The birds, all adults, had obviously died of starvation--their bodies were extremely emaciated. The article didn't get into what these birds eat, but Gail Mackiernan, the retired Assistant Director (& head of the research program) of U. of Maryland Sea Grant College, posted on BirdChat:
Being a marine biologist, I thought that it was odd that the newspaper article did not really speak to the issue of commercial over-fishing of launce (sand-eel), capelin and other forage fish in the North Sea and No. Atlantic. We have a similar issue in the USA, with overfishing of menhaden leading to a cascade of problems for predatory fish and birds, and there are other examples where commercial fishing is affecting seabirds, marine mammals and fish.
Ecosystem effects are usually not considered when fish quotas are set, even though in some cases the trophic levels affected (such as predatory fish species) are far more valauble commercially that the industrial uses to which the forage fish are put. No logic, no cause-and-effect, no clear thinking at all...