The subjects of love, sex and relationships have transfixed people for longer than we can possibly know. The many different ways people carry out their love lives are a celebration to some, and an abomination to others…and no matter if we approve or not, it makes for great gossip. Everyone has an opinion on monogamy, open relationships, extra-pair copulations (to borrow a scientific term) on the side, etc.
When people think of birds and their sex lives…most of us don’t know much, although it’s not for a lack of interest. Some brief mating scenes from a nature documentary may come to mind, but most people just aren’t exposed to this subject more than that. Within the bird world, so many different strategies and methods of mating and reproduction have evolved, it simply boggles the mind. As the reigning birder of the world, I feel it is only right to look a little deeper into the lives of birds here, and talk about something beyond the mundane nuances of plumage variations of freshly-molted Empidonax flycatchers and if migrant Warbling Vireos arrived 3 days earlier this year than last. There is no room for that today….no. This week at 10,000 Birds, it’s all about how birds get around to bumping uglies (I’m talking about cloacas here), who they do it with, and how this actually leads to raising chicks…the birds and the bees of birds, you might say.
I also want people to know that our understanding of birds’ mating habits are constantly changing and evolving…there is still a lot of research to be done here, and we will be learning a lot more in the years to come. This is just a small slice of how birds get it done.
When it comes to breeding, Yellow-rumped Warblers are a good example of what many people regard as a “regular” bird. They molt into flashy bright colors in the spring, males sing songs to attract mates and defend territories, and they have short-lived, monogamous relationships. Male and female Yellow-rumps pair up on their breeding grounds, share duties in raising chicks, then politely part ways when fall migration comes.
Believe it or not, this is what “fidelity” looks like. Greater White-fronted Geese are one of many species that mate for life. Aside from geese, various albatross, alcids, eagles, owls, cranes, swans and condors have life partners as well. We can’t very well ask these birds themselves or test this in a lab, but there is a large body of anecdotal evidence demonstrating that individuals of these species really can have feelings for one another.
Many hummingbirds, like this Anna’s Hummingbird, have a pretty simple system for getting it done. Males will often perform elaborate courtship flights to impress females, which is an extremely energy intensive activity for such tiny birds. Once they have shown off properly and mated, the male has no involvement in any nest-building, incubating or raising of chicks…while the female is busy with this, he sets out to find another mate. Males are after a polygamous lifestyle, and will frequently mate with multiple females in a given breeding season…some literature describes this situation as a “harem”, where the female carries out all the nesting duties, there is no real pair bond, and a male has several mates.
Extra-pair copulations (or anthropocentrically speaking, “cheating”) is not rare in the bird world, for either gender. There is some debate on the reproductive/genetic benefits of this, although a common view is that individuals don’t want all their eggs in one genetic basket, so to speak (pun intended, zing!). Female Northern Fulmars are known to make some sly hook-ups with other handsome male fulmars when they can.
Despite how familiar you may be with sights and sounds of Red-winged Blackbirds, you may not know what is going on down in the reeds. Red-wings are polygynous; males have multiple mates (sometimes in the double digits!), while the female has one primary mate. However, females will get some on the side as well, and clutches can be of mixed paternity.
In Wilson’s Phalaropes, the typical sex roles are reversed. Females are much larger and more colorful than their male counterparts, and will fight one another for the rights to mate with several males (this is known as polyandry). After laying eggs, they have little to do with the upbringing of their chicks, leaving the male to handle things. By the time nests are starting to hatch, many females are already beginning their southbound migrantions.
Although you wouldn’t know it by their appearance, Dunnocks are very sexual birds. Seriously, I am blushing as I write this. Anyways…females are frequently polyandrous, mating with more than one male. This situation doesn’t make any of her mates very happy though, so they are constantly trying to mate with her, to make sure their sperm is the stuff she’ll actually use to make more Dunnocks. To take it to another level, males are constantly pecking at her cloaca, to make her eject any sperm she might have in there from other individuals. Ouch. Dunnocks who aren’t this kinky will have monogamous relationships, but other Dunnocks will be polygynous or even resort to polygynandry, with 2 males and 2 females swapping partners. Damn. Photo courtesy of Redgannet.
Ducks, like these Chiloe Wigeon, are infamous for their violent, sometimes forced copulations. It is this tendency that is thought to have driven the development of extremely complicated “plumbing” in females, to keep unwanted male duck parts out. Not being slackers when it comes down to getting the best access to hens, male ducks have evolved absurd, outlandish-looking penises to be able to get in…but you know all about this already, because you read it here!
Redheads often follow a typical monogamous lifestyle, but many females are notoriously lazy…they will often lay their eggs in another ducks’ nest, sometimes belonging to a completely different species, hoping that this foster parent will do the chick-rearing for them. Other infamous brood parasites include cowbirds and Old World cuckoos. Apparently, they’re all about getting laid, and doing none of the work.
Whereas many species leave their winter flocks to go and find a mate in peace and quiet, birds like Elegant Terns join huge colonies to find mates and nest. Living in such close quarters, these birds have no qualms about public copulation, unlike most of the birders I know.
Some birds take to the air to woo partners, and do much of their seduction on the wing. Red-tailed Tropicbirds choose their mates, as far as we know, based on what they see during their flight performances, and possibly on the length and condition of their fantastic tail plumes. These specialized tail feathers are considered strictly sexual ornaments, in that they serve no function beyond courtship. Studies suggest that their length and state of molt are not an accurate indicator of a bird’s health and fitness, however, so no one really knows what the Tale of the Tropicbird’s Tail actually is.
Certain birds, like this completely facemelting Guinanan Cock-of-the-rock, prefer to lay it all out in one place. Males will gather to strut, dance, puff themselves up, and frequently fight each other, while females quietly decide who they want for a mate. Some famous lekking birds inculde Ruffs, Buff-breasted Sandpipers, manakins, and various grouse and prairie-chickens. Photo courtesy of Adam Riley.
Lastly, I’ll leave you with Laysan Albatross. Laysans (and other albatross) have been found to regularly form female-female pairs, who seem to have lasting pair bonds and even may raise a chick together. I’m not sure how they go about asking a male to step in a be a sperm donor though…
A fish may love a bird, but where would they live?
Bird Love Week is seven days of exploration of avian amore here on 10,000 Birds from April 22-28. We love birds, and the topic of birds loving other birds and in the process making more birds is a fascinating one we know you will enjoy. Mike, Corey, and a bevy of Beat Writers have been working on this one for awhile as the perfect expression of our love of all things avian. To see all of our Bird Love Week posts, just click here. But be warned – Bird Love Week is neither for the faint of heart nor for the permanently prudish – you may end up with images that you never imagined seared onto your brain.