Part of the draw of bird watching is the thrill of finding birds that are not typical for your location. Some years produce more rarities than others. This winter is proving to be a pretty good year.
For several species of birds, ornithologists have labeled this winter an irruption year. An irruption is when there are irregular migrations of large numbers of birds to an area where they typically are not common. It is quite typical to have one or two vagrant birds show up in Kansas in any given year that are not typically here. However, during irruption years, unusually high numbers of these vagrants can be spotted.
Irruptions can be caused by several different environmental factors, such as a lack of food, harsh weather conditions, or overpopulation in the bird’s typical range. Several different species are known to irrupt in different years, but most irrupting species are northern and/or boreal bird species.
Right now in central Kansas, two unique species are being closely watched as irruptive candidates: snowy owls and red crossbills.
Snowy owls are one of the most recognizable and majestic birds of North America. About the same size as a Great-horned owl but bright white in color, these owls of the Arctic occasionally venture south during the winter months. Typically, Kansas birdwatchers will report a couple snowy owls each winter. So far, this winter, there have been at least 30 snowy owl reports in 20 different Kansas counties. As early reports of snowy owls showing up in northern states began as early as October, bird enthusiasts prepared for a potentially good viewing year.
In the past, most believed that snowy owls, who feed primarily on lemmings, a small rodent in the Arctic, are forced south in search of food during years when the lemming population crashes. However, more recent discussions indicate that the opposite may be true in that large lemming populations during the summer breeding months have produced an abundance of owls who venture south in search of space.
Some may remember the last snowy owl irruption in the winter of 2011-2012. During that year there were approximately 150 confirmed snowy owl sightings across Kansas. The Kansas Ornithological Society worked to keep track of the sightings. Another irruption year in Kansas was in the winter of 1974-1975, when 81 snowy owls were reported.
This winter, another bird species is irrupting throughout the central U.S. Red crossbills are a small song bird typically at home in the coniferous forests of Canada, the Rocky Mountains, and the Pacific Northwest. As their name implies, their upper and lower beaks are crossed in an x shape, which it uses to pry open tightly closed pine cones to find conifer seeds, which are its only diet. Typically, crossbills are observed in small flocks. Similar to snowy owls, it is believed that a very successful breeding year by crossbills has resulted in large flocks spanning further south into areas that they typically are quite scarce.
In Kansas, flocks of crossbills began showing up in isolated pine tree stands in August in several counties. Now, red crossbill flocks have been reported in at least 29 different counties across Kansas. The last crossbill irruption was seen in the winter of 2012.
Barton County has seen both snowy owls and red crossbills this winter. During the Cheyenne Bottoms Christmas Bird Count this past week, both species were documented. As I write this article, there are reports of possibly three snowy owls at Cheyenne Bottoms.
As with most wildlife sightings, the only way to take part in the thrill of seeing them is to get outside and look for them. If you are interested in seeing these rare species, irruption years are the times to see them. Take advantage of the opportunities to search for these and other species. You never know when they may be gone!