Stop hitting yourself, stop hitting yourself, stop . . .

I have a question about a robin that is exhibiting strange behavior near our house. It continually tries to fly into (our sun porch) and hits the window. It doesn’t get hurt as it isn’t going very fast, but it does this for hours at a time. We are concerned it’s going to eventually hurt itself. We have tried scaring it away and it goes away for a while only to return and continue hitting the window. We have even pulled the curtain over the window and it still is hitting it. Any thoughts on why this bird is doing this? What can we do?

Thanks,

Jeff Nevins, Portland

It is not uncommon for robins or other red birds to bash into windows. The reflection they see of themselves can be misinterpreted by the birds as a competitor for their territory. AP

This becomes a remarkably common question each spring so I’m glad we could address it in this column. The breeding season for many of our resident birds has already started and birds are becoming very territorial. That increase in lovely bird song you hear each morning is the aggressive screaming of neighbors telling each other where their property boundaries are, and trying to impress and attract a mate at the same time. When a song doesn’t work to establish a territory, birds will become more aggressive, chasing and occasionally fighting one another.

So Jeff’s robin is seeing its reflection in the window and it thinks that it is seeing a competitor for its territory. The only logical solution, to that robin, is to attack! But with each swipe, the foe remains in the window! Repeat attack. This seems to be especially common in red birds: most reports we get of this behavior are about American robins and northern cardinals. My research into this left me with more questions than answers so if any physicists read this I’d love to know: does red reflect better, or farther? Perhaps it’s something to do with longer wavelengths but we’re stretching this naturalist’s knowledge of light transmission.

The solution is to break up that reflection. When it is darker inside than outside (almost all day), your window effectively becomes a mirror. Closing blinds or putting something inside the window unfortunately doesn’t change the darker-lighter equation so you’ll need to put something on the outside. Window screens are an easy solution but sometimes creativity is needed. I’ve had good luck taking a bar of soap and scribbling on the outside of the window. This breaks up that reflection in the window and makes for a quick clean-up by simply spraying the window with a hose or waiting for the rain. Plus you’ve cleaned your windows!

Systematic semantics

What is the difference between a breed and a subspecies?

Thanks,

Andrew Coronado, Portland

This is a fun question because it gets into semantics around groupings of animals. Let’s break these down and get to the answer.

Perhaps it is best to start at the top. What is a species? The biological species concept says that a species is defined as a group of organisms that interbreed and produce viable young. There are lots of documented cases of hybrid species, which muddies the genetic pool and creates backcrosses. But let’s not get too distracted by what a species actually is, and stick to Andrew’s question. A subspecies is a taxonomic rank below species: a population of that larger group that is generally confined to a geographic region. In that geographic isolation, the population has less gene flow and may, over a very long time frame, start evolving unique traits. In theory, these isolated individuals could still breed with other members of their species across their whole range.

On the other hand, a breed is defined as a group of domestic animals that is selectively bred to accentuate a specific trait. So an important distinction is that breeds are typically brought about by human selection for a favored trait, where a subspecies is generally from a natural selection for a species in genetic isolation.

To pick an example, let’s use the familiar pigeon, which everyone has encountered on some city street. That rock pigeon (Colombia livia) is actually one of 13 recognized subspecies, from the nominate c. l. livia, which originated in the Western Palearctic (yes, despite their numbers, they are not native to North America). Each of those subspecies has a specific range they occur in. For example, if you were in India you’d see c. l. intermedia, and in the Canary Islands you’d see the appropriately named subspecies: c. l. canariensis.

Now within the subspecies c. l. domestica, you will find domestic breeds with bizarre traits that were selectively bred by humans. Pigeon breed names include, and certainly are not limited to: homing pigeon, fantail pigeon, old German owl pigeon, English pouter, helmet pigeon, and my favorite, the giant runt.

Do you have a nature question for Doug? Email questions to [email protected] and visit www.maineaudubon.org to learn more about virtual and backyard birding, online classes, and other programs about wildlife and habitat.