Ecomare

The various wader species each have different shapes and length of beaks, which determines the kind of food the bird eats. Curlews, oystercatchers and knots all eat gapers. The long beaks of the curlew can reach gapers buried as deep as 14 centimeters in the bottom. Oystercatchers don't penetrate any deeper than 8 centimeters, while the beak of a knot cannot reach further than 3 centimeters.
Waders look for prey by feel as well as sight. Many benthic animals leave tracks, which birds can see. They follow the track and find their prey. This is when a sensitive sense of feel and taste located at the tip of the bill comes in handy. The tracked worms and shellfish are caught in such a manner that they are dug up undamaged. Plovers catch their prey exclusively by sight. Their beaks are only good for surface picking. Their eyes are so sharp, they can even find food at night by the light of the moon.
Not only do the different species have different kinds of beaks, the various breeding populations within a species show variations. A Dutch biologist discovered that knots which spend the autumn and winter in the Wadden Sea have shorter beaks than those that spend the winter in Mauritania. The Wadden Sea is sandy, which wears out the beak faster than birds that forage in the muddy bottom in Mauritania.

Not only do waders adapt their beak based upon their prey, they are also capable of adapting their weight and pectoral muscles (the ones they used to take flight) in order to escape predator birds. Dutch bird researcher Piet van den Hout discovered this while also studying knots. The birds that are under pressure for predation weigh less and have relatively large pectoral muscles in comparison to knots that are under less pressure. In order to confirm his assumptions, he also tested turnstones.
Turnstones have a different method to escape predators. Knots forage in large groups. When a predator approaches, they take to the air in a tight ball together and fly in a rapid and nimble dance to avoid their enemy. They loose weight and increase the relation between weight and pectoral muscle. If they are too heavy, they will be less nimble and will not be able to keep up with the group. Turnstones forage in solitude and first try to hide by lying low to the ground, hoping their plumage camouflages them. If they still need to take flight, they must accelerate very quickly into the air. Good pectoral muscles are essential and they form in a very short time. In their case, nimbleness is less important than acceleration; body weight stays the same but the pectoral muscles grow, where once again the relation between the two increases. Van den Hout presumes that many waders undergo similar adaptations.