Red Crossbill

A regular but rare and erratic summer resident and migrant. The Red Crossbill was a rare species during the Minnesota Breeding Bird Atlas (MNBBA).

The Red Crossbill is found throughout coniferous forests and mountainous regions of the Holarctic, including North America, Europe, and Asia, with potentially many subspecies. The Red Crossbill’s breeding distribution is highly variable with highest recorded breeding densities in western mountainous regions of the United States and Canada, plus scattered populations in the upper Midwest, eastern Canada, and the northeastern United States (Figure 1).

Assigned a Continental Concern Score of 8/20 by Partners in Flight.

Permanent resident, nomadic.

Seeds, primarily spruce and pine; also seeds of many species of deciduous trees and some invertebrates in summer.

Cup-nest in coniferous trees, it is known to nest in any season of the year.

Roberts (1932) stated that the Red Crossbill is a permanent resident of Minnesota’s northern evergreen forests. He emphasized that “no nests have yet been reported from Minnesota though they certainly breed commonly in the northern part of the state.” He also described numerous observations of the Red Crossbill throughout the state from the late 1800s to the 1930s, especially in flocks. For instance, in 1871, Trippe found the species “very abundant; breeds” in the east-central part of the state. Barker reported that the crossbill was “quite numerous in the pine timber forty or fifty miles north of Parkers Prairie, Otter Tail County, and certainly breed there.” In August 1879, Roberts found the Red Crossbill common along the North Shore of Lake Superior from Duluth to Grand Marais, and in August 1922 the Surbers found the species generally distributed in Cook County, exclaiming crossbills to be present “literally” in swarms on the Caribou River.

Green and Janssen (1975) described the Red Crossbill as an irregular summer resident in the northern regions of Minnesota and its breeding distribution as basically the northern half of the state. The authors stated nesting had occurred as far south as Stillwater in Washington County. They included confirmed nesting from Clay County in 1967 (Johnson 1969) and inferred nesting in Cook, Crow Wing, and St. Louis Counties. They also underscored the importance of coniferous trees, which are essential to the species for both food and nesting.

Janssen (1987) further highlighted the Red Crossbill’s erratic nesting behavior because juveniles just out of the nest had been located in widely separated counties in the state, from Clearwater and Pennington in the northwest to Cook and St. Louis in the northeast, and south to Ramsey in the metropolitan area of the Twin Cities. Further highlighting the species’ seemingly vagabond nature, summer records existed from as far south as Cottonwood County in the southwest and Rice County in the south-central regions. Even though the more southerly records in the state may be nonbreeding birds, Janssen suggested that “sporadic nesting may occur.” He included confirmed nesting in Clearwater County since 1970, while Hertzel and Janssen (1998) only included confirmed nesting from Cook and St. Louis Counties since 1970.

The Minnesota Biological Survey (MBS) included 33 records of the Red Crossbill breeding season locations. The records were scattered between Clearwater County in the northwest, Otter Tail and Todd Counties in the west-central regions, and Cook County in the northeast (Minnesota Department of Natural Resources 2016). Many breeding locations were identified in between these areas, such as 3 in Hubbard County, 2 in extreme southwestern Beltrami County, 5 in Itasca County, and 3 in Lake County. The Red Crossbill likely occurs in Koochiching, northern Beltrami, and Lake of the Woods Counties, but these areas have not yet been covered by the MBS.

The MNBBA included 44 records of the Red Crossbill that were distributed primarily in the northeastern and north-central regions of the state (Figure 2). A total of 39 blocks had breeding records, including a new confirmed record for Lake of the Woods County (Figures 2 and 3; Table 1). Possible nesting was recorded at Camp Ripley in Cass County. The record noted three Red Crossbills seen by multiple observers on May 3, 2010, which were still present on June 5, 2010. Possible nesting was also recorded in widely scattered locations including 4 in Beltrami County, 1 record each in Cass, Hubbard, and Koochiching Counties, 3 in Itasca County, 14 in St. Louis County, 5 in Lake County, and 4 in Cook County. The species had too few observations to produce a reliable probability distribution map.

Changes in the historical distribution or abundance of the Red Crossbill are difficult to evaluate because of the lack of consistent data and its nomadic and erratic breeding behavior. In his review of this species in North America, Adkisson (1996) stated it may be extinct in Newfoundland and has declined in the state of New York and in northern New England “and probably elsewhere” after about 1910 due to logging. Historical nesting evidence in the southern portions of Minnesota is nonexistent, though Roberts (1932) reported many southern county observations during the summer months. Historical data are similarly vague in Michigan (Brewer et al. 1991), in Ontario (Cadman et al. 2007), and in Wisconsin (Cutright et al. 2006). In Wisconsin, the Red Crossbill was sporadically observed, but breeding evidence did not exist. Cutright et al. (2006) suggested that the current distribution “is certainly more widespread and frequent than past records show.” A definitive answer on whether the distribution or abundance of this species has changed in Minnesota remains inconclusive.

*Note that the definition of confirmed nesting of a species is different for Breeding Bird Atlas projects, including the definition used by the Minnesota Breeding Bird Atlas, compared with a more restrictive definition used by the Minnesota Ornithologists’ Union. For details see the Data Methods Section.

The Red Crossbill is highly associated with mature upland coniferous forests, especially those dominated by spruce, pine, and hemlock (Adkisson 1996). Little specific data exists for Minnesota, but Green (1995) emphasized a seed preference for white and red pine. The National Forest Bird Monitoring program (Niemi et al. 2016) rarely recorded the species; but when it was observed in late May to early July, it was almost exclusively in mature coniferous habitats such as red pine, jack pine, and lowland black spruce-tamarack cover types (Figure 4).

During their recent assessment on the conservation status of the Red Crossbill, Rosenberg et al. (2016) estimated a North American population of 7.8 million breeding adults. The species was not detected sufficiently in the MNBBA to reliably estimate a Minnesota population. The highly nomadic nature of this species also precludes any reasonable attempt to estimate a population.

The federal Breeding Bird Survey (BBS) analyses for Minnesota and most other states or regions were too unreliable to estimate a trend from 1966 to 2015 because of the small number of observations or routes in which the Red Crossbill was detected (Sauer et al. 2017). Adkisson (1996) also emphasized that population estimates within specific habitats were unreliable due to a paucity of data.

However, the BBS trend for all routes in the United Sates as a whole was reasonable and indicated a stable population from 1966 to 2015, although the species’ variability was very high in the early years of those counts (Figure 5). Overall, Partners in Flight (Rosenberg et al. 2016) estimated a population decline of 12% from 1970 to 2014.

A summary of Christmas Bird Count (CBC) trends from 1959 to 1988 provided a mixed signal in North America (Sauer et al. 1996). Survey-wide counts indicated no significant change in population over this time period and were consistent with population trends in Minnesota, Ontario, and Wisconsin. In contrast, many states in the northeastern United States south to North Carolina showed significantly declining numbers, while the wintering populations of many states in the West were increasing significantly. However, as with breeding bird trends, CBC data can be highly variable and must be interpreted with caution.

The Red Crossbill’s Continental Concern Score of 8/20 indicated little conservation attention because of the species’ large breeding distribution and population across the entire Holarctic region (Rosenberg et al. 2016). However, one subspecies in Newfoundland has been listed as endangered because of declining populations. The decline was potentially related to the loss of large-coned white and red pine due to forest fires and the introduction of red squirrels to the area (Environment Canada 2014).

Red Crossbill populations fluctuate substantially due to the patchy and varying productivity of the coniferous trees that provide its primary food sources (Reinekainen 1937). As Hahn (1995) suggested, this species has adapted to the extreme variability in its seed crop by evolving a nomadic wandering behavior, early onset of sexual maturity, and a long breeding season.

In general, little is known about factors affecting the Red Crossbill populations (Adkisson 1996). Habitat fragmentation in Finland resulted in a decline in its population, primarily because of shorter tree rotations and reductions of older forests (Helle and Järvinen 1986). Benkman (1993) reported similar population reductions with the loss of old-growth forests in the northwestern United States, because conifers greater than 60 years old produce the largest cone crops. In addition, Environment Canada (2014) suggested that extensive loss of pine trees in British Columbia and Alberta due to the mountain pine beetle will likely influence future Red Crossbill abundance in the region.

Adkisson (1996) emphasized the need to maintain increased rotation times and to set aside core tracts of old-growth forest across the species’ range in North America to maintain the various races of Red Crossbills. A better understanding of the genetics of these races is also a high priority. In its review of future changes in climate, Langham et al. (2015) and the National Audubon Society (2015) identified the Red Crossbill as “climate endangered” because of severe contractions in its summer and winter ranges in the Rocky Mountains of 64% and 77%, respectively, by 2080.