When Sexes are Alike

These Canada jays could be males, females or one of each. It is almost impossible to tell.


Of the seven bird species that visited my home this winter in Island Park, I could only tell male from female on one species. This was the hairy woodpecker, where the male has a dime-sized red spot on the back of his head that the female lacks. For the remainder, Steller’s jays, Canada jays, Clark’s nutcrackers, red-breasted nuthatches, mountain chickadees and the single visit from a black-billed magpie, they could have all been males, females or a mix and I could not tell.

That isn’t to say that an expert couldn’t tell the difference with enough observation, but the normal things such as size, very different coloration or ornamentation were not obvious giveaways. From my perspective, even when looking at the photographs later, I simply could not determine the sex of the bird.

I can think of many examples throughout the bird world where sexes are similar in appearance. Canada and snow geese, trumpeter swans, bald and golden eagles, gray partridge, chukars, ptarmigan, storks, flamingos, ravens, crows, creepers, song sparrows, cedar waxwings, titmice, gulls and shorebirds such as black-necked stilts and willets, are just a few. They are represented in many families. It is clearly a different strategy than birds with dimorphic (different looking) sexes.

Scientists have been interested in the subject of sexual dimorphism or the lack of it for centuries. For sexually dimorphic species, the evidence points to sexual selection as the driver of bright or even bizarre decoration: the more colorful, ornamented or larger the bird (or other animal for that matter), the more likely that the individual will be selected by a mate. I am careful not to say male, because there are a number of cases where the female is the more colorful, embellished or larger of the sexes.

This actually works in opposition to Charles Darwin’s original theory that all adaptations were selected for their value to the survival of the individual. A peacock’s tail serves no survival advantage; in fact, it is quite a liability except for the fact that the peahens love it. So, in the case of sexual dimorphism, the costlier the trait (to survival), the more valued for breeding because the battle isn’t for survival but for breeding rights. This pushed Darwin into an evolution of his own and he modified his theory by coining the term, sexual selection, as a special case of natural selection.

With sexually similar species, the current belief is that natural selection (not sexual selection) drives their evolution. Genetic traits become more or less common depending on how they influence an individual’s ability to survive and gather resources.

While we humans may have trouble identifying males and females in sexually similar species, that doesn’t seem to be a problem at all for the birds. They use calls, songs and behavior as ways to help recognize individuals and sexes, but in reality, birds see the world differently than humans. They can see a whole range of colors in the infrared spectrum that humans can’t see. To us, the black feather of a crow is just black. To another crow, it may be a color or colors that we can’t even imagine. One study indicated that when using a spectrophotometer to measure color differences, including infrared, between males and females, 92 percent of the species that we consider as having look-alike sexes have distinct plumage differences that only the birds can see.

There is a lesson in this: Just because we can’t see or understand something, doesn’t make it less real. Most of technology we enjoy today is based on things we cannot see.

 


Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

Wildlife License Plates

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program. Go figure. 


"WOW. What a phenomenal piece you wrote. You are amazing." Jennifer Jackson

That is embarrassing but actually a fairly typical response to my nature essays. Since The Best of Nature is created from the very best of 16 years of these nature essays published weekly in the Idaho Falls Post Register (online readership 70,000), it is a fine read. It covers a wide variety of topics including humorous glimpses of nature, philosophy, natural history, and conservation. Readers praise the style, breadth of subject matter and my ability to communicate complex and emotional topics in a relaxed and understandable manner.

Everyone can find something to love in this book. From teenagers to octogenarians, from the coffee shop to the school room, these nature essays are widely read and enjoyed.

Some of the essays here are my personal favorites, others seemed to strike a chord with readers. Most have an important message or lesson that will resonate with you. They are written with a goal to simultaneously entertain and educate about the wonderful workings of nature. Some will make you laugh out loud and others will bring a tear to the eye and warm your heart.

Readers Write:

"You hit a home run with your article on, Big Questions in Nature. It should be required reading for everyone who has lost touch with nature...great job!" Joe Chapman

"We enjoyed your column, Bloom Where Planted. Some of the best writing yet. The Post Register is fortunate to have your weekly columns." Lou Griffin.

To read more and to order a copy, click here or get the Kindle version 

here

Copies are also available at:

Post Register

Barnes and Noble in Idaho Falls

Harriman State Park, Island Park

Museum of Idaho

Valley Books, Jackson Wyoming

Avocet Corner Bookstore, Bear River National Wildlife Refuge, Brigham City, Utah

Craters of the Moon National Monument Bookstore, Arco, Idaho


TAX DAY is coming! Here is a chance to do something good with a bit of your tax return and make the day less painful.

Donate part of your tax return to support wildlife in Idaho!

On the second page of the Idaho Individual Tax form 40 you have the opportunity to donate to the “Nongame Wildlife Conservation Fund”.

Check-off this box on your next return or ask your tax preparer to mark the Nongame check-off on your behalf.

If you are not from Idaho, check with your own state wildlife agency about how you can help. Many states have a similar program.