Driving down a rural backroad on a crisp winter morning, a movement catches my eye. A corncrib, filled to the brim, appears alive with movement. Upon closer inspection, scads of chunky birds, a mixture of greys, browns and whites, cling to the outside of the structure. They peck at the corn cobs, filling their crops with golden kernels. Thieves! Suddenly something alarms them, and the entire flock takes flight, their wings emitting a loud clapping sound that serves as a warning to the group. Their aeronautics take them in a powerful sweep around the farm several times, some individuals pausing to glide while holding their wings in a pronounced V-shape. Finally, they return and alight atop the crib, eventually clinging, once again, to the outside to continue their gorging. To say that rock pigeons are a bane for farmers is certainly an understatement.
Rock pigeons
Rock pigeons (Columba livia) are native to northern Africa, Europe and southwestern Asia. They were introduced to North America in 1606 at Port Royal, Nova Scotia. Also referred to as rock doves or common pigeons, they are pudgy birds, measuring up to 14 inches in length with wingspans of over 2 feet. Striking golden irises punctuate their absurdly tiny heads, along with a fleshy white patch above their noses, known as a cere, which surrounds their nostrils. Their short legs are a garish red. Pure wild strains of the rock pigeon are bluish-gray with two distinct black bands on their wings and a black band around the tip of their tail. Iridescent pink and green feathers highlight their necks and throats. Males and females appear nearly identical.
Rock pigeons have been domesticated for centuries resulting in numerous breeds, sizes, colors, patterns and types. They have also been trained to accomplish important missions as carrier and homing pigeons. Escaped domestic pigeons have greatly altered the pure strains of rock pigeons and have increased the populations of feral pigeons worldwide. In fact, one would have to look long and hard these days to find a flock of unblemished rock pigeons.
Rock pigeons benefit greatly from humans without giving much in return — a term known as commensalism. Human habitations such as urban high-rises or agricultural barns and silos mimic their natural nesting habitats on cliff structures. These areas not only provide plenty of habitat but also access to human food, resulting in a thriving breeding population.
Reproduction
Pigeons can raise their young at any time of the year, due to their ability to produce crop milk or pigeon milk. This milky substance, high in protein and fat, is secreted from the lining of the adults’ crops and regurgitated to the youngsters during their first week of life.
When nesting, the male careful selects a site, often under an overhang or in a sheltered nook or cranny and emits soft cooing calls to attract a mate. He then brings the female sticks, stems and straw, which she weaves into a feeble platform. One to three white eggs are incubated for 18 days, the nestlings, known as squabs, fledging in a month. Amazingly, pigeons will nest up to six times a year, a testament to their successful dependence on human habitation. The same nest is utilized for each successive nesting, and because the parents don’t dispose of the chicks’ fecal sacs, the putrid nests grow into sturdy excrement mounds resembling pots.
Predators
Although the success story of this non-native, feral group of birds is overwhelming, there are a host of predators that are more than happy to dine on them. Perhaps the largest group with a taste for pigeon are the raptors. Red-tailed hawks, American kestrels, great-horned owls and screech owls all depend on rock pigeons for a meal. Cooper’s and sharp-shinned hawks, both in the accipiter family, spend much time in barnyards adeptly stalking and nabbing both pigeons and house sparrows. In addition, raccoons, opossums, foxes, snakes, rats, cats and dogs all help themselves to both adult and nestling birds when the opportunities present themselves.
HPAI
As cases of the highly pathogenic avian influenza continue to rise, pigeons are faced with yet another obstacle to their success, as cases of the deadly H5N1 are detected in the birds. Since this is a developing story, the best way to keep up with new outbreaks is to visit the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service website at www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/wild-birds.
Partners In Flight, an organization dedicated to bird conservation, estimates the global breeding population of pigeons to be 120 million with 7% living in the United States. These staggering statistics practically assure that pigeons will always be present. With help from us humans, they have come to thrive, carve out a niche in close association with us and will forever be a bane for farmers.
Video
To view a recent video of pigeons in action at local group of corncribs and their characteristic flight, visit https://youtu.be/LUh4NPTer9U.
