Most experienced birders are familiar with eBird. Many of us use it every time we go birding. eBird is among the largest biodiversity-related citizen science projects, with 100 million sightings submitted annually. But how does the Cornell Lab of Ornithology (CLO) use eBird data, and how can we citizen scientists give them high quality data?

CLO states that they archive and freely share the information found in checklists “to power new data-driven approaches to science, conservation and education.” At the same time, they develop tools that make birding more enjoyable. eBird allows birders to manage lists, photos and recordings. It also provides species maps and customized bird alerts.

eBird science allows decision makers, scientists and birders to better understand migration, abundance patterns, range boundaries, and predictions of population trends as analyzed by the CLO. eBird states that their data has contributed to hundreds of conservation decisions and peer-reviewed papers—and thousands of student projects.

The 2025 State of the Birds Report from the North American Bird Conservation Initiative was the first large-scale report to incorporate eBird trends data. The analysis documented large declines in Sonoran and Mojave arid habitat birds, Prairie Pothole ducks, Eastern forest birds—and corn-belt grassland birds, including Bobolinks, which are in decline in Pennsylvania as well. The report allows for scientific prioritization of conservation efforts powered by eBird data.

Separately from that report, eBird data confirm the decline of other Pennsylvania birds, such as Wood Thrushes, Golden-winged Warblers, Ruffed Grouse, Cerulean Warblers, Eastern Meadowlarks, Grasshopper Sparrows, Henslow’s Sparrows, and Short-eared Owls.

Eastern Meadowlark

So how can we give eBird and the CLO the best data with which to work? Below is a list of 6 important ways to submit the best data. The eBird Help Center has an extensive list of many more.

  1. Only Complete Checklists are used for eBird status and trends and many other research projects. Make an effort to submit only Complete Checklists. In other words, don’t leave off your list the birds you found less interesting. All wild birds matter.
  2. A checklist should list from one location only.
  3. If you are birding an “out and back” trail and manually submitting the distance traveled (rather than your having let the app calculate the distance while you were walking), do not count the distance of the “back” part of the trail. The scientists do not want to get an inaccurate view of how far apart the birds were.
  4. Give the best possible, conservative count of large flocks. Do not use an X to denote number counted. Tips on how to estimate the number of birds in a large flock can be found here.
  5. Document sightings with photos, recording, or descriptions— especially for unusual or large numbers of birds.
  6. List all seen and “heard only” birds.

eBird is a wonderful resource for enhancing the experience of birding, and using it well makes it a wonderful resource for conservation efforts too. It completely captures the theme of this year’s World Migratory Bird Day: “Every bird counts, your observations matter”!

If you’re new to eBird and need help getting started, click here.

Kevin Browngoehl, Birding Club of Delaware County Member

Photo credit:

eBird logo used with permission of the Cornell Laboratory of Ornithology.

Meadowlark, by Gary Leavens, licensed under CC BY-SA 2.0