Distance within eBird should be the unique distance you covered along a trail, road, or water body, whether by foot, bike, car, kayak, or some even more adventurous means of moving across the landscape. If you submit a single checklist for an out-and-back birding event, only report the one-way distance. Shorter distance checklists are strongly preferred, ideally 1 kilometer or less, but do your best to keep it under 8 kilometers (5 miles). eBird Mobile tracks make this easier than ever.
If you cover the same section of trail out-and-back we encourage you to submit a checklist for the trip in, and another for the trip out. This will provide us with extremely valuable information how detectable different species are under different conditions. However, we understand that many people will not want to submit two lists when walking out and back on the same trail. If you submit a single checklist for an out-and-back birding event, you should only record the distance traveling in one direction, but you should record the total time you spent traveling both out and back on the trail as long as it’s on one checklist. Only record birds on the return trip if you suspect that they are new. Be conservative!
One additional point: we want to collect the complete, accurate track of where you went birding. Please do not stop the track half way through in order to get the one-way distance. It is much better to let the track continue to run to record the full distance (including the doubling back) and then to cut your distance in half.
The most accurate way to report your location is using these new tracking versions of eBird Mobile. If you notice that the track made errors in terms of jumping around off of the route you walked, do your best to reduce the total distance to what you actually covered. If the track is really inaccurate, or if you accidentally hop in the car and drive 20 miles without realizing it, you have the option to delete the track and we recommend you do so in these cases. One of our next developments will be the ability to edit a track to correct for mistakes where you leave the track running for too long—we all have done it!
You can view the track on your device before submission by tapping on the distance and elapsed time on the checklist page, or on the map icon on the Review & Submit page. For the moment, it is not possible to view tracks on your submitted checklists on ebird.org, but rest assured that they’re being stored in the database.
Source: eBird VT Birdwatching