Nature: Genetics play role in blue jay's lack of blue

An unusual white-headed blue jay prepares to visit the writer's feeders/Jim McCormac

NATURE: Genetics play role in blue jay's lack of blue

Columbus Dispatch

February 2, 2020

NATURE
Jim McCormac

In my last column, I wrote about an unusual melanistic fox squirrel. Although the average fox squirrel is dashing in tones of rufous and brown, this one is black. Dark forms of the eastern gray squirrel are well-known in Ohio, including Columbus, but melanin-enriched fox squirrels are far scarcer.

The dark fox squirrel turned up in my Worthington backyard on Jan. 9. Three days later, I glanced out the back windows and did a double-take. A blue jay with a white head was wolfing down seeds at the feeder.

I’m writing this column on Jan. 26, and both of these odd critters are still frequenting the yard. Sometimes at the same time, which makes for interesting wildlife-watching.

The squirrel looks as he/she does because of an excess of melanin, or dark pigment. It’s the opposite with the jay. He or she — it’s tough to impossible to determine sex in the field — lacks dark pigments only in the head and neck area.

Animals with localized patches of white often are referred to as piebald. Commonly seen examples include white-tailed deer and American robins. These animals can be splotched throughout with white, have pale heads or other localized concentrations, or occasionally are nearly all white. The latter examples differ from true albinos in lacking pink eyes, and normally aren’t as bright white.

The genetic condition that typically causes piebaldness is leucism, and splotchy animals are said to be partially leucistic (loo-sis-tic). When I first saw the unusual blue jay, that’s what I thought it to be — a partially leucistic specimen.

Leucism is a genetic condition that inhibits normal melanin deposition, causing dark areas to become washed out. But genetics that cause color anomalies are complex and imperfectly understood. One can get bogged down in complicated and perhaps unverifiable explanations for various pigment anomalies. Other factors might be at work with this jay.

Suffice it to say, this blue jay is an extraordinary avian no matter the explanation for its unusual coloration.

Odd color genetics is largely a numbers game. The more common the species, the more likely that leucism will manifest itself. That’s why deer, robins and other common animals are the most commonly seen species expressing color mutations.

There are an estimated 15 million blue jays in the U.S., so it’s not surprising that leucism would rear its head in this species on occasion. A quick internet search will reveal numerous examples, but few of them possess the showiness of “my” jay (in my biased opinion).

Naturalist Jim McCormac writes a column for The Dispatch on the first, third and fifth Sundays of the month. He also writes about nature at www.jimmccormac.blogspot.com.

White-headed jay continues on

This stunning white-headed blue jay appeared in my yard on January 12, and here's a photo from yesterday. He/she - although I dubbed it "Albert" - was out there raiding the feeders this morning. I wrote a bit more about this unique bird RIGHT HERE.

He's got a pretty good deal going here, with plenty of unshelled peanuts and other seedy fare. I hope he sticks around for some time. It's a gorgeous specimen, and really stands out from the typically pigmented jays, of which there are many to keep Albert company.

Perhaps the biggest threat is a good-sized (female, probably) Cooper's hawk that raids the yard daily. She's mostly after the house sparrows and smaller birds, but is more than capable of dispatching a jay. These hawks are incredibly aggressive and so cool to watch. Today, she ran into a dense forsythia shrub on foot in an attempt to rout the house sparrows lurking within. Hope she catches them all.

And now, a (partially) white blue jay!

So, just a few days ago, a melanistic fox squirrel appears in the yard. I wrote about that oddity in my last post. This morning I glance out the back window and what do I see? This strange and beautiful creature! It's a partially leucistic blue jay, absent the black (melanin) pigments that mark the face and neck of a typical jay. When I first saw the bird, it was consorting with several other jays at a feeder, and it stuck out like a sort thumb.

NOTE: I am referring to the animal as partially leucistic, even if that's being a bit general. One can get extremely bogged down in what seems to be largely unverifiable explanations for various conditions of pigment anomalies. For a good general discussion about anomalies in pigmentation, with a key to place birds into six general categories of color aberrations, CLICK HERE.

As a frame of reference for our odd jay, here is a typically plumaged blue jay. The black collar, eye line and dark saddle across the base of the bill are conspicuous plumage highlights of a blue jay.

Thanks to Julie Zickefoose (she authored THIS BOOK about blue jays) for aging this jay as a hatch-year bird (born last spring/summer). Whatever all the factors that caused its excessively snowy plumage, it is a beauty. The jay has been coming in to the feeders intermittently today, usually in the company of several other jays. I hope he sticks around. I'll certainly try and help by keeping the jay smorgasbord going.