Complex sentence: The Wick of Gossabrough attracts many birds, of note here in particular are the great black-backed gulls, and herrings, although in the first decade of the 20th century it was documented that herring populations had declined.
Split into simpler sentences: The Wick of Gossabrough attracts many birds, of note here in particular are the great black-backed gulls. In the first decade of the 20th century it was documented that herring populations had declined.