The epaulette colours of red-winged blackbird males means something

It takes three years for a male red-winged blackbird to fully develop its characteristic red epaulettes.

I used to wonder why the epaulettes on some red-winged blackbird males were less spectacular than on others.  It turns out that it takes a few years for the familiar patches to develop.

In first-year males, the shoulder feathers are brownish or somewhat yellowed.  Very little red appears.  In the following year, the males show a transitional phase.  A significant red patch is present, unlike in the first year males, but it is not the fully developed spectacle present in the mature adult.  It takes another year before the epaulettes have blossomed to their full potential.

The bird's feathering also changes over time, with there being a brownish hue to them in the first and second year.  By the third year, the somatic feathers are fully black.  You can see the tinge of brown on the first three images above.

The strong, fully developed shoulder patches play an important role in breeding.  The bright red epaulettes demonstrate the maturity and desirable breeding genes of the males, attracting more females and better breeding areas.  Red-winged blackbird males are highly polygamous, having anywhere from 2 to 15 females within their defended territory.  There is a strong correlation between the number of females and the amount of red on the shoulder patches, with juveniles having less and mature birds having more.

The next time you see a red-winged blackbird male with those dazzling red epaulettes, you know that he has been successful in more than one way.

Thanks for reading.

Eric Svendsen     www.ericspix.com