Northern Flicker Colaptes auratus Scientific name definitions

The Northern Flicker is a common, primarily ground-foraging woodpecker that occurs in most wooded regions of North America. Its frequent use of urban parks and bird feeders makes it a flashy visitor that may be observed and enjoyed even from the backyard. The taxonomic status of flickers in North America has been debated because of hybridization among subspecies groups, each readily distinguished by plumage coloration. Two subspecies, the Yellow-shafted Flicker (Colaptes auratus auratus) of eastern North America and the Red-shafted Flicker (C. a. cafer) of western North America, form a long, narrow hybrid zone in the Great Plains that parallels the rain shadow of the Rocky Mountains and crosses the Canadian Rockies extending to southern Alaska. This hybrid zone has been of great interest to ornithologists and evolutionary biologists for more than a century. Hybridization occurs on a more limited basis between the Northern Flicker and the Gilded Flicker (Colaptes chrysoides), which is associated with the Sonoran Desert.

The subspecies differ in several bright and contrasting plumage traits, the most obvious being the shaft color of flight feathers, from which two subspecies groups derive their common name. The bright yellow or red colors visible on the under surface of the wings are flashed at potential mates or rivals during courtship and territorial defense. Other traits that distinguish the subspecies are the presence of a bright red nuchal (nape) patch in the Yellow-shafted, Cuban (C. a. chrysocaulosus), and Grand Cayman (C. a. gundlachi) flickers (absent in other subspecies), and the color of the throat, ear coverts, crown, and malar stripe. The malar stripe is the only markedly dimorphic trait that distinguishes the sexes.

As its broad geographic distribution suggests, the Northern Flicker is a generalist in many respects, but in others it is a specialist. It is clearly a species of open woodlands, savannas, farmland with tree rows, and forest edges. It eats mostly ants but also a variety of other insect larvae and—during late autumn, winter, and early spring—a variety of berries. The species is well adapted to habitats altered by humans, commonly breeding in urban as well as suburban and rural environments. Nevertheless, data from the North American Breeding Bird Survey indicate declines in abundance, mainly for populations in the southeastern United States. Reasons for these declines are unclear, but possible explanations are habitat loss and competition with the European Starling (Sturnus vulgaris) for nest cavities. Although the Northern Flicker remains abundant, this declining trend should be viewed with concern because the Northern Flicker plays a central role as a "keystone species" in the ecology of woodland communities where it excavates many of the cavities later used by other hole-nesting species.

Early research on the Northern Flicker focused on phenotypic variation and dynamics of the hybrid zone. The detailed and descriptive work of Lester Short (1 Short, L. L. (1965). Hybridization in the flickers (Colaptes) of North America. Bulletin of the American Museum of Natural History 129:307–428. Close , 2 Short, L. L. (1967). Variation in Central American flickers. Wilson Bulletin 79:5–21. Close ), who studied flickers in the central United States, was followed by more quantitative models of dispersal, gene flow, and reproductive success of flickers in the hybrid zone (e.g., 3 Moore, W. S., and J. T. Price (1993). The nature of selection in the Northern Flicker hybrid zone and its implications for speciation theory. In Hybrid Zones and the Evolutionary Process (R. G. Harrison, Editor). Oxford University Press, Oxford, United Kingdom. pp. 196–225. Close , 4 Flockhart, T. D., and K. L. Wiebe (2009). Absence of reproductive consequences of hybridization in the northern portion of the Northern Flicker (Colaptes auratus) hybrid zone. Auk 126:351–358. Close ). Many researchers have reported on aspects of behavior and nest use by Northern Flicker as part of general studies of cavity-nesting birds. Such interest intensified after flickers were recognized as "keystone" excavators that influence the biodiversity and abundance of secondary cavity-nesting species in forest systems (5 Martin, K., K. E. H. Aitken, and K. L. Wiebe (2004). Nest sites and nest webs for cavity-nesting communities in interior British Columbia, Canada: Nest characteristics and niche partitioning. Condor 106(1):5–19. Close , 6 Drever, M C., K. E. H. Aitken, A. R. Norris, and K. Martin (2008). Woodpeckers as reliable indicators of bird richness, forest health and harvest. Biological Conservation 141:624–634. Close ). The largest study to date dedicated to understanding the reproductive ecology, life history, and population ecology of the Northern Flicker is a long-term study at Riske Creek in central British Columbia, where Karen L. Wiebe monitored 100–175 color-banded nesting pairs annually from 1997–2014. This study revealed the first known cases of polyandry in biparental woodpeckers in North America, and many details of an unusual breeding system with partly reversed sex roles where males contribute more to parental care than do females.