Common Nighthawk (Chordeiles minor) Sarah Coury
Wyandotte, MI © Jerry Jourdan
At dusk and dawn over cities as well as open sections of the land, the Common Nighthawk can often be seen in its erratic, bat-like pursuit of insects on the wing. This member of the Distribution nightjar family is famous for the male’s Prior to the late 1890s when its numbers dramatic courtship displays in which it dives dropped significantly, probably because of within two meters (6.6 feet) of the ground and overhunting during migration through southern abruptly turns, flexing its wings to produce a states, the Common Nighthawk was thought to resounding boom as air rushes through the be fairly abundant and widespread in Michigan. primary feathers. Common Nighthawks lay By the middle of the twentieth century, the eggs directly onto bare, open surfaces such as species had recovered its “common” state status farm fields, beaches, prairies, rock outcrops, (Eastman 1991). Though general declines of parking lots, pine barrens and burned or cleared this species have been evident since the 1960s, patches of forest, and commonly will nest on the at the time of MBBA I, it maintained a wide flat gravel rooftops of cities and towns (Poulin distribution in Michigan, with reports from et al. 1996, Rasmussen 2006). almost every county.
During the breeding season, this species can be Since then its distribution has contracted found throughout Canada excepting the extreme considerably, with many counties statewide north, in all 48 continental U.S. states and reporting dwindling numbers. In eighteen of the patches of the interior and gulf coast of Mexico, LP counties where the bird was present during continuing locally through Central America. MBBA I, none were found during MBBA II, Though its winter range is yet to be well and in the extensively suburban region of the studied, it is thought to extend across much of southeast, Common Nighthawks seemed to have middle South America, giving the Common almost disappeared in seven counties which Nighthawk one of the longest migration routes were former hotspots. A likely explanation is of any North American bird (Poulin et al. 1996). the major land use changes that have occurred in During recent decades, numbers of this species that area between atlas periods. In Oakland have been steadily declining in Michigan and County from 1990-2000, for example, the throughout its expansive breeding range. It is, Michigan DNRE reported a 63% reduction in however, still considered a locally common agricultural land where the species may have summer resident in the state, and can be found previously nested, and an 84% increase in in many areas of both peninsulas. residential development (Oakes and Payne
© 2011 Kalamazoo Nature Center Common Nighthawk (Chordeiles minor) Sarah Coury
2005). The thumb area, southern and central Royale in the UP, Crawford and Oscoda counties of the LP showed a sparse distribution counties in the NLP and the SLP counties of of Common Nighthawks during MBBA I, which Wayne and Washtenaw. The difficulties has continued to contract since that time. Areas presented by efforts to obtain reliable data for of abundance in both MBBA periods were those this species include its elusiveness during featuring jack-pine plains, such as the north- daylight hours, absence of nesting material, central NLP and, scattered pockets across the camouflaged eggs and inaccessibility to rooftop UP, and around urban areas with a high density nesting sites, all of which may skew population of flat gravel roofs, such as Wayne and trend results. Washtenaw Counties in the eastern SLP. High proportions of the bird within regions featuring Conservation Needs these two habitat types were also noted in New Numerous factors may be contributing to the York, Wisconsin and Ontario accounts (Medler nationwide decline of Common Nighthawks. As 2008, Rasmussen 2006, Sandilands 2005). with all ground nesting birds, this species is highly susceptible to predation, especially by Breeding Biology domestic cats, and gulls and crows commonly In Michigan, Common Nighthawks arrive predate urban rooftop nests (Medler 2008). throughout May and breeding occurs primarily Wedgewood (1991) noted a correlation between in June (Eastman 1991). Females invariably lay the drop in Common Nighthawk populations two eggs directly onto a bare surface with no and the implementation of nonselective added nesting material, and incubate for 16-20 pesticide spraying programs for mosquitoes, as days (Poulin et al.1996). Males assume primary the bird’s diet consists entirely of insects. responsibility for feeding of the young via Decreasing city populations are probably due to regurgitation during the 17-18 days before they the ongoing transition from gravel to rubberized fledge (Poulin et al. 1996). From late August roofs, which are not used by the birds because through mid September, Common Nighthawks of their failure to provide a camouflage surface form flocks and begin their fall migration for adults and eggs alike, as well as their (Eastman 1991). tendency toward much hotter temperatures in the sun (Marzilli 1989). Abundance and Population Trends Breeding Bird Survey estimates for the Types of Common Nighthawk habitat loss Common Nighthawk in Michigan indicate a especially relevant in Michigan include statistically insignificant population decline of agricultural lands and jack-pine barrens. In the 0.6% per year from 1990-2007 (Sauer et al. southern LP, large areas of open cropland have 2008). During MBBA II, Common Nighthawks been lost to development and succession, as were found in a total of 350 atlas blocks (4.9%), small farming operations face uncertain down from 881 (12.4%) during MBBA I. Of financial futures (Sargent and Carter 1999). the 350 observations, 218 were “possible,” 121 Additionally in the north, fire suppression and were “probable,” and 11 – three from the an influx of invasive species has reduced the Detroit area and the rest scattered widely across area’s historically prevalent jack-pine barrens the state – were breeding confirmations. From (Sargent and Carter 1999). Management MBBA I to MBBA II, observations declined measures for this species that have proven from 219 to 136 in the UP, from 297 to 111 in successful include placing gravel pads in the NLP and from 365 to 103 in the SLP. Areas corners of flat, rubberized roofs (Marzilli 1989), with the highest counts were Chippewa, and maintaining open prairie and forest habitat Schoolcraft and Marquette counties and Isle through the use of prescribed burns.
© 2011 Kalamazoo Nature Center Common Nighthawk (Chordeiles minor) Sarah Coury
Sauer, J. R., J. E. Hines, and J. Fallon. 2008. Literature Cited The North American Breeding Bird Survey, Results and Analysis 1966 - 2007. Version Eastman, J. 1991. Common Nighthawk. In 5.15.2008. USGS Patuxent Wildlife Brewer, R., G.A. McPeek, and R.J. Adams, Research Center, Laurel, MD Jr. (eds.). 1991. The Atlas of Breeding Birds Wedgewood, J.A. 1991. Common Nighthawks of Michigan. Michigan State University in Saskatoon. Saskatchewan Natural Press, East Lansing, Michigan.. History Society, Regina. Marzilli, V. 1989. Up on the Roof. Maine Fish and Wildlife 31:25-29. Medler, M.D. 2008. Common Nighthawk. In McGowan, K.J., and K Corwin (eds.). 2008. The Second Atlas of Breeding Birds in New York State. Cornell University Press, Ithaca, NY. Oakes, J. and Payne, T. 2005. Worksheet for Establishing Deer Population Goals – DMU 063, Oakland County 2006-2010. Michigan Department of Natural Resources.
© 2011 Kalamazoo Nature Center