You have probably never thought much about feathers unless you raise chickens and wind up plucking them yourself. Or your duvet is full of down and feathers and you find them all over the place if there is a small hole. But, maybe, like many of us, you wish you had wings and could fly – like Icarus – but not with the same consequences. I wish I had feathers and wings because then I would soar into the sky as high as I could go!
Before I begin, this posting is not the definitive answer to everything about feathers or preening. But I hope to give you a glimpse into the importance of both to Red-tail hawks. Sort of a nutshell version. If you are really interested in feathers and believe me, there is a lot to learn, I have included the name of a good book later in this blog.
Red-tail hawk chicks begin to jump and flap in the nest, according to my observations, approximately 2-3 weeks after they hatch. They are building the muscles in their wings when they flap and flap. Flight feathers not only help birds fly and soar but they are contoured and offer protection from the weather. In the first photo below, there is a snow and ice storm in Ithaca on May 8. Big Red’s feathers are keeping her dry and also protecting the chicks. Look carefully at the one under her beautiful red tail feathers.
Several times this spring, the rain has just been torrential in Ithaca. Again, the feathers kept Big Red, no matter how drenched she looked, dry and in turn, she spreads her wings to keep the chicks dry and warm.
When it is really hot and humid as it is in both Ithaca and Syracuse the last few days, rain can be very welcome to hot hawks. Below is an image from the Syracuse University Hawk cam showing two of their newly fledged red-tails dancing in the rain to cool off. It reminds me of being in India in the late 1980s and 1990s. You would beg for the rains to come to cool off and would run out into the rain ever so thankful!
So remember. Flight feathers are not just for flying but they are also for protection from the weather. The water resistance from the feathers comes from hydrostatic pressure. Hydrostatic pressure is the tension between the structure of the feather versus the pressure of the water. Water droplets bead on the feathers.
Wing feathers are the longest and the most useful for flying. Below is a closeup of one of the chicks with their wing feathers starting to grow. Also notice the tail feathers that are beginning on the chick and the recognizable “red tail” of the Red Tail Hawk on Big Red. The chicks will not get their beautiful red tails until they are in their second year. Tail feathers are like the rudder on a boat. They help the birds manoeuvre. About a month after they have fledged, the chicks should be able to soar into the sky.
Approximately 18% of the weight of a Red-tail Hawk comes from feathers. By the time the chicks are 29-31 days old, their dorsal wings should be 90% feathered. Their legs will begin to feather and they will get the characteristic “pantaloons”. The ear openings should be covered and the upper tail coverts should be well developed. By the time they are 35 days old (about a week from a possible fledging or first flight off the nest), the head will be at least 50% feathered, the dorsal body will be 95% feathered, and the breast should be 90% feathered. Their tail feathers should be five to six bands long, preferably. The more bands the more successful the first flight will be.
At the time these chicks fledge, their wing and tail feathers will be longer than their parents. With their first molt, they will return to normal. Molting is the falling out and gradual replacement of the feathers.
There is a really good book on feathers. It is Feathers: the evolution of a modern miracle by Thor Hansen. There is so much to learn including every part and its function! Apparently humans have the DNA to grow feathers but we don’t have the “switch” to turn it on and off. Feathers are much more efficient than their hair. Hawks also use their feathers like a sharpening tool to keep their beaks in perfect condition.
The simple definition of preening is that it is cleaning and maintaining the feathers. Preening reinforces and conditions the surface of the feathers with gland oils. These gland oils contain vitamin D. When the feathers are exposed to sunlight after preening, the oil works as a protective conditioner. The oil in the glands change composition during the year just like you will, if you live in a cold climate in the winter, change the weight of your oil in your car. Red-tail hawks spend approximately 77% of their time preening.
One of the things that I found most interesting about the feathers is that because they are hollow, some researchers understand that birds can feel the changes in barometric pressure and will know what weather conditions are approaching. They are more likely to know the precise weather approaching than the local weather station. They have to. They live outside in the trees, roost on the ledges of buildings, and depend on millions of years of evolution to give them clues to nature’s mysteries so they can survive.