This article appeared in the Great Bend Tribune on Sunday, August 24 as part of the monthly KWEC column, The Wetland Explorer.

Let me introduce you to a new Scrabble word guaranteed to give you a win if you can pull it off…zugunruhe (pronounced zue-gun-rue). I’d venture to say that this is a word you have never heard before. So, what does this have to do with the Wetland Explorer? Zugunruhe is a German word that literally means movement anxiety. It is a term that biologists have used to describe the restless behavior of animals, especially birds, during and just before their migration. And, it is basically the phenomenon that causes birds to “know when to go.”

So, what causes zugunruhe in birds? Well, as is usually the case in biology, migration is a very complex behavior that involves many factors, and many scientists have studied deep into the physiology of migratory behaviors in many species. However, two factors are widely known to cause zugunruhe: day length and weather.

Many North American migratory birds spend their breeding seasons on northern breeding grounds, some even as far north as the Arctic Circle. We all know that day lengths during the summer months in northern latitudes are extremely long, which is a good thing if you are a bird finding food to raise your young. But towards the end of the summer, day lengths begin to dramatically shorten. This change in day length is a cue for birds to know it is time to head south.

Now, back to Kansas. Many of us living here do not realize that our wetlands start seeing the first southward migrants as early as July.  So, technically Fall migration starts then. These first arrivals are often adult birds that, for some reason, had failed nesting attempts up north and might have been too late to try to renest, so the birds get a jump on the other birds heading south to the wintering grounds.  The other birds will follow in due time. Fall migration is a drawn out process, extending from July through at least November. The birds are not in as big of hurry as they are during the Spring migration, with love on their minds.

Similar to the Spring migration, different bird species make their way to Cheyenne Bottoms at different times. There seem to be waves of birds coming and going so that the composition of birds at any one time changes week-to-week and even day-to-day. One of the best parts of working at the Wetlands Center is having the chance to observe this day-to-day change first hand.

In early July, we are seeing mostly the summer resident birds at Cheyenne Bottoms: herons, egrets, killdeer, grassland nesting birds, and a few other nesters. The first migrants to show up are typically yellowlegs, godwits, and a various sandpipers.  Shorebird migrant numbers will peak around the first week of August. Quivira National Wildlife Refuge has had excellent mudflats that have been loaded with shorebirds for the last few weeks. Later, blue-winged teal begin the waterfowl migration in late August followed by most other duck and goose species coming in in October and November. Cranes will mix in around October, as well as raptors and sparrows in the late Fall.

This progression of birds coming and going during their migration is what we call migration phenology.  Biologists and bird watchers will often document the first day particular species are seen each year during migration times. Over time, this information can provide a timeline for when we will expect particular species to be in our area.  Inevitably, the birds are right on time. Most years, bird species will arrive within a day or two of the historical median first day of observation.

Would you like to know when certain species are expected to show up at Cheyenne Bottoms throughout the year? This information is available to you. To access it, go to the Kansas Wildlife Parks and Tourism website at kdwpt.state.ks.us. In the search box, type Cheyenne Bottoms migration phenology, and you will find a link to the migration phenology of birds at Cheyenne Bottoms. Once you know when the birds will be here, find your own zugunruhe to get out to find them! The Kansas Wetlands Education Center would even be happy to take you out on a van tour to help you out. Come enjoy the Fall migration.