When you think of romance between birds, perhaps Monty and Rose, arguably Chicago’s most famous bird couple, come to mind. This Piping Plover pair captivated Chicago from 2019 to 2021. But every year, numerous birds around the Chicagoland area signal their willingness to pair up, mate, and form a family. Ardor to a bird comes in many varieties. It can be…
…monogamous
Mallard, male and female
Caroline Lambert/Audubon Photography Awards
Monogamy is actually the primary relationship structure for birds, although its definition can be flexible. Some birds form a pair bond just for one nesting, such as House Wrens. Most bird species will be monogamous for a breeding season, and some pairs of birds will even be monogamous for several successive seasons. A few species, such as Trumpeter Swans, may pair for life.
Having both mother and father as active parents helps ensure that the children survive. A study titled “Evolution of sexual cooperation from sexual conflict“ dove into an intriguing mystery - that for some species that develop pair bonds, male birds will actually initiate courtship rituals after mating. The short answer to the question why is that this display of romance strengthens the pair bond and incentivizes his female counterpart to take a deeper interest in their young. It would seem at first glance that the male bird’s time would be better spent taking care of his progeny and mating with multiple female birds to spread his genes; however, these displays of affection seem to be necessary in prolonging a female bird’s interest in child-raising and accepting the imbalanced division of labor.
…polygynous
Red-winged Blackbird, male and females, Texas
Gary Leka/Audubon Photography Awards
Although monogamy is the dominant relationship system, there are certainly birds that deviate from the norm. Some birds, for instance, are polygynous, where the male has more than one mate. This is theorized to occur when male birds hold sway over varying quality of territory, and a female bird can choose to either pair with a male who oversees a less impressive area or share a mate who possesses superior land. If there is a sizable enough difference in quality, a female might choose the latter.
The Red-winged Blackbird is one such example where there is evident correlation between territory quality and ability to attract a mate; in fact, some males have been spotted with 15 partners. The Dickcissel is another bird you might be able to spot in Chicago that practices polygyny. The male could have up to six mates, although typically there are one or two females with him. The better the nest site, the more attractive the male becomes to the female.
…polyandrous
Spotted Sandpiper, Juanita Bay Park, Kirkland, Washington
Mick Thompson
The Spotted Sandpiper practices polyandry, which is when a female has multiple partners, and is highly unusual for birds. This sandpiper breeds in a more temperate climate than most other sandpipers, and therefore experiences a longer breeding season. Breeding females live a relatively short lifespan - only 3.7 years - and they attempt to lay many eggs a year. The breeding season is heavily influenced by the number of insects sandpipers subsist on. When the insect population is anticipated to decline in July, the breeding season winds down.
Females compete for males, and it is really the number of available partners that determine how many eggs get laid. A sandpiper can lay up to 4 eggs in one clutch, and lay 5 clutches in a breeding season. However, due to mate scarcity, she will normally lay about eight eggs during this time. Initially there are more females vs. males at the breeding grounds, so there is always intense competition upfront. The number of birds increase as the season continues, but since males are the ones incubating the eggs they are essentially out of the dating pool once eggs are laid.
…found on land
Mourning Dove, male and female, Ocean county, New Jersey
John Dante Jr./Audubon Photography Awards
When a male Mourning Dove goes to court a female, he flies up with boisterous wingbeats then transitions into a circular glide. Here his wings are fully spread out and somewhat bowed down. Once he lands, the male will approach the female with his chest out, bowing and cooing. These birds are monogamous and can be found preening each other in a sweet gesture of bonding.
Their cousin, the Rock Pigeon commonly found around the city, starts his courtship with an advertising coo. After an interested female comes by, he will inflate his crop, stand tall, then bow down and make a display coo. All the while, he is walking around in a circle with his flared tail on the ground. If the female is still intrigued, the couple will preen each other and engage in a kissing gesture known as ‘billing’. This is when the female pecks the male’s beak; when he opens, she will put her beak in his and they will bob their heads together.
…found on water
Pied-billed Grebe, Columbia, South Carolina
Leonard Billie/Audubon Photography Awards
Grebes spend most of their time in the water and unsurprisingly, courtship takes place there. The Horned Grebe has a complicated courting ritual that encompasses posturing by both sexes. They rise upright with fully raised head feathers. Next, they dive and bring up bits of weeds. Afterwards they rush, or sprint across the water, side by side, holding the weeds in their bills.
The Pied-billed Grebe, the most commonplace grebe in this state, has its own take on courtship. Their dance involves ‘advertising’, where a single grebe, male or female, will swim around with an elongated neck, hoping to attract a bird of the opposite sex. Once contact is established, they will approach each other, move into an upright posture and perhaps make a greeting call with ensuing head-turning jerks. They will then show off their swimming skills and circle each other.
…found in the air
Ruby-throated Hummingbird, Aiken, South Carolina
Barry Jerald/Audubon Photography Awards
It is difficult to say for certain whether the Ruby-throated Hummingbird is polygynous or polyandrous, but the male will put on a show to woo a potential mate. When a female happens to arrive in his territory, the male will fluff out his gorget, or throat feathers, and pursue the female. He will fly in a U-shaped arc, back and forth, starting perhaps 12-15 meters above the other bird with an arc length of one meter or less. If the female decides to perch, the male hummingbird will then start a series of horizontal arcs within 0.5 meters of his audience. These arcs are rapid; the wings of the male might be beating up to 200 times/second at this point, while normally his wings are fluttering at 90 beats/second. If the female is interested, she may pose with her wings drooped and tail feathers cocked, and make a ‘mew’ call.
It is fascinating to learn about the myriad ways our Chicagoland birds, and birds around the world, engage in to attract or choose a mate. Between the diverse and elaborate courtship displays and the savvy calculations that go into picking a partner, the love life of birds is an absorbing topic with much to learn about.
Sources
Monogamy
https://www.iowadnr.gov/About-DNR/DNR-News-Releases/ArticleID/888/4-Cool-Things-You-Should-Know-About-Trumpeter-Swans
Bird Love Is Forever: UChicago Professor Co-Authors Study on Bird Mates – Chicago Maroon
https://www.pnas.org/doi/10.1073/pnas.1904138116
Polygyny
Red-winged Blackbird Overview, All About Birds, Cornell Lab of Ornithology
Dickcissel - American Bird Conservancy
Polyandry
Polyandry in the Spotted Sandpiper
Land
https://www.audubon.org/field-guide/bird/mourning-dove
https://www.chesapeakebay.net/news/blog/mourning-doves-raise-multiple-broods-each-year
https://animaldiversity.org/accounts/Zenaida_macroura/
Birds, Familiar: Mourning Dove, Life Histories of North American Birds, A.C. Bent
Mosco, Rosemary. A Pocket Guide to Pigeon Watching: Getting to Know the World's Most Misunderstood Bird. Workman Publishing Co., Inc., 2021.
Water
Podiceps auritus (horned grebe)
https://nanpa.org/2021/06/18/grebes-walk-on-water-to-find-a-mate-2/
https://www.audubon.org/field-guide/bird/horned-grebe
Podilymbus podiceps (pied-billed grebe)
OutdoorIllinois May 2010 The Grebes of Illinois
Air
Archilochus colubris (ruby-throated hummingbird)
Ruby-throated Hummingbird | Audubon Field Guide
A Hummingbird's Shining Armor | Audubon
Weidensaul, S., T. R. Robinson, R. R. Sargent, M. B. Sargent, and T. J. Zenzal (2020). Ruby-throated Hummingbird (Archilochus colubris), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.rthhum.01
Monty and Rose