Passenger Pigeon

The Passenger Pigeon, a bird native to eastern North America, was the only species within its genus. DNA research on Passenger Pigeon specimens reveals that approximately 12 million years ago, the Passenger Pigeon shared a common ancestor with a cluster of North American pigeons now classified under a New World pigeon genus (Patagioenas), including the extant Band-tailed Pigeon, but subsequently underwent significant genetic divergence¹.

The Passenger Pigeon measured about 40 centimeters in length, making it larger than any existing North American pigeon, including the largest living North American pigeon - the Band-tailed Pigeon (the commonly seen Rock Pigeon in urban areas typically measures just over 30 centimeters). The Passenger Pigeon exhibited sexual dimorphism: males had a grayish-blue coloration from head to back and a cinnamon-red underbelly, while females displayed similar but duller hues and were slightly smaller.

Once astonishingly abundant, the Passenger Pigeon population was estimated in the billions, making it the most numerous bird species to have ever existed in North America and possibly the world. These pigeons could fly at speeds of up to 100 kilometers per hour, forming enormous nomadic flocks that migrated repeatedly, selecting large tracts of deciduous forest as habitats. They fed on various tree species, nesting and raising their young in the trees. The Passenger Pigeon bred in the spring, laying 1-2 eggs per clutch.

In the latter half of the 19th century, the Passenger Pigeon population plummeted due to massive² human hunting and habitat destruction caused by agricultural and industrial development. These factors led to a sharp decline in their numbers, making it impossible to sustain their highly social, predator satiation-based survival strategy, ultimately driving them to extinction. By the 1870s, Passenger Pigeons had become rare in the East of North America and moved towards less populated central regions. However, human hunting continued during their large-scale nesting periods, leading to their eventual disappearance in the wild. The last recorded wild sighting was on March 12, 1901³, near Oakford, Illinois, where a male Passenger Pigeon was shot.

The last known Passenger Pigeon, Martha, died at 1 p.m. on September 1, 1914, at the Cincinnati Zoo, at approximately 29 years of age⁴.

Appearance #

• Male
  • Gray-blue head, red iris, wavy markings around the eyes, black beak
  • Iridescent neck, color changes with light
  • Gray-blue back, more pronounced blue on the lower back, transitioning to gray-brown tail feathers
  • Wing coverts are gray-brown similar to the back, with irregular black spots; primary and secondary flight feathers are darker gray-brown, secondary feathers have white edges
  • Central two tail feathers are gray-brown, the rest are white; underparts of the tail feathers are white
  • Throat and chest are rich reddish-brown, gradually fading to white on the belly
  • Legs and feet are red
• Female
  • Most features similar to the male but with duller colors
  • Tail is noticeably shorter than the male, iris is orange-red
• Juvenile
  • Similar to adult female, with white speckling on the shoulders, neck, and wings, giving a scaly appearance
  • Legs and feet are duller in color

Life History #

Breeding and Rearing #

Courtship and pairing occur within nesting colonies. During the breeding season, the male pigeon performs a unique wing-flapping courtship display, often conducted on a perch. A description of this display behavior is as follows:

August 1. The male often sits on a perch or ledge and flaps his wings for a long time as if preparing for flight, looking around attentively as he does so. For a small part of the time, especially at the beginning of each series, the wings may be held up without being spread and only slightly flapped; other times, they may be fully spread and flapped with the fullest amplitude, with the carpi coming within about 1 inch over the back. The only reason this flapping does not lift the bird is that it is not rapid enough, and the bird seems to hold tightly to the perch with its feet. As a result, the whole body, head, and tail rise and fall with each stroke. He generally stands obliquely along the perch, so that one wing comes down on each side of the perch, but even then, it often happens that one wing hits the perch with a very audible sound at every stroke. ⁵

During courtship displays, the male pigeon emits a “keck” sound, often accompanied by a single wing sweep. He also produces loud chattering and soft “keeho” sounds while performing large wing movements. As the male approaches the female, he presses closely against her, firmly pinning her down without lifting his wings, and makes the “keck” sound, followed by preening the underside of his wings. As their bond intensifies, the male places his neck over the female’s, resembling an “hugging.” If the female accepts the courtship, she will reciprocate the “hugging.” Both then engage in rough preening of each other’s feathers, appearing almost as if they are fighting⁶.

Like other pigeons, Passenger Pigeons engage in billing, resembling a kiss, before mating. Compared to other pigeons, their billing is somewhat perfunctory, with their beaks briefly grasping together, shaking momentarily, and then quickly separating, without any food exchange. During mating, as the male attempts to mount the female, she initially stands upright; this forces the male to flap his wings for an extended period, positioning himself near her neck until the female tires and crouches down, allowing for copulation. After mating, the male assumes a posture similar to one of fear (as if before a fight), with his head drawn in, feathers puffed, and emitting a soft, toneless sound. The female also clucks softly, lifts her wings, and strikes them two or three times against the male—a post-mating behavior unique to Passenger Pigeons. Sometimes, after mating, both pigeons stand upright and nervously and rapidly tickle each other’s heads for a few seconds.⁵

Passenger Pigeons built their nests in trees within their habitats, with nests extremely densely packed. There are accounts of finding over 100 Passenger Pigeon nests in a single tree, often more than 90⁷. The nests were rather simple, made of a few twigs with minimal depth, essentially flat⁸. During nest-building, the male would stand on the female’s back, delivering one twig at a time to her. During nesting season, the sounds from the massive flocks of pigeons were extremely loud and could be heard from four or five miles away⁹. Due to the extremely dense environment, male pigeons would become jealous and aggressive towards other Passenger Pigeons approaching their nests and mates. After egg-laying, the males would no longer be jealous of other pigeons approaching the female but would continue to guard their nests⁵. Males would stay in the nest from 10 a.m. to 3 p.m., while the females went out, and outside these hours, the females incubated the eggs. Even during the breeding season, parents would commute between their nightly roosting sites and nesting areas (often in the same region but not the same forest) to feed.

Newly hatched chicks were fed “pigeon milk” by both parents for several days. The rearing period lasted about two weeks, after which the parents would leave the chicks, rejoining the flock and flying away. The chicks would spend three to four days feeding themselves, quickly growing, and then, like the adults, join the flock and fly away¹⁰.

Although Passenger Pigeon breeding colonies were vast, cooperative breeding was not observed. However, if parents were lost or killed (which was common), other adult Passenger Pigeons would feed orphaned chicks. Additionally, orphaned Passenger Pigeons would actively beg for food from other adults. A Potawatomi chief, Simon Pokagon, observed:

I have seen as many as a dozen young ones assemble about a male, and, with drooping wings, utter the plaintive begging notes to be fed, and never saw them misused¹¹ at such times by either gender.¹²

This “indiscriminate” care for orphans is a unique behavior among pigeons¹³.

Diet #

Passenger Pigeons mainly fed on various fruits and seeds, with a diverse diet that changed seasonally. A list of their diet written in early 19th-century included: beech nuts, acorns, buckwheat, hemp seeds, Indian corn, holly berries, hackberries, huckleberries, and rice seeds¹⁴. They foraged on the ground and frequently ate small ground-dwelling insects such as snails and worms¹⁵. They had a particular fondness for earthworms. Reports indicate that captive pigeons showed significant improvement in vitality and health after consuming earthworms¹⁶. Their feeding speed was quite fast. Records indicate that female Passenger Pigeons pecked an average of 12 times every 5 seconds. During pecking, the arc of their head movement was very large. ⁵

The diet of captive Passenger Pigeons included a mix of seeds, grit, oyster shells, salt, and plenty of green food, such as lettuce. ⁵

Observations noted that flocks foraging in the woods primarily consisted of males and juveniles (easily distinguishable by their color), suggesting that males were responsible for feeding the incubating females and the young¹⁷.

Behavior and Communication #

Passenger Pigeons were awkward walkers, with a gait similar to other pigeons. They primarily foraged on the ground and were generally quiet. Observations of live birds noted that males walked about 12-13 steps every 5 seconds.

Passenger Pigeons were most active in the early morning. Males were described as having a bluffing, bravado-like aggressiveness, often flapping their wings to intimidate rivals, but rarely engaging in actual fights. ⁵

Wallace Craig once described five distinct calls of the Passenger Pigeon:

1. The Copulation-note: Similar to the soft cooing sounds made by the Mourning Dove (Zenaida macroura) during mating, characterized by gentle, low-pitched murmurs.

2. The Keck: A loud, harsh, and high-pitched “keck” sound, often used to intimidate other birds. This call is typically followed by other sounds, such as cooing.

3. Scolding, Chattering, Clucking: The most characteristic communication sounds of the Passenger Pigeon, described as “Kee-kee-kee” or “Tete! Tete! Tete!” These calls vary greatly. When highly excited, the sounds become loud and high-pitched; during fights, they become very rapid. In calmer moods, the calls soften into a gentle, low-pitched adagio. Although not melodic like songbirds, the varying tones make these calls highly expressive.

4. The Vestigial Coo or Keeho: A weak, somewhat musical coo, often following the chattering calls as a concluding sound. It is hypothesized that due to the Passenger Pigeon’s extremely large flocks, louder calls evolved for better communication, while the soft “keeho” coo became vestigial.

5. The Nest-call: Made by the bird when in the nest, often during moments of slight nervousness. Though the context of use is similar to that of the Mourning Dove, the sound is markedly different. The timbre is more burred than that of other pigeon species, with a mix of high and low tones, moderately loud and half-musical. The series consists of at least 8 notes, often more, and if the series is long, it falls slightly in pitch. This call usually ends with a “keeho.”⁵

Nomadic Life #

Passenger Pigeons formed large groups and migrated nomadically, seeking vast forests capable of supporting their food needs. They primarily inhabited large beech, pine, and hemlock forests in the eastern United States, without a regular migratory rhythm¹⁸.

Passenger Pigeon flocks rarely crossed large bodies of water as they could not swim, and there were reports of large numbers drowning. However, they frequently flew over the Great Lakes, with some sightings along coastlines¹⁰.

When large flocks were feeding, some sentinel birds acted as guards to alert others of danger. Upon detecting a threat, the sentinel birds would signal the alarm by rapidly flapping their wings, producing a sound like “rolling beat of a snare drum”. This would cause the entire flock to take flight in a panic, with the simultaneous beating of their wings creating a thunderous noise.¹⁹

Human Persecution and Extinction #

Native Americans and early settlers extensively hunted Passenger Pigeons for food, but it was not until the rise of commercial pigeon hunting in the 19th century that the population faced a fundamental threat. Some Native Americans held beliefs about Passenger Pigeons²⁰. At the time, people generally considered Passenger Pigeons an inexhaustible resource.

An early 19th-century method of hunting Passenger Pigeons involved sewing the eyelids of some live pigeons shut and fixing them on a movable stick. By pulling a string from a distance, the stick would rise and fall, creating a sound similar to pigeons landing. Passing flocks would be lured down to peck at bait like corn and buckwheat on the ground, and the hunter would pull the string to trap the pigeons under a net, catching ten to over thirty pigeons at a time²¹.

In the summer of 1878, during the last major commercial pigeon hunt near the Great Lakes, at least 300 tons of Passenger Pigeons were shipped out of Michigan²². From the small city of Petoskey alone (near the Great Lakes, the last major nesting site), 1.5 million dead pigeons were shipped²³.

In May 1880, at the last known nesting site in a birch forest near the Platte River in Benzie County, Michigan, people set trees on fire, causing the frightened adults to fly and the clumsy young to fall to the ground, where they were captured by humans. Thousands could be caught this way in a single day²⁴.

The expansion of the railway system in the mid-19th century is considered a significant factor in the Passenger Pigeon’s extinction, as it made large-scale commercial pigeon hunting a viable industry. Although commercial hunting had existed before, it had never been so efficient. The development of the telegraph also allowed professional hunters to quickly learn the pigeons’ whereabouts¹⁰. Thus, the extinction rate of the Passenger Pigeon might have been more rapid than imagined, with the population plummeting from billions to extinction in less than a century. Additionally, the deforestation of oak and beech trees, their common habitats and food sources, accelerated their extinction.

For a long time, it was believed that the last wild Passenger Pigeon was shot on March 24, 1900, near Sargents, Ohio, by 14-year-old Press Clay Southworth. This female pigeon was later preserved as a specimen and named “Buttons” because the taxidermist used shoe buttons for its eyes instead of glass beads²⁵.

Recently disclosed materials revealed a later record: on March 12, 1901, a male Passenger Pigeon was shot near Oakford, Illinois³. Regardless, wild populations of Passenger Pigeons certainly went extinct before those in captivity.

The last Passenger Pigeon, a female named Martha, died at the Cincinnati Zoo on September 1, 1914, at 1 p.m. Before her, a male pigeon named George, also kept at the zoo, died on July 10, 1910²⁶. Martha lived alone after George’s death, with all breeding attempts unsuccessful. Martha died of old age; she had been unable to perch higher in her later years, living at the bottom of her cage, where she was found dead. On August 18, 1914, a few days before her death, there was a report that a zookeeper found Martha collapsed at the cage’s bottom, unresponsive. However, after throwing some sand at her, she startled, regained some energy, and ate a lot of food, which might have been a final burst of energy¹⁰.

Accounts #

• The famous early American ornithologist Alexander Wilson (1766 - 1813) documented some scenes of the Passenger Pigeon populations in their prime:

  It sometimes happens that having consumed the whole produce of the beech trees in an extensive district, they discover another at the distance perhaps of sixty or eighty miles, to which they regularly repair every morning, and return as regularly in the course of the day, or in the evening, to their place of general rendezvous, or as it is usually called, the roosting place. ‘These roosting places are always in the woods, and sometimes occupy a large extent of forest. When they have frequented one of these places for some time the appearance it exhibits is surprising. ‘The ground is covered to the depth of several inches with their dung; all the tender grass and underwood destroyed; the surface strewed with large limbs of trees broken down by the weight of the birds clustering one above another; and the trees themselves, for thousands of acres, killed as completely as if girdled with an axe.²⁷

  A few observations on the mode of flight of these birds must not be omitted. The appearance of large detached bodies of them in the air, and the various evolutions they display, are strikingly picturesque and interesting. In descending the Ohio by myself in the month of February, I often rested on my oars to contemplate their aerial manceuvres. A column, eight or ten miles in length, would appear from Kentucky, high in air, steering across to Indiana. The leaders of this great body would sometimes gradually vary their course, until it formed a large bend of more than a mile in diameter, those behind tracing the exact route of their predecessors. This would continue sometimes long after both extremities were beyond the reach of sight, so that the whole with its glittery undulations, marked a space on the face of the heavens resembling the windings of a vast and majestic river. When this bend became very great, the birds, as if sensible of the unnecessary circuitous course they were taking, suddenly changed their direction, so that what was in column before became an immense front, straightening all its indentures, until it swept the heavens in one vast and in- finitely extended line.. Other lesser bodies also united with each other, as they happened to approach, with such ease and elegance of evolution, forming new figures, and varying these as they united or separated, that I was never tired of contemplating them. Sometimes a Hawk would make a sweep on a particular part of the column, from a great height, when, almost as quick as lightning, that part shot downwards out of the common track; but soon rising again, continued advancing at the same height as before; this inflection was continued by those behind, who on arriving at this point dived down, almost perpendicularly, to a great depth, and rising followed the exact path of those that went before. As these vast bodies passed over the river near me, the surface of the water, which was before smooth as glass, appeared marked with innumerable dimples, occasioned by the dropping of their dung, resembling the commencement of a shower of large drops of rain or hail. Happening to go ashore one charming afternoon, to purchase some milk at a house that stood near the river, and while talking with the people within doors, I was suddenly struck with astonishment at a loud rushing roar, succeeded by instant darkness, which, on the first moment, I took for a tornado about to overwhelm the house and every thing around in destruction. The people obserying my surprise, coolly said “It is only the Pigeons;” and on running out I beheld a flock, thirty or forty yards in width, sweeping along very low, between the house and the mountain or height that formed the second bank of the river. These continued passing for more than a quarter of an hour, and at length varied their bearing so as to pass over the mountain, behind which they disappeared before the rear came up.²⁸