Geographic Range. Evidence suggests breeding of this form from the Atlantic Provinces of Canada westward through the northern Great Lakes region and into vast areas of Northern and western North America, where it reaches its greatest abundance. Although recordings of this form are not available from most areas, museum specimens indicate a breeding range reaching northward to northern Alberta and southern Alaska. There is currently no evidence for breeding of this form in the Sierra Nevada, even though Douglas fir (Pseudotsuga menziesii, a tree with which it is strongly associated) is common there.
Ecology and Habitat. This medium sized crossbill is not generally associated with thick-coned pines. In the East, this crossbill probaly associated strongly with spruce (Picea), hemlock (Tsuga) and white pine (Pinus strobus). Throughout the West, most observations of this forms suggest a strong association with Douglas fir (Pseudotsuga menziesii).
Natural History Notes. This form is nearly identical to Type 1 in overall size. However, these two forms apparently have ecological differences, such that Type 4 is far more common than Type 1 in many areas such as the Pacific Northwest. The relative abundance of Type 4 crossbills in eastern forests is not known.
Vocalizations. Toop calls of Type 4 are almost inseparable from Type 2 toops, even with audiospectrographic analysis.