At the Project:
Unless you have takeover attempts in progress it may seem a bit quiet now.  
Most females are spending large amounts of time inside boxes incubating
their precious eggs.  When males are present they perch on or near their box
keeping watch and singing at the occasional intruder.  And when nothing else
appears to be happening they often preen their feathers.  Although this may
seem like a "leisure time activity", it's anything but unimportant.  Caring for
feathers is vital for the health and survival of songbirds, especially swallows,
one of the most aerial groups of birds.











Since swallows perch as they maintain their feathers, the apparent calm of
the incubation period is a time when you might want to bring binoculars so
you can observe feather care close up.












Concepts:
Feathers are truly marvelous things.  Remove one from a nest, take it home
and look at it through a microscope or magnifying glass.  You'll be amazed at
its intricacy.

Why are feathers so important to a bird?  Why must they be cared for?
Feathers:
  • Are a bird's flight surfaces.  They streamline, propel, steer, and balance
    a bird's body for efficient aerodynamic passage through the air.
  • Provide an insulating layer between air and skin, keeping body heat in
    and cold and moisture out.
  • Help identify members of a species to each other through their unique
    colorations and shapes, and their use in species-specific behaviors.
  • Are often used in courtship displays and can indicate an individual's
    health and genetic quality to potential mates.
  • Can function to identify individuals within social groups, helping to
    maintain dominance hierarchies.
  • Can be used in aggressive displays that replace the need for actual
    fighting.












What are feathers made of?
  • Feathers are mostly composed of keratin, a hard protein.
  • Bird beaks and claws are also made of keratin.  Your own hair and
    fingernails are made of a slightly different form of keratin.

Are feathers alive?
  • Although feathers are produced by living cells, full-grown feathers are
    non-living tissue.

How do birds care for their feathers?
You should be able to see your Tree Swallows:
  • Grasp feathers and draw them through their bills one at a time.
  • Straighten and arrange their feathers with their bills.
  • Fluff their feathers up with a shivering shake of their body.
  • Spread each wing out over their raised legs one by one.
  • Stretch their wings simutaneously up and over their heads.

What does all this do for the feathers?
These actions:
  • Help remove dirt and debris.
  • Dislodge ectoparasites.
  • "Zip-up" feather parts that have become separated.
  • Return misaligned feathers to their proper place.
  • Reincorporate insulating layers of air between feathers.

You may have heard that birds have a "preen gland".  What is this?
  • A bird's preen gland or uropygial gland is a pimple-like structure on its
    rump.  It's easiest seen in nestlings, like the seven-day-old below.







  • The preen gland secretes an oil that a bird spreads on feathers as it
    draws them through its bill.
  • You should see swallows reach back and touch their rump with their bill
    to get oil as they preen.  
  • It was once thought the oil helped waterproof feathers, but now it's
    believed the oil acts mainly as a conditioner that prevents feathers
    from becoming brittle and keeps skin supple.

Why do swallows scratch their heads and necks with their feet?
  • They can't reach some feathers with their bill so they use their foot
    instead to transfer preen gland oil to hard to reach spots.











Don't feathers get worn out eventually?
  • Yes they do, in spite of all this care.  This is one reason birds "molt".
  • Molting is the systematic replacement of all or portions of a bird's
    feathers by a new set.  Different songbird species have different
    timing and patterns of molts.  Some birds molt more than once a year.
  • Molting usually occurs when nothing else major is going on in a bird's
    life, for instance, before or after nesting, or before or after migration.
  • Adult Tree Swallows have just one complete molt that starts when
    nestling is almost over and extends gradually over several months into
    the autumn.  (Many other songbirds have a complete molt after nesting
    plus a partial molt before the following nesting season begins).
  • Juvenile Tree Swallows also have a complete molt that starts soon after
    they fledge.
  • Molting birds must spend lots of time preening.  

What happens if a feather is damaged or lost before molting season?
  • If a whole feather is pulled out or lost, a new one will be grown at once.
  • But if a feather is only damaged or partly broken off, it will not be
    replaced until scheduled molt.

Questions for the next Topic:  Hatching.
What do you think newly-hatched young swallows are going to look like?
  • Lots of feathers or few?
  • Eyes open or closed?
  • Able to walk or unable?
  • Will they be able they move at all?
  • Will they be nearly independent or helpless?
  • What do you think the young will need to be able to do at hatching?

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Feather Care
Learn About Birds at Tree Swallow Nest Box Projects