One constant about Mother Nature is change.
Over the last four or five decades, several species that once bred or wintered in the valley are now gone. The black terns that nested at the Hoover Ponds are gone. Burrowing owls that used to winter about the airport are also gone.
On the other hand, black phoebes, red-shouldered hawks and Anna’s hummingbirds are now well established as resident birds.
In just the last few years, another new species is gaining a foothold in the valley, purple martins. Martins are larger than the other swallows in North America. Unlike most swallows, male and females differ in appearance. The male is a uniform dark purple, while females have a gray collar and belly.
In many parts of the eastern United States, purple martins are welcome summer residents, with many towns and yards sporting multiroom boxes placed on poles just for martins, or dried gourds that have been hollowed out and hung for a nest.
I remember a shop project in middle school in Portland where I constructed a martin house. I had questions at the time. Martins were very rare in Oregon. In reality, the class was making nest boxes for house sparrows and starlings.
To see a purple martin in the state at that time, one usually needed to head for the coast. Scattered pairs nested in old pilings in the estuaries. I first saw them in Tillamook Bay and later along the lower Columbia and Florence.
Around the turn of the 20th century, purple martins apparently were more common in Oregon. They were found not only along the coast but also along the foothills of the Cascades and in the southern Willamette Valley. There were even a few places one could find purple martins breeding east of the Cascades in Klamath and Lake counties.
They typically used large, old snags for nesting. Some have speculated that with increasing timber harvest at the lower elevations, suitable snags for breeding became increasingly scarce and populations declined.
In the last 50 years, a sighting of a purple martin in the Rogue Valley was cause for birders to put on their binoculars and head out in the quest to see this rare bird. However, this appears to be changing.
In the last five years or so, the number of sightings has increased in the valley. Most sightings have centered around the Rogue River from Dodge Bridge to Gold Hill. I am unaware of any reports of nest locations, but I suspect they are nesting in dead limbs or snags of cottonwoods along the river. It’s just a matter of time before we find them. In the Willamette Valley they are again a regular breeding species.
The loss of nesting snags undoubtedly played a part in their decline in the early 20th century, but this seems an incomplete explanation for their decline and subsequent increase in abundance. I see no more potential nesting snags today than 50 years ago. While I cannot explain these changes, I am hoping that in the near future I can embark on another shop project and this time actually attract purple martins to a new condominium placed in my yard.
— Stewart Janes is a biology professor at Southern Oregon University. He can be reached at firstname.lastname@example.org.