Friday, November 20, 2015

Birds of a feather...

Right now I am doing lots of presentations about birds and their adaptations.  The first thing I do during this presentation is ask the students "How do we know if an animal is a bird?"  This gets a bunch of different responses.

A bird has wings!

I have wings, but I am not a bird...

A bird has a beak!

I have a beak, but I am not a bird...
A bird can fly!

I can fly, but I am not a bird...

Sooner or later, someone will say that a bird has feathers.  I challenge students to come up with an animal that has feathers that is not a bird - the responses are interesting.  Yesterday alone I heard the following answers: a duck (bird), a penguin (bird), an ostrich (bird), a bear (not a bird - does not have feathers).

Every living creature that has feathers a bird.  Let me say that again.  Every single living creature that has feathers is a bird - every single one.

Once we have figured out that a bird is an animal with feathers, we finally start to discuss the different roles that feathers are adapted for.  We usually come up with five different roles.

1)  Feathers give birds the ability to fly. Although not every bird has this ability - no birds would be capable of flight without feathers.

A Herring Gull flying over Lake Superior

An Osprey soaring over Lake Champlain

2)  Feathers keep birds warm.  Fluffy down feathers trap heated air close to a bird's body, allowing them to retain much of their body heat.  In cold conditions, micro-muscles attached to each feather will fluff up the feathers to trap even more air.

This Junco doesn't mind the cold

Snowy Owls don't migrate south to avoid the cold - they come south to find more food.

3) Feathers keep birds (mostly) dry.  The structure of outer contour and flight feathers prevents most water from reaching the fluffy down feathers underneath.  Aquatic birds such as ducks and geese have glands that produce oils.  The birds spread these oils on their feathers through the process of grooming - making themselves even more waterproof.

A Mallard's waterproof feathers keep it warm and dry even on the edge of a frozen river.

A Common Loon dives below the surface after fish.

4)  Feathers help birds stay hidden.  Many birds use their feathers as camouflage.  Sometimes all birds of a particular species will use their feathers as camouflage.  In other species only the females will have dull-colored feathers that help them blend in.

This Barred Owl blends in with the bark of this Eastern Hemlock tree.

Female Red-winged Blackbirds use their dull colors to avoid predators

5)  Birds use their feathers to show off.  In may species, male birds use brightly colored feathers to intimidate rivals and show off to potential mates. 

Male Scarlet Tanagers are shockingly bright red.
A large patch of red and yellow on the shoulder of this Red-Winged Blackbird announces his health to rivals and potential mates.

Can you think of any other roles that a bird's feathers are adapted for?

No comments:

Post a Comment