The Duluth News Tribune reports the likely cause of the reduced numbers has to do with back-to-back cold, late springs. Fewer chicks hatched this year may also likely mean fewer birds returning to be counted next year.
The 20th annual Summary of Breeding Bird Trends was released by the Natural Resources Research Institute at the University of Minnesota Duluth. The bird count stood at nearly 20,000 in 2009, but crashed to 12,500 this year.
The survey sends researchers to predetermined locations in the forest to tally birds by their sound. Researchers note there has been an upward trend in many forest bird species during the past two decades, prior to this recent weather-related decline.
Even with 2014’s drop, most of the 73 species counted are doing well. About 37 percent have increased and 40 percent are stable; 23 percent of the species are declining at a significant rate.
Climate and habitat changes may also contribute to the decline in forest bird populations, due to changes along migration routes and in the birds’ wintering areas. Earlier this year, a report by the National Audubon Society found that the Common Loon may no longer be heard in Minnesota by the year 2080. Audubon climate models show that the warming atmosphere threatens Minnesota's state bird.
Bird counts by volunteers are common throughout the state. The Walker Pilot-Indendant put out the call for volunteers to take part in the annual winter bird count at Itasca State Park on Dec. 14. It was the park’s 20th year of participation in the nationwide Audubon Christmas Bird Count, used to track migration patterns and changes in winter bird species.