Adult Lesser Black-backed Gull with all tail feathers missing. Anza, Morocco, 5 January 2017.
Its mobility did not seem to be affected much as it could be seen flying around quite easily while landing also did not seem to be much of a problem.
Various theories for the cause of this exist, including that of ‘fright-moult’ (for lack of a better term), where all feathers are shed in an attempt to flee from a predator.
Note also the ongoing primary moult (not related to the missing tail feathers but it’s quite late for an adult to still be moulting the primaries at this time of year. More about that in another post though).