As the fall season approaches, birds, mammals and plants have to undergo changes to prepare for the conditions of the new season, winter. We will soon see our deciduous trees sheading their foliage as they transition to a period of dormancy, or rest, and contend with the freezing temperatures that the winter season brings. We see our white-tailed deer changing from their summer brown colors to their winter gray colors; we do not see them adding more hair to survive the cold winter nights, but that occurs. The bucks have been busy growing new antlers to help them manage their upcoming breeding season.
Our birds are also going through a series of changes to prepare for the changing season, but for different reasons. Some birds are adding fat to allow them to fly thousands of miles to their wintering grounds in the tropics while others, such as our permanent residents, enter into rest periods to prepare for their breeding season next spring. However, all birds have to go through periods when they change out their old worn feathers for new ones, a process called “molting.” Managing their feathers is a full time chore for all bird species that allows them to survive, not only cold temperatures but normal day to day living.
A couple of observations this week reminded me that many birds are entering into one of their molting cycles. I saw a scruffy looking Great-tailed Grackle with so many feathers missing in his wings and tail that I was surprised that he could even fly. I have had fun over the years describing the perils the grackles go through during their molting periods. I also observed a soaring Turkey Vulture whose normally sleek wing feathers looked like a histogram of stock market prices – each feather a different length. Molting is a complicated process and is different for many species of birds.
Feathers have many functions for birds and all are important in their survival. Feathers regulate the bird’s body temperature, provide a smooth aero foil for flight, provide camouflage for hiding from predators, and allow them to float on water, just to name a few reasons for their importance. The molting process is a highly coordinated function that allows the bird to carry out their normal daily functions while changing out their feathers. Ducks and other water birds go through an eclipse phase where they shed all their flight feathers at the same time rendering the birds unable to fly for a period of a few weeks.
What we are witnessing now is the transition from bright and colorful breeding plumages to more drab and camouflaged non-breeding plumages. Juvenile birds are losing their downy feathers and going through a transition to adult plumages. I mentioned the grackle and vulture molting that is going on at the present time. All species of birds have different time schedules and to some extent different methods. Factors that influence the molting process include migratory vs. non migratory status, climatic conditions, habitats and lifestyle.
Nature has developed these processes over eons of time and the process will continue to change in the future. Birds that can adapt to changing conditions around them have an increased chance of survival. Birds spend hours a day preening and caring for their feathers, any less attention paid to their feathers could be disastrous to them.
When our clothes get worn and tattered we go to the local department store and buy new ones. Molting is a stressful time for birds and all of us can be thankful that we have an easier time of re-clothing. When you next see a scruffy appearing bird, you might offer a little sympathy for his plight.