Spring Is Coming!
Our latest challenge started last week. Take a few minutes to participate by going outside to take photos, shoot some video, or perhaps do something artistic to illustrate spring’s arrival. I invite you to learn more about springtime birds and participate in the challenge while you’re at it!
Have you ever noticed the changes that occur in your neighborhood when spring approaches? For those who live in areas with long, harsh winters, the changes that accompany spring can be extreme: The snow melts, the breeze carries a distinct scent, the days are longer, and the stars somehow look different. But have you also heard more birds singing? Or have you seen new birds that haven’t been around in months? Have you noticed the birds that were present all winter are suddenly shining brighter and whistling more sweetly? Well, these changes are part of the nature that surrounds you!
The majority of birds change their behavior almost like clockwork in spring. You may ask yourself how, or why, they do this. Simply put, with springtime normally comes abundance, diversity, and better weather. These are all crucial factors when deciding whether to travel to more abundant areas or to stay until conditions improve. It is easiest to start a family when resources are plentiful.
In colder areas, longer days are one of the first indicators that winter is on its last legs. Many birds that breed in the spring and summer start to molt toward the end of winter. With longer days, many birds begin to feather themselves in livelier colors, fly longer trips, or practice impressive songs—both to attract potential mates and to fend off rivals. Today we will talk about the changes in many birds’ plumages around this time of the year. In these coming weeks before spring completely pushes winter out of the way, I will tell you more about these developments.
How many springs have you stood in front of your closet and told yourself, I need to get new clothes! New shoes! Spring is here! Then again, many of us (both birds and humans) don’t only wait for spring. Feathers start deteriorating over time, and most birds molt their feathers completely at the end of summer or beginning of fall. Many species also molt to especially colorful or flashy plumages at the end of winter or beginning of spring, so they can be “well dressed” for courtship and the mating season. But if their feathers aren’t especially worn, how do birds know, or decide, when to molt? We’re pretty certain that they have receptors inside their heads that are so sensitive to light they can detect the almost imperceptible changes in the amount of sunlight per day. When these receptors are engaged long enough for a bird’s brain to ascertain that days are growing longer, hormones flood the bird’s body, and depending on the species cause the bird to molt, reproduce, and/or migrate.
Just as getting a new wardrobe is expensive for us, molting is costly for birds. And they don’t have the convenience of paying with check or credit card; they can’t order new feathers online. Instead, they have to spend a huge amount of energy, proteins, and minerals to grow each feather from scratch. The best-fed and healthiest individuals tend to have the most beautiful plumages, full of bright and exciting colors—important qualities for males trying to impress females with their appearance and courtship displays.
These new feathers don’t grow in a day, of course. It can take weeks, or even months, for a bird to completely replace its plumage. The birds also don’t regrow all their feathers at once. The renewal is gradual, and often occurs section by section along the body. There’s a reason you’ve never seen naked birds flying about. In addition to the fact that feathers keep birds in the air, feathers are the best defense a bird has against its environment, not only for mobility but also to stay warm during colder weather, camouflage, and perhaps a dozen other reasons. Nevertheless, it isn’t unusual to see birds that look a bit rough around the edges, or disheveled, or with colorations that you rarely see in guidebooks—they’re just in the middle of their molt (or down on their luck, in which case you should stop staring)!
When the late winter or early spring molt finishes, the birds that have molted will be wearing their very best. Some birds migrate before or after molting (to do so during a molt would be too tiring); others stay in one place year round, every year. For those birds that do molt in the spring, their next steps are to celebrate the end of winter and find a mate, and then start a new family!
So birds aren’t all that different from us. Go enjoy the outdoors with your loved ones, and see if you can find those differences in your neighborhood birds that tell you spring is coming!
Next week, I’ll tell you about bird migrations in the spring. And if you want to learn more about that challenge I mentioned earlier, visit us at http://www.birds.cornell.edu/celebration/challenge/signs-of-spring-1/signs-of-spring
Until next time!