Hi, SD, I hope you are well.  I have looked at the link you provided and as usual with scientific links it only provides the abstract of the paper.  Perhaps you are a member of the society supporting the journal and can access the real paper.  Most cannot and thus the article must be judged on its contents absent journal backup.  Bottom line:  when birds get hungry they eat whatever they can.  Failure of primary premise is that food supply is determined by global warming as opposed to other factors such as human fishing or whatever.  Sorry for the females are paranoid comment if it made you mad at me.  But seriously, the gull story is bad science.  Take care.