That record was broken by another bar-tailed godwit last October.
On October 13, 2021, a bar tailed godwit identified as tag no. 234684 flew nonstop for little over 11 days to cover 13,560 kilometers without pausing, eating, or even landing for a brief period.
The bird started from Alaska and flew to Tasmania in Australia.
Usually, these birds fly to New Zealand, but this bird made a surprise change and landed in Tasmania instead.
Why does the bird need to fly non-stop?
The migration path is largely above the sea (Alaska to New Zealand). But bar tailed godwits do not have web feet and other adaptations to land on sea. So, the bird must fly non-stop over large water bodies.
Here is a feature about the bird species.