By Alexandria Simpson
Although 2012 has begun, we still have a few months left with the 2011 ABA Bird of the Year: the American Kestrel. One of the few things I enjoy about winter is the return of the American Kestrel to where I live in Santa Anna, Texas. I miss their presence on the utility wires along the country roads surrounding my home the rest of the year. In 2011 I regularly saw three within a mile of my home.
Have you ever wondered how birds got their name? Sometimes it is a good match, like the American Kestrel’s scientific name, Falco sparverius. Falco comes from “falcate,” meaning “hooked beak”. Sparverius means “pertaining to a sparrow.” It is small for a raptor and sometimes hunts sparrows.
Many times the common name of a bird is a misnomer. Until the 1983, American Kestrel was most commonly called Sparrow Hawk. It probably got this from its scientific name. Many people call raptors of any sort “hawks,” kind of like we call facial tissues “Kleenex” or adhesive bandages “Band-Aids.” The other possible explanation for calling this bird a “hawk” is because it was thought to be related to the Eurasian Sparrowhawk. It was renamed American Kestrel in the 6th edition of the American Ornithologists Union Checklist of North American Birds, published in 1983.
Even the official common name is not completely accurate. With the development of DNA technology, appearances can be deceiving. While the American Kestrel is found in the Americas and looks like other kestrels, DNA studies show it is not a true kestrel. Merlins or Aplomado and Peregrine falcons, have been suggested as closer relatives. For the present, however, this bird remains the American Kestrel until further research is done.
Fortunately, American Kestrels are much easier to identify and could only possibly be confused with Merlin. Color and patterns can usually be used to identify the kestrel. American Kestrels are one of the most handsome raptors in the ABA area. In all plumages, the back is rufous with black spots. Females have this same pattern on their wings, but males have blue gray wings. If you were to look at the underside of a male American Kestrel’s wing, you would see with a line of spots along the edge that are translucent. While both sexes have a white tip on their tails and a black band above this, males have a red tail, while females have a black and rufous striped tail. In females, the belly is off-white with reddish streaks. Males have a reddish belly with black spots. The beak is blue-black and the legs, feet, and cere are yellow to yellow-orange.
Like many a football player, the American Kestrel sports a pair of black streaks on each side of its face. Although often called “moustache” and “sideburn,” these marks supposedly absorb sunlight so the bird is not blinded by the sun’s reflection into its eyes. This is a great help to the bird as it hunts. Kestrel’s also have black on the top of their heads which may be like a false pair of eyes, deterring potential predators.
American Kestrels are roughly the size and shape of a Mourning Dove. However, kestrels have larger heads, longer, narrower wings, and square-tipped tails. They are 9-12 inches long and have wingspans of 20-24.5 inches. According to the Warner Nature Center in Minnesota, they weigh about as much as two Snickers bars (3-4 ounces) making them the smallest falcons in North America. As with many raptors, females are generally larger than males.
Kestrels were designed for speed and agility. Their long, narrow wings allow them to maneuver easily. Many times, nature supplies the pattern for man-made things. Some say that the U.S. Air Force used the kestrel’s wing design in its jets to improve maneuverability. Kestrels can fly about forty miles an hour, but during dives, this can increase to sixty miles an hour. Another interesting fact about kestrels is their ability to hover; they are the only North American falcon that frequently does this. Another common kestrel behavior is their habit of bobbing their heads and pumping their tails while perching. Scientists believe that these actions might indicate getting ready for takeoff or attack.
The kestrels’ most common method of hunting is to dive down on their prey, hitting it with great force. They often pursue their prey until they catch it. They will also hover over their prey like a tiny helicopter. Amazingly, these birds will harass larger raptors in flight to attempt to steal their food. I have seen one chase a Red-tailed Hawk. They will also rob nests.
American Kestrels prefer to eat rodents and large insects, but they also eat earthworms, scorpions, reptiles, amphibians, other birds, or bats. One interesting thing I learned about kestrels is that they hunt differently according to season, due to seasonal availability of food sources. In summer, they eat mostly insects, while in winter they consume mainly rodents and birds. Kestrels like smaller animals that bigger raptors do not, and this may help keep pest populations down.
Unlike other raptors that kill their prey with their talons, falcons use the small “tooth” on the tip of their beak to snap their prey’s spinal cord. Sometimes they kill and cache their prey to eat later. They regurgitate indigestible parts as pellets. American Kestrels get moisture from the food they eat and usually don’t drink water.
Because American Kestrels do not need a specific food or special habitat, they are able to live in many places. Anything from deserts to grasslands can be called home. They can live at high altitudes or below sea level. Interestingly, in the winter after separating, males and females choose different habitats to defend territories. Males prefer areas with denser vegetation, while females like more open spaces.
Juveniles and females begin migration earlier than males. This is probably because males take longer to complete their fall molt. American Kestrels tend to migrate along specific flyways, but not all of them migrate. Unlike many other raptors, kestrels rarely use the power of thermals to fly; they just rely on their own wing power.
In North America, American Kestrels are the most common falcon and have the widest range. The All About Birds website (http://www.allaboutbirds.org) states that “land clearing during the eighteenth and nineteenth centuries probably raised American Kestrel numbers substantially.” In North America the American Kestrel is classified as a “Species of Least Concern” by the IUCN. However, in some places, like New England, parts of the Pacific Coast, and Florida, they are declining and listed as threatened. All About Birds lists the following reasons for these declines:
- continued clearing of land
- felling of standing dead trees needed for nest sites
- so-called “clean” farming practices, which remove hedgerows, trees, and brush, which contributes to a loss of prey sources and nesting cavities
- exposure to pesticides and other pollutants, which destroys insects and spiders and can reduce clutch sizes and hatching success.
One of the biggest problems for American Kestrels is lack of good nest sites. If you live in one of the areas where kestrels are listed as threatened and want to help, one great way is to put up nest boxes. Plans for a one-board box can be found at http://www.birdwatching-bliss.com/american-kestrel-nest-box.html.
Although a few kestrels that remain in my area (Texas) year-round, the majority migrate here for winter. From late September to mid-March, I often spot them sitting on utility lines or hovering over pastures, each one with its own special spot. They become almost like a landmark.
American Kestrels are beautiful, unique birds, a perfect choice for ABA’s Bird of the Year. I enjoyed learning more about the Bird of the Year and look forward to finding out what the 2012 bird will be.
If you want to discover more about the 2011 ABA Bird of the Year, try these websites:
About the author: Alexandria Simpson is an avid, fifteen-year-old birder from Santa Anna, Texas. While she wishes she could say she has been birding all of her life, instead she has spent the last four years making up for lost time. She wants to become an ornithologist and someday read scientific papers without falling asleep. Her photography, illustrations, and writings have won awards at local, state, and national levels.