I’ve been doing a little research that caught my attention.

The town of Medford is home to about 78,000 people — large enough that I hear people complain of the traffic from time to time. But compared to the cities across Oregon, it’s not especially large. On the national scale, it’s hardly noticeable. On a worldwide scale, we are nearly invisible.

Yet the world population of a large number of bird species is less than the population of Medford. These include a number of species easily observed in our region and not considered threatened. If you wish to see a few black oystercatchers with their almost comical large, red bills, head for the coast and you can almost guarantee seeing a pair or family as they scour the barnacle-covered rocks at low tide. Yet wildlife biologists put their number as barely more than 10,000 individuals stretching from the Aleutian Islands to Baja.

A trip to the wildlife refuges in the Klamath Basin in spring is likely to produce one or more long-billed curlews with their outrageously long bills. Their bills are better suited to probing mudflats along the coast in winter than nabbing grasshoppers and other insects from the grasslands east of the Cascades. The world population is estimated to be about 20,000.

If you take an afternoon birding trip to the White City area or Agate Lake in winter, the chances are better than even that you will find a large pale hawk with a rusty-colored back perched on a utility pole. This ferruginous hawk represents one of only 23,000 individuals spread across western North America. These three species taken together still don’t total up to Medford’s population.

A pelagic trip off the Southern Oregon coast in August will produce a number of species gathered here either in migration or spending the summer. Among these will be the pink-footed shearwaters that breed on Robinson Crusoe Island and a couple of others off the coast of Chile. The world population is estimated to be 60,000 individuals. It’s a big ocean, and it amazes me that they can be found so easily off our shores. Observing 100 of them in a day is not unusual and makes it difficult to conceive just how few of them there are.

The list of those whose total numbers are smaller than the population of Medford continues with surfbirds, elegant terns, yellow rails and the North American subspecies of whimbrel — and those are just in our region. Threatened and endangered species are much rarer still. Conversely, the number of species in North America that have populations that top 10,000,000 individuals is surprisingly small.

The modest numbers of so many species, including some we consider common, makes me realize the vulnerability of much of our wildlife. On one level I have been aware of the limited populations of many species, but I had never before considered these numbers in light of the population of my hometown. It somehow makes these numbers more real and at the same time reminds me of the need to be good stewards of the biodiversity in our region.

— Stewart Janes is a biology professor at Southern Oregon University. He can be reached at janes@sou.edu.