Friday, October 12, 2012

American Kestrel

Donald Stock 2012                                        
This female American kestrel was spotted frequently hunting in the grassy meadows of the Grange Insurance Audubon Center before she was captured in our mistnet in August. American kestrels are sexually dimorphic, meaning the males and females look different. Males have blue-gray on their wings and a rufous-red tail with one black subterminal band, while females are duller, with brown wings and multiple bars on their tail. We aged this bird as a hatch year using the terminal band on her tail.
Kestrels are the smallest falcon in North American, and are related to the peregrine falcon and merlin, both of which have also been sighted at the Grange Insurance Audubon Center!  Sometimes called sparrow hawks because of their small size, American kestrel’s scientific name, Falco sparverius, means “falcon of the sparrows”. It is very common to see kestrels on a high perch, such as utility wires, tall isolated trees or fence posts, scouting for their prey. The majority of their diet consists of insects (love those grasshoppers!) and small mammals, but urban kestrels have been shown to have a diet consisting primarily of small birds.

Kestrels often bob their heads, which allows them to estimate distance.  Their large eyes sit forward on their head, which allows them to have great depth perception. Their eyes also have a high density of cone receptors, enabling the bird to see detail from great distances! One last awesome fact about their eyesight! They can see in the UV spectrum, which allows them to see the urine trails of the small mammals they are hunting as they hover over a field. COOL!  

Donald Stock 2012                                                                         

American kestrel populations declined in the early and mid-1900s in many parts of North America as a result of a loss in nesting habitat. American kestrels are the only North American falcon or hawk to nest in cavities. They are a secondary cavity nester, which means they do not excavate their own nest, but rather use woodpecker holes, natural cavities, and crevices in rocks. As human population increased, crop fields and urbanized areas replaced suitable nesting habitat. Tree-lined field borders and fencerows were cleared, as were dead standing trees (snags). Luckily, kestrels take readily to nest boxes, and ongoing management practices of placing nest boxes on road signs along highways and in other areas of suitable kestrel habitat are helping their populations to recover.
What you can do:  If you have suitable kestrel habitat on your property, you too can aid this bird species by maintaining natural nesting options such as retained snags, or by providing artificial cavities in the form of nest boxes!

What is bird banding - a brief history.

What is bird banding? The simple answer is modern bird banding is a research technique that requires attaching an individually numbered metal tag around a bird’s leg for identification purposes.  However, the practice of marking birds has been around for centuries, and was definitely not standardized! The earliest record involves Henry IV and his personal peregrine falcons, which he banded with metal tags to mark as his property. In 1595, one was lost in France while hunting and showed up 1350 miles away in Malta just 24 hours later! Due to this recapture, we are able to know not only the fantastic distance the falcon flew, but that it’s speed was an average 56mph! John James Audubon is the first person to have "banded" birds in North America. In 1803, he tied silver cords to the legs of a family of phoebes, and relocated two of them the following year when they returned to his neightborhood. 
However, it wasn't until 1899, when a teacher from Denmark, Hans Mortensen, placed aluminum rings, marked with his address, on the legs of a variety of bird species that the basis for our current system was born.  His goal was to see if any of the bands would be recovered and returned to him. Since that time, bird banding has become a standard, systematic scientific research tool. Today, bird banding is regulated by the United States Geological Survey through the Bird Banding Laboratory (BBL). Birds are safely captured using mistnets, and extracted by trained banders. Bands are made of aluminum, and each has a unique identifying number that allows us to recognize a banded bird as an individual. Tens of millions of birds have been banded, and that information has allowed scientists to answer questions such as; where do birds go when they migrate, how old do they get, how long do they live and are populations  growing or declining?
Aside from the wealth of scientific information generated, banding provides a meaningful way to connect people to wildlife and conservation. Here at Grange Insurance Audubon Center, we conduct spring and fall migration banding to monitor birds using the Scioto Audubon Metroparks as a stopover site. We enlist volunteers, teach school groups and engage visitors and provide an opportunity to marvel at these little creatures that undergo such amazing journeys. So please, stop by, visit, and learn a little too!