Sentence:  Their favourite stations are where there is a large extent of sandy shore, interspersed with scalps, or beds of muscles or other shell fish. These are generally uneven in their surface, or are interspersed with pools, which contain, breed, or <WSD>tidely</WSD> receive from the ocean, various molusca and marine animals, furnishing a favourite food to the birds. 
Meaning of the word marked with <WSD> tags:  At each tide; each time the tide comes in; tidally.