The Great Backyard Bird Count is an annual four-day event that engages bird watchers of all ages in counting birds to create a real-time snapshot of where the birds are across the continent. Anyone can participate, from beginning bird watchers to experts. It takes as little as 15 minutes on one day, or you can count for as long as you like each day of the event. It's free, fun, and easy-and it helps the birds."

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Carolina Wren's Shifting Range

Carolina Wrens are one of the most familiar and beloved birds of backyards in the eastern United States, especially in the southeastern states where they are most common [see figure 1]. Great Backyard Bird Count (GBBC) participants regularly report these perky and vocal birds. In states like Georgia, North Carolina, South Carolina, and Virginia, they are consistently among the top 10 most commonly reported species during the GBBC, and the species makes the top 20 in at least 8 other eastern states. Georgia reported 2,470 Carolina Wrens during GBBC 2002 with Atlanta, Georgia, reporting the most Carolina Wrens of any city, with 326 individuals tallied.

Figure 1

Figure 1 

Carolina Wrens are year-round residents, with pairs defending territories vigorously even in winter, making it unusual to see more than two individuals in a single backyard. The species is sensitive to extreme cold temperatures and to other severe weather events, and periodically, birds at the northern edge of their range edge show large die-offs that cause the species range to shift. Eventually, populations increase enough so that the range will move again northward. Christmas Bird Counts (CBC) have documented these die-offs and slow increases [see Figure 2 and 3, Great Lakes Region CBC maps from 1977 compared to 1992]. For example, total numbers of Carolina Wrens counted on Christmas Bird Counts declined by 50% from 1977 to 1978 and did not regain their former abundance until approximately 10 years later [see figures 4 and 5, CBC graph 1977-1988].
Figure 2

Figure 2

Figure 3

In the Canadian portion of their range, the numbers on Christmas Bird Counts dropped from 41 in 1977 to only 5 in 1978 but had increased again, to 256, by 1992 [Canadian CBC graphs 1977-1992].Figure 5

Figure 5Figure 6

Figure 6

What will this year's Great Backyard Bird Count data tell us about the distribution of Carolina Wrens? What will their numbers be like? We won't know unless you tell. Please help us document the population cycle of this fascinating species by participating in the Great Backyard Bird Count!