Friday, July 19, 2024

A pigeon beneath Route 28 in Somerville. (Photo: Jeanine Farley)

Domesticated pigeons (Columba livia domestica) have been around for 10,000 years. They were one of the first animals to be domesticated. People raised these birds for food, as pets, as generators of excellent fertilizer and to carry messages. Over the years, many of these domesticated pigeons were released or escaped back into the wild, producing large feral populations worldwide. Feral birds, domesticated birds and wild birds can all interbred – so today it is not known if there are any true wild-type rock pigeons left in the world. (If there are any, they dwell in cliffs and sea caves in remote parts of Ireland and Scotland.)

The free-roaming pigeons in North America are feral birds, first brought over by early colonists in the 1600s as a source of food. Rock pigeons are not native to North America, and all the birds we see are descended from domesticated birds that escaped captivity. Through selective breeding, pigeons have been bred for many purposes, but one of their most useful qualities is their ability to return home. Wild rock pigeons roam far searching for food, and for this reason have developed a good homing sense. It helps them return safely to their mate – pigeons are monogamous and may mate for life – and roost each night.

Pigeons in downtown Boston during First Night. (Photo: Jeanine Farley)

Most other species of birds feed their chicks soft caterpillars and insects; some, such as goldfinches, regurgitate seeds for their young to eat. All are limited to reproducing only during the growing season.

Pigeons, however, do not have this restriction. Cells lining the pigeons’ crop slough off for their young to eat. (The crop is a pouch on a bird’s neck that stores extra food. If you see a bird with a bulging throat, its crop is full.) Unlike humans, female and male pigeons make “pigeon-milk.” They feed this thick pale yellow substance to their chicks. It is higher in both fat and protein than human milk, and unlike human milk, it contains no sugars.

Pigeons in Draw Seven Park in Somerville. (Photo: Jeanine Farley)

Pigeons start to produce this milk in their crop a few days before the eggs hatch. The parents stop eating so the crop will not have seeds or other food in it that the youngsters cannot digest. At first the parents feed the babies pigeon milk four times per day. As time goes on the parents eat again, so seeds and other adult food become mixed into the pigeon milk in the crop. By two weeks, the chicks are fed only softened food from the parents’ crops.

A pigeon in Somerville’s Draw Seven Park. (Photo: Jeanine Farley)

Crop milk takes a great deal of energy to produce, so pigeons normally lay only two eggs. They cannot produce enough pigeon milk to raise three chicks. If only one chick survives, that chick grows at a much faster rate than normal because it gets so much pigeon milk.

Adult pigeons will eat almost any food, but prefer seeds and berries. As we all know, pigeons also eat handouts and food waste that people leave behind. Because pigeons can produce pigeon milk all year long, they can raise 10 or more chicks per year. By six weeks old, youngsters are independent, and the parents may start another brood.

A pigeon visits Tufts University. (Photo: Jeanine Farley)

Some pigeons have been bred selectively to enhance their homing abilities. These homing pigeons can travel 500 miles in one day. During World War II, one American homing pigeon named GI Joe saved many lives. On Oct. 18, 1943, a U.S. infantry division prepared to bomb a German-occupied Italian village. The Germans retreated, though, and British infantry moved into the town. They tried to radio the Americans to cancel the bombing, but the messages were not getting through. As a last resort, the British sent the carrier pigeon GI Joe with a message on its leg to abort the bombing. GI Joe traveled the 20 miles in 20 minutes and arrived just as the bombers were preparing to take off. Thanks to GI Joe, the bombing was aborted and 1,000 British lives were saved.

Pigeons in Draw Seven Park in Somerville. (Photo: Jeanine Farley)

Homing pigeons, or carrier pigeons as they are sometimes called, were one of the most secure and reliable forms of communication during world wars I and II. Their messages were the least likely to be intercepted. In fact, because 95 percent of carrier pigeon messages got through, the messages were seldom coded. These pigeons traveled at about 50 mph. They were capable of traveling 2,000 miles, but their average flight distance was 25 miles. 

Although bomber crews who carried pigeons into war needed to wear oxygen masks and heated suits when flying at 20,000 feet, pigeons did not need special equipment. Even at temperatures 45 degrees below zero, the birds just fluffed their feathers and closed their eyes, suffering no apparent ill effects during the flight.

Pigeons enjoy a fountain along Boston’s Harbor Walk. (Photo: Jeanine Farley)

How do pigeons find their way home? Scientists think pigeons use several techniques, including using the angle and position of the sun to determine the correct direction in which to fly. Other methods may include listening to low-frequency sounds – that humans cannot hear – emitted by everything on Earth, including oceans and the planet’s crust. Pigeons have an excellent sense of smell and can use odors to help navigate. They can smell differences in the composition of the air in various locations. Pigeons may also sense Earth’s magnetic field, and of course once they get closer to home, they use their excellent memory to follow roadways, rivers and other familiar visual cues.

Pigeons are remarkable birds, and although many consider them to be pests, they have been a boon to humans for thousands of years.

A pigeon alights in a tree at North Point Park in Cambridge. (Photo: Jeanine Farley)


Seen nearby

Brian Hunter spotted this orange-crowned warbler in Lowell on Jan. 27.


Have you taken photos of our urban wild things? Send your images to Cambridge Day, and we may use them as part of a future feature. Include the photographer’s name, date and the general location where the photo was taken as well as any other relevant information.

Jeanine Farley is an educational writer who has lived in the Boston area for more than 30 years. She enjoys taking photos of our urban wild things.