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Unusual Courtship Behaviors by Male American Woodcock
James B. Berdeen and David G. Krementz

Southeastern Naturalist, Volume 12, Issue 3 (2013): N1–N5

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Unusual Courtship Behaviors by Male American Woodcock James B. Berdeen1,* and David G. Krementz2 Abstract - Male Scolopax minor (American Woodcock ) occasionally perform courtship behaviors outside of the primary breeding period. The costs and benefits of such behaviors are not known. We observed a Woodcock perform an aerial courtship display in Minnesota on 8 November 2010, a juvenile male emit peent vocalizations in Virginia on 12 December 1991, and a solitary individual emit a cackle vocalization in Georgia on 28 December 1994. These behaviors may have been aberrations that are selected against and therefore uncommon, influenced by environmental conditions, or performed to improve the quality of male courtship behaviors. Research and monitoring are needed to ascertain which if any of these explanations is corre ct. Introduction. Scolopax minor Gmelin (American Woodcock) is a polygynous species (Keppie and Whiting 1994) in which males perform courtship behaviors predominantly in open habitats during morning and evening crepuscular periods (e.g., Sheldon 1971, Tappe et al. 1989). These behaviors include a 5-part aerial courtship display in which: (1) the initial flight from the ground occurs; (2) the flight trajectory gradually slopes upward in a regular spiral pattern and wing beats become audible and increase in pitch; (3) the greatest increase in altitude occurs and the wing twittering initially is pulsated but the wing pulse becomes quick and increasingly audible near the apex of the flight; (4) the flight path becomes irregular as the greatest altitude is attained, and there are slight decreases and increases in altitude, intermittent wing twittering and vocal chirping occurs, and then a decrease in altitude begins; and (5) the decrease in altitude becomes abrupt and the flight is silent until there is a barely audible flapping of the wings as the bird slows to land (Keppie and Whiting 1994, Pitelka 1943). Males emit a soft gurgling vocalization (i.e., tuko) and a mechanical buzzing vocalization (i.e., peent) before and after courtship flights (Keppie and Whiting 1994, Sheldon 1971). Males also emit a hoarse buzzing vocalization (i.e., cackle; Sheldon 1971) that usually is given when one flying male chases another from its courtship display site, but also by one flying bird circling or hovering over another that is on the ground and producing a peent vocalization, and by males on the ground (Keppie and Whiting 1994). This vocalization also is emitted in diurnal habitat immediately before flying to courtship sites, and when males make circular flights over short vegetation, perform courtship displays, and land after courtship flights (Pitelka 1943). Although classified as an agonistic behavior (Sheldon 1971), the cackle vocalization is associated with the territories in which courtship displays occur and is directed toward competing and intruding males (Pitelka 1943). Consequently, we consider the cackle vocalization to be indirectly associated with courtship. Courtship displays and peent and cackle vocalizations have been observed on both the breeding and wintering grounds, but there appears to be substantial variation in the frequency with which these behaviors occur throughout the annual cycle. Specifically, courtship behaviors have been observed most frequently on the breeding grounds from the birds’ arrival in early spring until mid-May (Liscinsky 1972) or early June (Dwyer 1Minnesota Department of Natural Resources, Wetland Wildlife Populations and Research Group, 102 23rd Street NE, Bemidji, MN 56601. 2US Geological Survey, Arkansas Cooperative Fish and Wildlife Research Unit, Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701. *Corresponding author - james.berdeen@gmail.com. Notes of the Southeastern Naturalist, Issue 12/3, 2013 N1 2013 Southeastern Naturalist Notes Vol. 12, No. 3 N2 J.B. Berdeen and D.G. Krementz et al. 1988), and have been detected only occasionally during the summer and fall (Liscinsky 1972, Mendall and Alduous 1943, Pettingill 1936, Sheldon 1971). Courtship displays have been observed as late as December in eastern Massachusetts (Sheldon 1971). Similarly, courtship displays on the wintering grounds were observed as early as mid-November in Alabama (Roboski and Causey 1981), but peaked during mid-to-late February and were not detected after 15 March in Texas (Whiting and Boggus 1982). Cackle vocalizations have been most commonly observed during the early spring on the breeding grounds (Sheldon 1971) but also on the wintering grounds (T. Roberts, Tennessee Technological University, Cookeville, TN, pers. comm.). The benefits of performing courtship behaviors outside of the primary breeding period (i.e., any time other than March–May; Keppie and Whiting 1994) are not understood, but costs likely exist (e.g., exposure to predators, energy expenditure). We describe three observations of American Woodcock performing unusual courtship behaviors during the fall and winter, and provide explanations for the potential costs and benefits of these behaviors. Observations. The first observation was an aural detection of parts (3) and (4) of a courtship display at 1739 CST on 8 November 2010 near Turtle River, Beltrami County, MN (47°39'31"N, 94°47'50"W). We did not visually observe this bird or aurally detect a peent vocalization. Times of sunset, moonrise, and moonset were 1651, 1016, and 1836 CST, respectively, at Turtle River on the date of observation (US Naval Observatory 2011a). The moon phase was waxing crescent and 0.08 illuminated (US Naval Observatory 2011b). The air temperature was 7.1 °C and barometric pressure was 1005 hPa and rising at the nearest weather station (Bemidji, MN) on the date and time of observation (Weather Underground 2012). The average high and low temperatures at Bemidji on this date were 3.3 °C and -6.1°C, respectively, but actual high and low temperatures were 13.9 °C and 2.8 °C, respectively (Weather Underground 2012). The temperature in north-central Minnesota during November 2010 was greater than the 1890–2010 mean for that month (Western Regional Climate Center 2011). The second observation was a juvenile male American Woodcock emitting peent vocalizations near Cape Charles, Northampton County, VA (37°07'46"N, 75°57'49"W) from 1705–1716 EST on 12 December 1991 (G. Sepik, US Fish and Wildlife Service, Baring, ME, pers. comm.). The age and sex of this individual were ascertained using feather characteristics (Martin 1964) after its capture. Times of sunset, moonrise, and moonset were 1647, 1109, and 2251 EST, respectively, at Cape Charles, VA on the date of observation (US Naval Observatory 2011b). The moon phase was waxing crescent and 0.34 illuminated (US Naval Observatory 2011a). The air temperature was 11.7 °C, and barometric pressure was 1026 hPa and rising at 1700 EST at the nearest weather station (Cape Charles, VA) on the date of observation (Weather Underground 2012). The average high and low temperatures at Cape Charles on this date were 11.1 °C and 2.8 °C, respectively, but actual high and low temperatures were 12.8 °C and 2.8 °C, respectively (Weather Underground 2012). The temperature in southeastern Virginia during December 1991 was greater than the 1890–1991 mean for that month (Western Regional Climate Center 2012a). The third observation was a visual detection of an American Woodcock flying from a bottomland hardwood swamp into a regenerating clearcut near Eatonton, Putnam County, GA (33°26'19"N, 83°28'24"W), followed by an aural detection of a cackle vocalization emitted by this individual at 1756 EST on 28 December 1994. This was the N3 2013 Southeastern Naturalist Notes Vol. 12, No. 3 J.B. Berdeen and D.G. Krementz first American Woodcock detected during the crepuscular period, and its cackle vocalization was emitted before the first courtship display had been performed. We did not detect another conspecific during or immediately after this observation, but observed one individual aerially chasing another and emitting a cackle vocalization at 1811 EST. This observation is most similar to Pitelka’s (1943) description of a bird making a circular flight over short vegetation. Times of sunset, moonrise, and moonset were 1734, 0317, and 1415 EST, respectively, at Eatonton, GA (US Naval Observatory 2011b). The moon phase was waning crescent and 0.19 illuminated (US Naval Observatory 2011a). The air temperature was 15.0 °C and barometric pressure was 1018 hPa and rising at 1800 EST at the nearest weather station (Athens, GA) on the date of observation (Weather Underground 2012). The average high and low temperatures at Athens on this date were 12.2 °C and 0.6 °C, respectively, but actual high and low temperatures were 20.6 °C and 1.1 °C, respectively (Weather Underground 2012). The temperature in central Georgia during December 1994 was greater than the 1890–1994 mean for that month (Western Regional Climate Center 2012b). Discussion. The performance of a courtship display in Minnesota was unusual because it occurred when there were likely relatively few American Woodcock present in Beltrami and nearby counties (Myatt and Krementz 2007) and is one of the most northerly reports of this behavior occurring during the fall. The only other similar observation at approximately the same or higher latitude occurred at approximately 47oN in New Brunswick (D. Keppie, University of New Brunswick, Fredericton, NB, pers. comm.). The observation from Virginia is the earliest documentation of a juvenile male emitting a peent vocalization during the winter of which we are aware. The cackle vocalization in Georgia is 1 of 2 documentations of such a behavior occurring when no other conspecifics were detected concurrently. Such observations are interesting because similar behaviors have rarely been documented during decades of research. We offer 3 potential explanations why such behaviors were performed during portions of the annual cycle in which little or no breeding likely occurred. First, courtship behaviors performed during the fall and early winter may be aberrations that are selected against and thus less common than during the spring. Second, environmental conditions may have influenced the performance of courtship behaviors (Pitelka 1943). Specifically, warm temperatures have been associated with relatively late dates of fall migration (Keppie and Whiting 1994), gonadal development (Mason et al. 1982, Olinde and Prickett 1991), and the “onset and extent of breeding” (Roberts 1993). Lunar phase and barometric pressure may have influenced migratory behaviors (Krementz et al. 1994, Meunier et al. 2008), but the effect of either variable on male courtship behaviors is not well understood. The relatively warm conditions in Minnesota likely encouraged some individuals to remain at a high latitude relatively late during the fall, but research is needed to understand the effects of the sparsely illuminated moon and changing barometric pressure on courtship behaviors. Third, males may have been performing courtship behaviors before the primary breeding period to improve the quality of such displays and ultimately their reproductive success. Because female American Woodcock are thought to select mates based on the aerial maneuverability exhibited during male courtship displays (Johnsgard 1994), it follows that the quality of such displays would be positively associated with male reproductive fitness. Given that: testicular recrudescence begins in December (Stamps and Doerr 1977, Whiting and Boggus 1982), follicular recrudescence begins in early January (Whiting and Boggus 1982), and the earliest nesting 2013 Southeastern Naturalist Notes Vol. 12, No. 3 N4 J.B. Berdeen and D.G. Krementz occurs in late January (Causey 1981), it is unlikely that a courtship display performed in November or peent vocalizations emitted in December would result immediately in copulation with a fecund female. Similarly, a cackle vocalization emitted in an opening during December probably would not prevent male competitors from courting and accessing females at that site. The performance of courtship behaviors outside of the primary breeding period would be warranted if the benefits (e.g., relatively high lifetime reproductive success attributable to such behaviors) accrued were greater than associated costs (e.g., a relatively low probability of survival caused by energy expenditure or exposure to predators). Although there is no information about the lifetime reproductive success of American Woodcock (Keppie and Whiting 1994), the probability of individual adult and juvenile males surviving multiple breeding seasons is low (i.e., mean life spans of these cohorts are 1.31 and 0.91 y, respectively; calculated from annual survival rate estimates of birds banded in the north-central US [Mayhew and Luukkonen 2010] using the Anderson [1975] method). Thus, it may be advantageous for males to improve the quality of their courtship behaviors relatively early in life to increase their lifetime reproductive success. Determining which of our explanations is correct may require knowledge of the extent to which individuals perform courtship behaviors during the nonbreeding period and the costs and benefits of performing these behaviors. Gaining such knowledge could be accomplished by monitoring the level of courtship behaviors outside of the primary breeding season across individual males and relating those levels to survival and reproductive success, and by determining whether courtship behaviors outside of the primary breeding season are related to environmental conditions. Acknowledgments. Funding for the portion of the project conducted in Georgia was provided by The Ruffed Grouse Society, US Fish and Wildlife Service, US Geological Survey Patuxent Wildlife Research Center, Georgia Ornithological Society, and the University of Georgia. Warnell School of Forest Resources granted access to their property. G. Sepik (US Fish and Wildlife Service, deceased) assisted with field research in Virginia and provided information about the second observation. D. Keppie and T. Roberts provided information about fall and winter courtship behaviors of American Woodcock. D. Keppie, D. McAuley, and an anonymous reviewer provided helpful comments on earlier versions of this manuscript. Literature Cited Anderson, D.R. 1975. Population ecology of the Mallard. V. Temporal and geographic estimates of survival, recovery, and harvest rates. US Department of Interior, Fish and Wildlife Service, Research Publication 125, Washington, DC. 110 pp. Causey, M.K. 1981. Alabama Woodcock investigations: Study II. Final report, P-R project W-44-5. Alabama Department of Conservation and Natural Resources, Montgomery, AL. 22 pp. Dwyer, T.J., G.F. Sepik, E.L. Derleth, and D.G. McAuley. 1988. Demographics of a Maine Woodcock population and effects of habitat management. 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