Greater Yellowlegs - Shorebirds.

The Greater yellowlegs on the bank of the Pitt River.

A niche is a term used in ecology that describes an organism's function; essentially it is the "job" of the species.  Feeding habits, preditors that consume it, where it lives, and its impact on the environment are all aspects of it.  Shorebirds have a very interesting niche in that they tend to feed in or near shallow water, often within a very narrow range of the shoreline.  The water body can be salty or fresh, moving or still, natural or manmade.  To them, it is where the buffet is located.

Shorebirds that spend time in water often have similar body shapes.  Many of them have noticeably long legs and a long beak.  The theme does not end there though, as long necks and feet together with their other unique body parts all enable them to extract food.  The peculiar part is that often the meal they are persuing is not on the water, in the water, or even on the bottom of the water.  It usually lies beneath the bottom, often residing in mud or sand. 

The long legs allow them to stand in the shallows and not float.  This becomes an important part of the feeding method.  The long feet prevent the birds from sinking into the soft substrate; increased surface area reduces the likelihood of sinking into the mire.  The neck permits the head to get into position to feed, often underwater.  It is the bill that really does the job though.  Each species of shorebird has its own beak and body design, but all of them are built to feed in their particular place in the ecosystem they inhabit; their niche.  (Go to this website to look at and compare a variety of shorebird body and bill shapes).

What can be most effectively describes as a feathered sewing machine will help you to visualize the feeding method often employed.  Pumping up and down like a piston in a cylinder the bird rapidly thrusts its beak into the soft benthos to disturb any tasty morsels hiding there.  Crustaceans, annelids, flatworms, insects, and mollusks are all on the menu.  The bill's action converts the solid substrate into a colloid of liquid/dirt particles allowing the prey to be easily separated from its earthen embrace.  It is especially gratifying to see a whole colony of these birds feeding simultaneously; it's like a heard of sewing machines broke free from a clothing factory.

The particular place the bird feeds is very much dependent upon its structure.  The greater yellowlegs feeds in deeper waters than many of its cousins because of its size.  It will find food a little further away from the water's edge; a place that likely has not been explored.  In our area spotted sandpipers often feed in shallower areas and sanderlings keep to the very edge as their short forms are not conducive to deeper waters.  Niches can be very specific that way.  A few inches this way or that will often define what organism lives or feeds there.

Thanks for reading.   www.ericspix.com   Eric Svendsen