Brown Pelican

The brown pelican was removed from the endangered species list in 2009. Sometime around 2013 or 2014 (articles written in 2014, probably started in 2013), their main food source, sardines, declined along the west coast of the US, causing their population to decline again. Brown pelicans are an important indicator species for the health of pacific ecosystems.

Source: https://e360.yale.edu/features/brown_pelicans_a_test_case_for_the_endangered_species_act