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Fig. 4 | Evolution: Education and Outreach

Fig. 4

From: Diversifying Coevolution between Crossbills and Conifers

Fig. 4

Two examples of crossbill and conifer evolution and coevolution. a The distribution of Rocky Mountain lodgepole pine (black) and crossbills and cones in the Rocky Mountains (lower right), Cypress Hills (upper right), and South Hills and Albion Mountains (lower left). Representative sonograms of flight calls are shown for the South Hills crossbill (lower left) and the Rocky Mountain lodgepole pine crossbill (lower right; from Benkman 1999). Red squirrels (Tamiasciurus hudsonicus) are found throughout the range of Rocky Mountain lodgepole pine, except in some isolated mountains, including the Cypress Hills (CH), Sweetgrass Hills (SG), South Hills (SH), and Albion Mountains (AM). Red squirrels were absent from the Cypress Hills until they were introduced in 1950. b A white-winged crossbill (Loxia leucoptera leucoptera; upper left) and a Newfoundland crossbill (Loxia curvirostra percna; lower right), and representative partially closed and closed black spruce cones from the mainland (upper left) and Newfoundland (lower right; from Parchman and Benkman 2002). Red squirrels occur throughout the spruce forests of the mainland and were introduced onto Newfoundland in 1963. The inset in the upper right shows the number of red crossbills per party-hour observed during annual Christmas Bird Counts in Terra Nova National Park, Newfoundland from 1968 to 2005. A “party-hour” is one hour of observation by one group of observers

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