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Climate and Urbanization: Effects on Winter Birds

January 26, 2011

The range limits for different bird species are often changing, and recently many wintering birds have been shifting northward. The question is whether these range shifts are due to milder winter temperatures, or to an increase in bird feeding, which would allow species to survive in conditions that would normally be too harsh. Researchers from Project FeederWatch recently analyzed observations submitted by participants during the 2007-2008 season, focusing on eighteen common feeder species and incorporating information about urbanization, temperature, and precipitation for each count site.

A mixed flock gathers at a feeder in Oklahoma during heavy snowfall. Photo by Marquita Seifried.

It turns out that climate plays a critical role in shaping the range limits for many common feeder birds. Despite the presence of feeders throughout their range, several species did not persist throughout the winter in colder environments.  Weather also played a role, however, and many species were more likely to visit feeders more often during harsh weather conditions such as cold snaps.

Different species are also affected differently by factors such as urbanization. Some species are less likely to be found in urbanized areas, such as the Downy Woodpecker. Because these species are not adapted to urban environments, birds in more urbanized areas have a lower ability to tolerate very cold temperatures.

Downy Woodpecker by Gary Mueller.

Other species, such as the House Sparrow, demonstrate better adaptation to urban environments. For these species, urban areas act as refuges, allowing birds to tolerate colder temperatures.

House Sparrow by Raymond Belhumeur.

Check out the Project FeederWatch Map Room to see how the ranges for different species of feeder birds fluctuate over the years.

Source: Zuckerberg B., D. N. Bonter, W. M. Hochachka, W. D. Koenig, A. T. DeGaetano, and J. L. Dickinson. 2010. Climatic constraints on wintering bird distributions are modified by urbanization and weather. Journal of Animal Ecology.

  1. Sally permalink
    January 26, 2011 11:24 pm

    Thank you! I always wondered why I didn’t get house sparrows and now I know – my garden is not in a particularly urban area. And, I do get Downy Woodpeckers.

  2. dena permalink
    January 30, 2011 10:39 am

    I have noticed a big change over at my feeders this winter. Last year my normals were the sparrows, finches, juncos, male and female redbreasted nuthatch, male and female cardinal, male and female downys, Red-Bellied Woodpecker and perodically a Coopers Hawk sitting by the feeders and a Chickadee.
    This winter has seen major increases in Cardinals, Juncos, House and Yellow Finches, Chickadees. New to my feeders are the White-Breasted Nuthatches and Northern Flicker.
    Last year spotted a Red-Phase Eastern Screech Owl mating pair in one of the old maples surrounding my yard. Was able to get a few night pics of one of them and then a day picture while it was sleeping in in a tree cavity. Just this last week, one of them has been sitting on my shepards hook at dusk. Like clock work. In the morning I see one them on the power lines crossing my yard. Never seen them that much last year and didnt find their nest. The Downys have increased to be 2 pair now.
    I do live smack dab in the middle of a city and the only thing that I am doing different is making my own suet..


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