|Most Numerous Species||Summary by Species||Summary by Year|
Quite a few species whose winter ranges once ended just south of us are now
being seen more regularly or in larger numbers on the count. This trend is more
likely due to a change in seasonal distributions than to population increases.
Good examples are ..
Great Blue Herons,
Fox Sparrow, and
West Nile VirusAmerican Crows suffered a dramatic decrease in 2002 which corresponds to the arrival of the West Nile virus in northern Illinois.
Pheasants and CoyotesRing-necked Pheasants have undergone a gradual decline since the mid nineties. This is probably due to an increase in local coyote populations which occurred at about the same time.
Canada Geese dramatically increased their numbers through the eighties to become the most abundant species in the count circle. Since then the numbers have remained stable despite large year to year fluctuations.
Cooper's Hawk numbers have increased dramatically since the early nineties. This reflects increased numbers throughout the year.
The House Finch InvasionPurple Finches declined sharply in the late eighties this is about the time when the closely related House Finches expanded its range into the region.