Bill shape and structure determines ecological niche for water birds.

 

Top:  white pelican, osprey, curlew
Bottom:  flamingo, coot, snowy egret

As someone who works on stuff, I know that "The right tool for the right job" is an important adage.  And although I have used lineman's pliers as hammers and screwdrivers as pry bars, I can do a better job with the right equipment.  In a way, birds have the same predicament and philosophy.  

There are six main ways that water birds obtain food.  They can:

• Catch it with long necks and pointy beaks.  Such are the egrets, herons, and cranes.  A long neck allows lightning strikes, while a sharp beak can be used to both impale and thrash prey.
• Sieve benthic material.  Wide bills with lamellae allow bottom mud and organic material to be strained, pushing out water and tiny solids like sand and silt while keeping small organisms hidden in the debris.  Birds with this ability include flamingos, some ducks like shovelers, and spoonbills.
• Probe the benthos for living organisms.  Birds such as avocets, curlews, and sandpipers can probe beneath the sediment to find food that many other birds may miss.  Many times the bill is curved; it lends some assistance in avoiding obstacles and following natural curves found in tunnels made by prey.  
• Pick up food bits it can see.  Small, generalist bills, such as those found on coots and small sandpipers, allow them to select items easily found on the surface of water or benthos.
• Other birds hunt in groups and use bills either designed to net birds (pelicans) or to grab and hold onto fish, which are then swallowed whole.  Cormorants dive for fish and use their backward-ridged bill to hold onto prey until they surface.
• Then there are birds of prey, whose talons allow the capture of slippery fish and whose beaks can tear them to shreds.  Eagles and Osprey fit in this category.

But it doesn't end there.  The length, sturdiness, curve, and sensory structures of beaks allow each species to find food at different levels, different water depths, and of different sizes, reducing competition and facilitating successful acquisition.  Add to that variations in body size and shape, and it is quite amazing how many birds can come together to fill different niches, obtain food, and not compete directly with one another.

I have been fortunate to photograph hundreds of water birds over my tenure as a wildlife enthusiast.  The more I photograph, study, and blog, the more I learn about the marvels of the animal world.  

Thanks for reading.

Eric Svendsen     www.ericspix.com