My advice is ..if its a seagull or worse a flock of seagulls...land! and just enjoy watching them fly for awhile. They attack! Where I live we have Ravens. They're very smart and soon seem to have the attitude of ...here comes that AH with the drone..we'll sit in the tree and hope he crashes..but occasionally they must have a powwow or something like that and there seem to be thousands. I've seen them circling around at traffic pattern altitude.1000 agl. I have no idea what they're doing ..enjoying thermals? It's just not worth it flying in that situation even though I doubt that you would hit one..they are very evasive.
We also have the California Condor. Ugliest bird you're ever seen but they became extinct in the late 80's and were all captured? and placed in protected areas that are marked on the Sectional. Heaven forbid if you were to hit one. It would probably be the end of drone flying in California.
All kinds of reasons to make us not want to hit birds..neither the drone or the bird would survive it probably and when you think of it..Birds are what made first us dream of flight ..why shouldn't we want to protect them.......