages of Public Surveys

1. Large-Scale Data Collection: Public surveys engage a vast number of participants, enabling the collection of large datasets across wide geographic areas. This broad participation ensures that data covers a range of habitats, from urban gardens to rural landscapes.?According to Gallagher et al. (2024), the extensive data collected through citizen science also plays a critical role in large-scale biodiversity assessments, such as those for the IUCN Red List, by filling gaps in species distribution and population trends.
2. Cost-Effective Monitoring: Traditional biodiversity monitoring methods are resource-intensive, requiring significant funding and manpower. Public surveys offer a cost-effective alternative by leveraging volunteer effort, reducing the financial burden on conservation organisations while still providing data robust enough for global conservation assessments (Gallagher et al., 2024).
3. Public Engagement and Awareness: Citizen science initiatives like the Big Garden Birdwatch raise public awareness about biodiversity and conservation. Participants often develop a stronger connection to nature and are more likely to engage in pro-environmental behaviours. In fact, citizen science fosters public engagement by connecting individuals with tangible conservation outcomes, which can motivate broader participation in conservation activities (Gallagher et al., 2024).?
4. Baseline Data for Conservation Planning: The data collected through public surveys provides baseline information for conservation planning and policy-making. For instance, the UK’s State of Nature Report incorporates data from citizen science projects to inform national biodiversity strategies (Hayhow et al., 2019).?Similarly, Gallagher et al. (2024) emphasise that integrating citizen science into global conservation frameworks ensures that decisions are informed by comprehensive and up-to-date data, particularly for underrepresented regions and taxa.

Challenges and Limitations of Public Surveys

Despite their many advantages, public surveys also present several challenges:

1. Data Quality and Reliability: Since public surveys involve non-experts, there is a risk of data inaccuracies due to misidentification of species or inconsistent reporting. This issue is highlighted in the paper by Jamieson et al. (2023), which discusses the challenges of maintaining data quality in survey research. The authors emphasize that non-experts may lack the necessary skills to accurately identify species, leading to potential errors in the data collected. To mitigate this, organisations like the RSPB provide detailed identification guides and online resources to help participants accurately record their observations. These resources aim to improve the accuracy and reliability of the data by offering clear instructions and visual aids to assist with species identification.
2. Sampling Bias: Public surveys often suffer from sampling bias, as participants are more likely to be concentrated in urban and suburban areas. This can result in underrepresentation of rural and remote habitats, potentially skewing the results. According to Kelling et al. (2019), citizen science projects like eBird often face challenges related to spatial bias, as volunteers tend to record observations in easily accessible areas, leading to gaps in data from less accessible regions. The authors suggest that collecting additional contextual information about the observation process can help address these biases and improve the scientific value of the data. Furthermore, Amano et al. (2016) discuss the spatial biases in biodiversity data, noting that citizen science projects often have uneven sampling efforts, which can affect the accuracy of species distribution models. They emphasize the need for strategies to mitigate these biases to ensure more representative data collection.
3. Temporal Coverage: Many public surveys are conducted annually or during specific periods, limiting their ability to capture short-term fluctuations in species populations. Continuous or more frequent monitoring could improve the temporal resolution of the data. According to Kelling et al. (2019), the temporal limitations of citizen science data can hinder the ability to detect rapid changes in biodiversity. The authors emphasize that while annual surveys provide valuable long-term trends, they may miss short-term population dynamics and seasonal variations. To address this, they suggest implementing more frequent monitoring protocols and leveraging technology, such as automated recording devices, to enhance the temporal resolution of biodiversity data. Similarly, Amano et al. (2016) discuss the importance of addressing temporal gaps in biodiversity information. They highlight that the availability of scientific data varies greatly over time, and continuous monitoring is crucial for capturing dynamic changes in species populations.

Case Studies: Successful Public Survey Initiatives

1. The Big Garden Birdwatch (UK): Since its inception in 1979, the Big Garden Birdwatch has grown to become the largest wildlife survey in the world. The data collected over four decades has been instrumental in tracking the fortunes of common bird species in the UK and informing conservation strategies. A notable success story is the recovery of the red kite (Milvus milvus), whose population has rebounded due to targeted conservation efforts informed by citizen science data.

2. The Christmas Bird Count (USA): Conducted annually by the National Audubon Society, the Christmas Bird Count is one of the longest-running citizen science initiatives globally. Data from the survey has been used in numerous scientific studies, including analyses of climate change impacts on bird distributions (Niven et al., n.d.).

3. Bumblebee Conservation Trust Surveys (UK): The BeeWalk initiative, organised by the Bumblebee Conservation Trust, engages volunteers in monitoring bumblebee populations across the UK. The data collected has provided critical insights into the status of different bumblebee species and informed habitat restoration efforts.

Public Surveys and Biodiversity Net Gain (BNG)

Biodiversity Net Gain (BNG) aims to ensure that development leaves biodiversity in a better state than before. Public surveys contribute to BNG by providing baseline data on species presence and abundance, enabling planners to assess the potential impact of development projects on local wildlife. Additionally, ongoing monitoring through public participation can help track the effectiveness of BNG measures, ensuring that biodiversity benefits are sustained over time.

For example, data from public bird surveys could be used to identify key areas for habitat enhancement, such as the creation of green roofs, wildlife-friendly gardens, and urban wetlands. By involving local communities in the monitoring process, BNG initiatives can foster greater public support and engagement.

Conclusion

Public surveys like the Big Garden Birdwatch play a vital role in biodiversity conservation by providing large-scale data, raising public awareness, and supporting initiatives like Biodiversity Net Gain. While challenges such as data quality and sampling bias exist, these can be addressed through proper training, resources, and data validation techniques.

As the environmental challenges facing our planet grow more complex, the involvement of the public in biodiversity monitoring will become increasingly important. By harnessing the power of citizen science and GIS technologies, we can build a more comprehensive understanding of species trends and work towards a greener, more biodiverse future.

References:

• Amano, T., Lamming, J. D. L., & Sutherland, W. J. (2016). Spatial gaps in global biodiversity information and the role of citizen science. BioScience, 66(5), 393-400. https://doi.org/10.1093/biosci/biw022
• Crick, H. Q. P., Robinson, R. A., Appleton, G. F., Clark, N. A., & Rickard, A. D. (2002). Investigation into the causes of the decline of Starlings and House Sparrows in Great Britain. BTO Research Report No. 290. British Trust for Ornithology.
• Gallagher, R., Roger, E., Packer, J., Slatyer, C., Rowley, J., Cornwell, W., Ens, E., Legge, S., Simpfendorfer, C., Stephens, R., & Mesaglio, T. (2024). Incorporating citizen science into IUCN Red List assessments. Conservation Biology. https://doi.org/10.1111/cobi.14329
• Hayhow, D. B., Burns, F., Eaton, M. A., Al Fulaij, N., August, T. A., Babey, L., ... & Gregory, R. D. (2019). State of Nature 2019. The State of Nature Partnership..
• Jamieson, K. H., Lupia, A., Amaya, A., Brady, H. E., Bautista, R., Clinton, J. D., ... & Hillygus, D. S. (2023). Protecting the integrity of survey research. PNAS Nexus, 2(3), pgad049. https://doi.org/10.1093/pnasnexus/pgad049
• Kelling, S., Johnston, A., Bonn, A., Fink, D., Ruiz-Gutierrez, V., Bonney, R., ... & Kraemer, R. (2019). Using semistructured surveys to improve citizen science data for monitoring biodiversity. BioScience, 69(3), 170-179. https://doi.org/10.1093/biosci/biz010
• Niven, D. K., Butcher, G. S., & Bancroft, G. T. (n.d.). Northward Shifts in Early Winter Abundance: Christmas Bird Counts and Climate Change. National Audubon Society. Retrieved from https://hogisland.audubon.org/sites/default/files/documents/AB_109_CBC_and_Climate_Change.pdf
• Royal Society for the Protection of Birds. (n.d.-a). Big Garden Birdwatch results. Retrieved from https://www.rspb.org.uk/media-centre/bgbw-results
• Royal Society for the Protection of Birds. (n.d.-b). The Bigger Picture. Retrieved from https://web-cdn.rspb.org.uk/whats-happening/big-garden-birdwatch/the-bigger-picture