In short, yes. Two examples to consider. (1). Look at the number of cormorants roosting and feeding on our midland lakes. (2). I have counted upwards of 200 seals on the Raven Point at the mouth of Wexford harbour. Logic dictates that the priority for both these species is a ready supply of food. For cormorants (a sea bird) the midland lakes are obviously a better bet. For the seals, in a desert when short of water head to the oasis. Wexford harbour mouth has a ready supply of migratory salmon/seatrout, bass, flounder, mullet. With the general shortage of fish in the Irish Sea (Cod down 90%), an area of concentration for what stocks remain is the place to set up camp, hence the Raven.
Darwin worked it out and termed it evolution, put simply "survival of the fittest". Over fishing has a lot to answer for.
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