Changes in Species Range

The emerald ash borer is coming! The emerald ash borer is coming! The emerald ash borer has been in the news a lot recently, as it should be. This Asian insect showed up in Michigan in 2002 and has quickly spread to other states, leaving dead ash trees in its wake. Just this last spring it was documented in St. Paul, and it seems inevitable that it will expand its range into North Dakota soon.

We often hear about the spread of a species, usually associated with an introduced problem species such as the ash borer, zebra mussel, or tamarisk. But we need to remember that the range of our native species often change as well. I was reminded of that recently when the subject of pileated woodpeckers in the Turtle Mountains came up in a conversation.

Those crow sized woodpeckers showed up in the Turtle Mountains a few years ago. Historically their populations in North Dakota were largely confined to the Red River and its tributaries. Obviously their range has expanded, and there is little doubt the Turtle Mountains now have a small breeding population.

Pick up a bird guide and look at a range map of the peregrine falcon. Their breeding range is a long ways from Fargo, but now of course they are nesting right downtown. Mountain lions are expanding their range, and a small population of white faced ibis now summers around J. Clark Salyer National Wildlife Refuge.

There are more examples. Some of these species may be “coming back home,” and certainly some populations and species are on the decrease. What is obvious though, is that the ranges of species can change. They are dynamic. Documenting that change, however, can be difficult for a variety of reasons.

When it comes to birds it seems to be a lot easier. Amateur birders often provide scientists with important information about what is happening to bird populations and ranges. The Great Backyard Bird Count is a good example of that. On a more local scale, so is the North Dakota Game and Fish Department’s Winter Bird Count as well as the activities of the North Dakota Birding Society which maintains a website and discussion forum about birds and bird sightings.

Yes, a species range may change, and documenting that change may be difficult. But once those changes have been verified we may begin to address the more important question: why has the range changed!

Chuck Lura
Natural North Dakota is supported by NDSU Central Grasslands Research Extension Center and Dakota College at Bottineau, and by the members of Prairie Public. Thanks to Sunny 101.9 in Bottineau for their recording services.