Skip to main content

Colorful birds get the chicks

A bright male House Finch, Carpodacus mexicanus. This guy should be a real chick magnet. Photo by John Pogacnik.

Females drive A LOT of what we males do. And not just behavior. Over the long haul, through a process known as sexual selection, the girls even can change our appearance.

At least that's the case with House Finches, and many other birds.

Sexual selection is an evolutionary bology term that speaks to the process of the development of certain traits that are driven by competition between members of one sex, in order to better attract members of the opposite sex. This, as might be expected, is much more pronounced in males.

Sexual selection was first proposed as a theory by Charles Darwin in his watershed book On The Origin of Species. In the 151 years since, scientists have taken sexual selection beyond the realm of theory, and learned much more about how the overwhelming urge to attract a mate and reproduce ultimately influences physical appearance.

The common House Finch, a songbird that now ranges far and wide across the North American continent and is abundant in Ohio, is a wonderful example of sexual selection. Male House Finches are quite variable in coloration, as anyone who has watched large numbers of them at their feeders knows. They can range from yellowish to orange to a rich rosy red, with all sorts of varying levels of intensity.

This variation in color certainly doesn't escape the discerning eye of the ladies. Geoff Hill at the University of Michigan suspected that color variation means a lot in regards to the ability of males to score with females, and designed an experiment to prove it. Using dyes, he created uber-finches that were super bright or, conversely, dimmed them down in intensity.

The result? The bright guys attracted more mates, and the females abandoned the nests of these pairings far less often than they did when dim guys were involved.

Why would female House Finches be attracted most strongly to the brightest males? Because these males tend to be better providers. They seem to be better foragers, and thus - as males help care for young - provide the nestlings with more food, upping their chances of survival. Bright colors in males also signal that they are healthy, as their coloration stems from carotenoid pigments from the food they eat. So, the brighter the finch, the better it is at finding food, which makes for a healthier bird, and ultimately a better provider for the young, in which the females invest a significant allotment of their resources to produce.

So, over the long haul, one would expect male House Finches to become increasingly colorful, as the genes of the brightest males are constantly favored in the process of sexual selection and passed along to the offspring.

I wonder what House Finches will look like in 25,000 years?


dAwN said…
Yeah.. What will they look like? Cardinals? Interesting..wonderful post as always Jim..
Anonymous said…
So Jim, are you going to start wearing only hot pink outfits from now on? Lol.
Jim McCormac said…
Glad you enjoyed the post, dawn, thanks for the comment!

"Anonymous": um, no thanks, I prefer cross-assortative mating. But really great comment. Really.
flux biota. said…
can you make a blog entry about anomolies in the bird world? I found this entry pretty interesting.
Birding is Fun! said…
Love your blog Jim and the interesting content. At what point does bright color become a liability due to increased exposure to predators? Does predation keep the color evolution more stable?
Jim McCormac said…
Glad you liked the post, Flux Biota - I'll see what I can do.

Good question, Birding is Fun, and I don't know the answer. Only time will tell, and I doubt any of us will be around long enough to see if House Finches brighten up to the level of male Northern Cardinals or beyond.

It's been estimated that Purple and Cassin's Finches split from their House Finch-like ancestor some 9.3 million years ago, and all of these species are still pretty similar.

Evolution can take a LONG time.

Popular posts from this blog

The Pinching Beetle, a rather brutish looking bug

The world is awash in beetles, and they come in all shapes and sizes. Few of them can match the intimidation factor of a Pinching Beetle, Lucanus capreolus, though. Those formidable looking mandibles look like they could slice off a finger.

Today was one of those coolly diverse days. I started off down in Fayette County, visiting the farm of a friend. He has restored about 25 acres of wetlands, and the response by the animal community has been nothing short of phenomenal. Blizzards of dragonflies of many species, amphibians galore, and nesting Blue-winged Teal, Pied-billed Grebe, and Sora. Among MANY other things. And all in a short two years. Add water and they will come.

Then, working my way home, I ducked into a Madison County cemetery that has a thriving population of Thirteen-lined Ground Squirrels, and shot images of our native prairie dog. Then, I stopped at a spot along Little Darby Creek, waded on in, and procured some pretty nice shots of various stream bluets and dancers. …

Calliope Hummingbird in central Ohio!

A hatch-year male Calliope Hummingbird strikes a pose. Small but tough, the hummingbird was feeding actively yesterday in 39 F temperatures. It frequents feeders and gardens at a home in Delaware County, Ohio, about a half-hour north of Columbus.

Fortunately, the wayward hummer appeared at the home of Tania and Corey Perry. Tania is a birder, and knew right away that the hummingbird was something special. For a while, the identification was up in the air, which isn't surprising. The Calliope Hummingbird used to be placed in its own genus, Stellula, but has recently been submerged into the genus Selasphorus, which includes Allen's, Broad-tailed, and Rufous hummingbirds. The latter two, especially, are quite similar to the Calliope in subadult plumage. Rufous is the default "vagrant" hummingbird here, with dozens of records and birds turning up annually. There is but one Ohio record of Allen's Hummingbird, from late fall/early winter 2009. Ditto the Calliope Hummi…

Snowy owl photography tactics - and things NOT to do

A gorgeous juvenile female snowy owl briefly catches your narrator with its piercing gaze. It's doing its Linda Blair/Exorcist trick - twisting its head 180 degrees to look straight behind. Owls have 14 neck vertebrae - double our number - which allows them such flexibility.

These visitors from the high arctic have irrupted big time into Ohio and adjacent regions, with new birds coming to light nearly every day. Probably 80 or so have thus far been reported in the state, and some of them have stuck around favored spots and become local celebrities.

I went to visit one of these birds this morning - the animal above, which was found last Friday by Doug Overacker and Julie Karlson at C.J. Brown Reservoir near Springfield. In the four days since its discovery, many people have visited as is nearly always the case when one of these white wonders appears near a large population center or is otherwise very accessible.

And as is always the case, people want to photograph the owls. And th…