Scientists believe that the mass seabird deaths in Peru are a result of starvation due to disrupted fish distribution patterns along Peru and Chile’s coasts.

With the temperature of Peruvian waters being unusually high, fish like anchoveta, which flourish in colder waters, have not multiplied in numbers high enough to sustain the bird population.

“When there is a warming of sea surface temperatures the fish go deeper which means fledging juvenile pelicans, which cannot yet dive, are not able to feed themselves,” marine biologist and former deputy fisheries minister Patricia Majluf, told The Guardian.

Last month, pelicans, boobies, and other seabirds began washing up on Peruvian shores in the thousands. The birds began dying shortly after hundreds if not thousands of dolphins died in the largest number of mass dolphin deaths ever recorded.

Despite the scientists’ finds however, the Strategic Development of Natural Resources’ study of the occurrences has so far ruled out a lack of food as a possible cause of death, as well as bacterial infections contamination by heavy metals or pesticides and bacterial infections like brucellosis and leptospirosis.

Yet to be confirmed is whether the highly infectious virus known as morbillivirus has infected the seabird and marine mammal population of the Peruvian waters.