GET TO KNOW: Belted Kingfishers
Stroll along the water’s edge and enter the realm of the belted kingfisher. If you are fortunate, you may see this proud king with his ragged feather crown.
FUN FACT: Biomimicry is the science of solving human engineering problems by copying nature. During the 1990’s, Kingfishers (specifically kingfisher beaks) served as the model for a complete redesign of Japanese bullet trains. These extraordinarily fast trains created very loud “tunnel booms” when exiting long tunnels. The booms disturbed wildlife, damaged structures, and angered citizens. (Tunnel booms are created by severe air disturbance and sound similar to sonic booms.) After a bird-watching scientist noticed kingfishers diving without a splash, he envisioned a correlation to trains moving through tunnels. The trains were redesigned to match the shape of a kingfisher bill, and the booms went away.
He surveys his domain from a favorite branch – his streamside throne. Occasionally, he hurtles headfirst and fearlessly into the river to catch his dinner. And if he sees you, he will call out with screams and bursts of rapid, staccato notes to warn you – the intruder – to leave.
The belted kingfisher is a rugged and sturdy bird about 12.5 inches long. It has a heavy bill that serves as a deadly fishing spear and is a fearsome predator that sits near the top of the watershed food chain. In most bird species, males are more colorful than females, but belted kingfishers offer an exception. The female is a bit bigger and more colorful than her king. (This is known reverse sexual dimorphism.) While the king is attired in feathers of only slate blue and white, his lady displays an additional rust colored patch across her abdomen.
Numerous species of kingfishers are common throughout the world, however belted kingfishers are the only ones found in Michigan. Belted kingfishers are widespread across most of the North American continent, and breeding pairs may be found as far north as Alaska during summer months. Since kingfishers hunt and live by water, they migrate as needed whenever the waters freeze.
HABITAT & LIFE CYCLE
As their name implies, kingfishers primarily eat fish, with a few crustaceans, reptiles, and aquatic insects for variety. Like most birds of prey, belted kingfishers have excellent eyesight and color vision. Their eyes are strongly adapted for seeing through water and correctly judging the depth of passing fish. Because kingfishers hunt by sight, they require clear water to spot prey from above.
Like most urban rivers, the Rouge River is very “flashy,” meaning that it rises and falls rapidly (in a flash) in response to rain. In urban areas, abundant paved surfaces quickly move rainfall off the land and into available rivers or lakes. While this may keep our basements from flooding, the large fluctuations erode riverbanks and send the sediment and polluted runoff into the river, making it very murky. Construction projects also often send large amounts of sediment to the river. When the river gets cloudy, kingfishers have a difficult time sighting potential prey. Fortunately, these birds have adapted to such conditions and are known to eat small mammals and even berries when necessary. FOTR works with homeowners, municipalities and other property owners to divert rainfall into rain barrels, bioswales and rain gardens where it can be filtered and infiltrate rather than sending it unfiltered into our streams. Doing so will help to improve water clarity for these birds.
Like a true king, male kingfishers bestow gifts upon their ladies. Courtship includes offerings of fresh fish which the king presents to his intended mate. Lady kingfishers are a bit aloof and typically refuse multiple offerings before selecting a mate for the season. Eventually, the female accepts (eats) a gift as her consent to the union. The newly formed pair then begins construction of an elaborate fortress for their expected offspring.
Belted kingfishers build unusual nests by burrowing far into muddy ridges. They prefer waterfront sites with nearby branches for perching but will move inland if an acceptable waterfront location is not found. These hardworking birds have fused toes that serve as shovels, and partners work together to scoop out the tunnel. Burrows run slightly uphill (to guard against flooding) and reach an average depth of four to six feet. After mating, five to eight eggs are laid in a chamber at the terminal end of the tunnel.
Both parents care for the nest and new hatchlings. All parental duties are split, but females carry out most of the incubating and guarding while males deliver food. Since few animals are able to successfully raid the deeply hidden nests, the young stay safe and snug. Unfortunately, some studies indicate that adult belted kingfishers may abandon nests when frightened by excessive human activity and noise. Once a nest is abandoned, the offspring are doomed to perish. This sad situation is considered to be a significant factor in kingfisher mortality.
Fledglings fly at about 23 days and mature within one year. Both parents are actively involved in teaching fledglings to fly and hunt. For a wonderful, (12 minute) video of belted kingfisher courtship and parenting, watch this short video by Tim Torell of the Nature Conservancy.
At this time, belted kingfishers remain common across North America. The largest threats to the species are from riverbank development and excessive human activity. Since these birds require steep, exposed banks for nesting, even careful river restoration projects may have unintended consequences. One such project took place at Kingfisher Bluff in Dearborn. (at Henry Ford Community College). This site had a steep bank of exposed dirt that was favorite nesting site. However, the site also experienced excessive soil erosion. The restoration project regraded the riverbank and planted native trees and grasses. Artificial nesting tubes were installed in the new bank to encourage kingfishers to nest. Unfortunately, the birds have not yet returned. This situation demonstrates some of the difficulties involved in managing human impact on nature.
FOTR works regularly within the watershed to promote and maintain best practices for watershed protection. Volunteer with FOTR to get involved!
MAIN PHOTO CREDITS: Left – Male belted kingfisher (Megaceryle alcyon) – photo: Henry CC-BY-2.0
Right – Female belted kingfisher – photo: Kevin Murphy – images were cropped