Keith Porter: I need to know about the annual Christmas bird house what information is gathered.|||Prior to 1900, groups of hunters chose sides and competed to kill the most game in holiday "side hunts." Wildlife conservation was in its infancy at the turn of the century; wild birds were shot at will for home cooking, restaurants and the millinery trade. That set the stage for one of the first attempts to engage the public in conservation. It began on Christmas Day, 1900, when ornithologist Frank Chapman organized groups of birders to see who could identify, count and record the most species. Today the annual Christmas Bird Count (CBC) is the longest running citizen-science program in the world. CBCs provide a snapshot in time of winter bird populations. Information collected over many years is particularly valuable because it illuminates long-term population trends. CBC data is frequently used in peer reviewed scientific publications and has been used to link bird population declines to climate and habitat change. CBC data can even be used to illustrate trends in local bird populations. Using data from the last 50 years compiled by birder Jim Valimont, several trends become apparent. In 1960, for example, local counts reported no ring-billed gulls, no red-bellied woodpeckers, one Canada goose, four American robins, six Carolina wrens, 66 American crows, and 56 ring-necked pheasants. By 2008, counts for these species changed significantly: ring-billed gulls jumped to 583; red-bellied woodpeckers, 171; Canada goose, 1,415; robins, 1,020; Carolina wrens, 274; and crows, 10,260. Not a single pheasant has been reported since 2000. Urbanization, habitat destruction and climate change are just a few of the reasons for changes in bird populations. But absent long-term CBC data, these trends may have escaped detection completely.