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Northern Pintail

Anas acuta

Order:
Anseriformes
Family:
Anatidae
Sections

Demography and Populations

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Figure 5. Northern Pintail breeding population estimates

Northern Pintail breeding population estimates by region, 1955–1994, based on data from annual May breeding waterfowl surveys (U.S. Fish and Wildl. Serv. unpubl. data).

Measures of Breeding Activity

Age At First Breeding; Intervals Between Breeding

Both males and females can breed at 1 yr of age, but some immature males may not because of excess males in the population. Breeds annually but may skip years when habitats are dry.

Clutch Size And Renesting

Reported clutch size is smaller than that of most North American dabbling and diving ducks. Average clutch size in prairie grassland area ranges from 6.9 – 7.6 eggs (n = 1,267 nests; Keith 1961, Duncan 1987b) Guyn and Clark 2000, Krapu et al. 2004; Colorado 7.0 (n = 212; Colorado Dep. Nat. Resour. unpubl. data); Alaska 7.5 – 7.6 (n = 888; Petrula 1994, Flint and Grand 1996a); California 7.8 (n = 615; Hunt and Naylor 1955, Rienecker and Anderson 1960, A. Perkins and R. McLandress pers. comm.); Utah 7.8 (n = 196; Williams and Marshall 1938, Fuller 1953); and prairie parkland 8.0 (n = 216; Sowls 1955, Stoudt 1971).

Northern Pintails in Alaska, s. Alberta, and N. Dakota are capable of laying 10- to 12-egg clutches in first nests (Duncan 1987b, J. B. Grand and G. Krapu pers. comm.); averages reported above are lower because most studies outside Alaska commence after first 1–2 wk of nesting period, when clutches are largest, and because of high losses of early nests before full clutches are achieved.

In s. Alberta, clutch size of adults (>2 yr old) declines with laying date until end of May, then levels off in early June (Duncan 1987b, Guyn and Clark 2000). When adjusted for laying date, clutches of adults are larger than those of yearlings. Overall, proximate factors affecting clutch size are female age, environmental conditions, and individual variation (Duncan 1987b). In the prairies, the predicted decline in clutch size over the nesting season is about 3 eggs, with the rate of decline not directly related to increases in day length (Krapu et al. 2002). On the Yukon-Kuskokwim Delta (Y-K Delta) in Alaska, clutch size declined during the 44 – 47 day nesting interval at a greater rate than reported for other populations of Northern Pintails (Flint and Grand 1996a).

Renesting after loss of nest seems related to availability and stability of wetlands. Proportion of adults renesting is greatest in years of good wetland conditions, low to nonexistent in years of dry conditions; possibly there is individual variation in renesting persistency (Duncan 1987b). Yearlings seem to have low propensity to renest (Duncan 1987b). In s. Manitoba, Sowls (Sowls 1955) found that 30% of marked females renested. In central N. Dakota, 8 of 14 Northern Pintails (56%) collected after mid-May showed evidence of renesting (G. L. Krapu pers. comm.). On the Yukon-Kuskokwim Delta, AK, 28% of collected hens showed evidence of renesting (D. Esler and J. B. Grand pers. comm.) 56% (n=39) of radio-marked females renested at least once, propensity to renest declined among females that initiated later first nests, and mean renesting interval was similar between first and second nests and second and third nests (11.3 – 11.4 days) (Grand and Flint 1996b). In contrast, renesting is uncommon in se. Alberta despite low nest success and also low in California; may be related to poorer water permanency in these regions (Duncan 1987b, R. McLandress pers. comm.). Collection of 2 females arriving in Alaska that had already laid eggs (based on ovulated follicles) suggests that some individuals may renest in northern breeding areas after failed nesting efforts farther south (J. B. Grand pers. comm.). In a grassland- dominated landscape in southern Alberta, renesting of radio-marked females was 55% from a sample of 20 decoy-trapped females to 85% from 13 nest-trapped hens (Guyn and Clark 2000). No documentation of >3 nesting attempts/hen for Northern Pintails. Radio-marked pintails trapped on nests in a cropland-dominated area of se. Saskatchewan exhibited similar renesting rates (61 – 90%), with renesting propensity declining seasonally with few renesting twice (37%) and even fewer 3 times (7%) (Richkus 2002).

Annual Reproductive Success

Varies greatly over the breeding range, depending primarily on nest success (proportion of nests that produce one or more ducklings) and duckling survival rates. Nesting effort (whether a hen attempts to nest in a year and how often she will renest) probably is also a significant factor.

Nest Success. Highly variable among years, areas, and habitats, owing largely to predation and variable weather conditions. In Alaska, 1991–1993, 0–43% of nests hatched young (Petrula 1994, Flint and Grand 1996a); in Canadian prairies, 1982–1985, 0–31% (R. J. Greenwood pers. comm.); in California, 1985–1989, 16–75%; A. Perkins and R. McLandress pers. comm.).

In Yukon-Kuskokwim Delta, AK, nest success averaged 24% (1991–1993, n = 795; Flint and Grand 1996a); in interior Alaska, only 3.8% (1991–1993, n = 120; Petrula 1994). Nest losses due largely to predation and, along coastal Alaska, to tidal flooding (Flint and Grand 1996a).

In an extensive evaluation of nesting in the Prairie Pothole Region (PPR) of U.S., nest success did not differ between 1966–1974, 1975–1979, and 1980–1984 but did differ among states (Klett et al. 1988). By habitat, success was highest in idle grassland (18–27%), grassland (10–19%), and planted cover (9–10%); lowest in cropland (5–11%), hayland (2–4%), rights-of-way (6–9%), and wetlands (5–8%). Another extensive evaluation of nesting pintails (n = 929) in the PPR of Canada from 1997 – 2009 revealed variation in nest success by habitat with the highest estimates from fall-seeded cropland (winter wheat and fall rye) (25 – 47%), idle grassland (15 – 33%), and hayland (12 – 29%); and lowest in grazed grassland (9 – 21%), spring cropland (4 – 15%) and wetland edges (1- 13%) (J. H. Devries, DU Canada, pers. comm.). In s. Alberta, nest success varied annually but was consistently higher in grassland-dominated than cropland-dominated landscapes (Kowalchuk 2012).

In the Canadian Prairie Pothole Region during 1982–1985, mean nest success was low (7%; Greenwood et al. 1995a) and varied widely among areas and years (0–31%, n = 762; R. Greenwood pers. comm.). Unsuccessful Northern Pintail nests were lost primarily to predation (71%), a percentage similar to that of other upland-nesting Anas species, but agricultural tillage accounted for a higher proportion of nest losses (17%) in Northern Pintails than in other species. In contrast to this low rate of nest success in intensively farmed prairie (averaging 59% cropland), Duncan (Duncan 1987a) found high nest success (64%; n = 33) on a large (>19,000 ha) area of unbroken, grazed prairie in se. Alberta. But in similar areas of s. Alberta, Guyn and Clark (2000) reported lower nest success (6 – 18%), except on islands in managed wetlands (53 – 68%).

Hatching Success. Percentage of egg loss to infertility and embryo death is relatively low (≤7%; Fuller 1953, Rienecker and Anderson 1960, A. Perkins and R. McLandress pers. comm.).

Brood and Duckling Survival. Major sources of mortality include predation and exposure to severe weather; most losses occur within first 2 wk of hatching (Duncan 1986d, Grand and Flint 1996a). Survival of ducklings on the Yukon-Kuskokwim Delta, AK, was lower than reported elsewhere and differed among years (3.96–14.47%, n = 770 ducklings, 111 broods, 1991–1993; Grand and Flint 1996a). Survival rates decline with hatching date at 0.6%/d. Brood size at hatch averaged 6.9 ducklings and brood survival ranged from 17.6% - 45.5% (Grand and Flint 1996a). Brood survival in s. Alberta on managed wetlands was much higher (72 – 88%) and declined with hatch date (Guyn and Clark 1999). Duckling survival from the same study was similar to that reported for prairie nesting mallards, ranging from 42 – 65%. Similar to AK, most mortality occurred during the first 10 d after hatch, and did not vary with female age or distance from nest to nearest wetland (Guyn and Clark 1999). Conversely, pintails studied in a cropland-dominated landscape in Saskatchewan, had lower brood and duckling survival, 46% and 29%, respectively (Peterson 1999).

Estimates of Productivity. Common variables used in assessments of annual waterfowl productivity include nest success (discussed above), hen success (proportion of hens that hatch a clutch), and number of young ducks fledged/breeding pair. Although hen success has not been directly measured, Flint and Grand (1996a) estimated hen success of 37.8% for the Y-K Delta, AK., and no reliable measure of productivity (number of fledged juveniles/breeding pair) is available other than age ratio in harvest (see also Population Regulation). Flint et al. (1998) modeled productivity and found that adult survival had the greatest influence on population growth rate (based on data from the Yukon-Kuskokwim Delta, AK); furthermore, all young in the population were produced by 13% of the breeding females, and early -nesting females produced the most young.

Calverley and Boag (Calverley and Boag 1977) theorized that the reproductive potential of arctic-nesting Northern Pintails was lower than that of prairie-nesting individuals owing to lower nesting effort, smaller clutch size, and lack of renesting. Recent studies of Northern Pintails in AK, however, indicate that most females attempt to nest, clutch sizes are similar to those reported from the prairie, and renesting occurs (Flint and Grand 1996a, Grand and Flint 1996a,b); however, there are insufficient data to compare nesting effort between AK- and prairie-nesting birds. Flint and Grand (1996a) concluded that pintails nesting in the Yukon-Kuskokwim Delta are at least as productive as their prairie nesting counterparts. Furthermore, Hestbeck (1995) analyzed data from 1961 – 1992 and concluded that production in prairie/parkland landscapes may have equaled production in northern regions. Additional evidence to support this was provided by stable isotope analysis, which indicated that production by prairie-breeding pintails on the prairies was lower than expected on the basis of the number of breeding adults the previous spring (Hebert and Wassenaar 2005).

Lifetime Reproductive Success

No information.

Life Span and Survivorship

Maximum longevity in the wild 21 yr 4 mo for a California-banded adult male recovered in Idaho (Klimkiewicz and Futcher 1989).

Northern Pintails have greater annual survival rates relative to other waterfowl (Miller and Duncan 1999). Based on recoveries from Northern Pintails banded during late summer-early fall from 1970-2003, annual survival was lower in the eastern region (i.e., Atlantic Flyway) compared to central (Mississippi and Central Flyways) and western (Pacific Flyway) regions (Rice et al. 2008, 2010). Average annual survival rates ranged from 60-67% for adult females, 49-56% for immature females, 74-76% for adult males, and 57-70% for immature males (Rice et al. 2010).

Regional survival models based on banding data from 1970-2003 differ among eastern (age, sex, and time groups based on harvest bag limits), central (age, sex, and time groups based on season length), and western (age, sex, and time groups based on environmental conditions in prairie Canada) regions (Rice et al. 2008). In the western region, annual survival during average and above-average environmental conditions was 64% for adult females, 59% for immature females, 74% for adult males, and 62% for immature males; during below average environmental conditions in prairie Canada survival increases, due to reduced nesting effort and overflight to more northern habitats, to 66% for adult females, 70% for immature females, 76% for adult males, and 71% for immature males (Rice et al. 2008). In the central region, annual survival estimates during liberal, moderate, and restrictive season lengths were 61%, 62%, and 70% for adult females; 64%, 70%, and 59% for immature females; 74%, 74%, and 81% for adult males; and 77%, 73%, and 73% for immature males (Rice et al. 2008). In the eastern region, annual survival estimates during liberal, moderate, and restrictive bag limits were 60%, 61%, and 55% for adult females; 41%, 51%, and 37% for immature females; 64%, 70%, and 70% for adult males; and 47%, 41%, and 58% for immature males (Rice et al. 2008). During spring in the Rainwater Basins of Nebraska no mortalities were recorded (Pearse et al. 2011). Cumulative February to mid-May survival was about 86% in the Central Valley of California and 93% in s. Oregon-ne. California (JPF unpubl. data).

Annual survival rates of Northern Pintails banded during late summer-early fall in sw. Alberta (1974-1990) and sw. Saskatchewan (1970-1984) were 73-76% for adult males, 62-65% for adult females, 66-81% for immature males, and 64-69% for immature females (U.S. Fish and Wildl. Serv. unpubl. data). Annual survival rates of individuals banded in the boreal forest were 40-44% during 1959-1960 (Lake et al. 2006). From 1989-2000, annual survival varied annually in the boreal forest for adult females (42-86%), hatch-year females (12-61%), adult males (42-80%), and hatch-year males (47-78%) (Lake et al. 2006). Northern Pintails banded on the Yukon-Kuskokwin Delta, Alaska, from 1990-2001 had an estimated annual survival rate of 78% for males and 60% for females (Nicolai et al. 2005). Annual survival rates of Northern Pintails banded during winter in major wintering regions in North America were higher for males (63-81%) than females (42-77%) (1950-1988; Hestbeck 1993b). Survival rates of birds banded late summer-early fall in various areas of California (1948-1979) were 64-76% for adult males, 49-66% for adult females, 49-60% for immature males, and 36-53% for immature females; survival rates for winter-banded birds were 66-77% for adult males and 51-65% for adult females (Rienecker 1987b). Survival rates during the fall-winter period (generally Sep-Mar), as determined with radio-tagged birds, varied by region; Sacramento Valley, CA–adult female 89% (Miller et al. 1995); San Joaquin Valley, CA (Sept-Mar)–adult female 68-82%, hatch-year female 57-73% (Fleskes et al. 2002); Louisiana (Oct-Feb)–adult female 75-85%, hatch-year female 59-67% (Cox et al. 1998); Playa Lakes Region, northwest TX (Oct-Feb)–adult and hatch-year females 69-93% (Moon and Haukos 2006); Middle Rio Grande Valley, NM (Nov-Feb)–adult male 57%, adult female 64% (Lee et al. 2007); Texas Gulf Coast (Oct-Feb)–adult female 31-60%, hatch-year female 17-48% (Anderson and Ballard 2006); Sinaloa, Mexico (Nov-Feb)–adult female 86-100%, hatch-year female 89-100% (Migoya and Baldassarre 1995). From 1987-1994 to 1998-2000, nonbreeding (Aug-Mar) Northern Pintail survival increased in the Sacramento Valley, CA (88 to 93%), Suisun Marsh, CA (77 to 87%), and San Joaquin Valley, CA (77 to 87%) (Fleskes et al. 2007).

Annual survival rates of adult males banded as flightless molters in s.-central Saskatchewan averaged 73% (60-85%; Anderson and Sterling 1974). Survival rate of radio-tagged adult females during the flightless period (Sep-Oct) in Sacramento Valley and Klamath Basin, CA, was 79% (Miller et al. 1992). Female survival in southern Saskatchewan from 30 Apr-14 Jul was 81% (Richkus et al. 2005).

Disease and Body Parasites

Diseases

Avian botulism (Clostridium botulinum) and avian cholera (Pasteurella multocida) are the most prevalent, chronic, and biologically significant bacterial diseases. Of all Northern Pintail carcasses recovered throughout U.S. and necropsied by National Wildlife Health Center (Natl. Biol. Serv. unpubl. records 1984–1994, n = 686), where cause of death was determined, 46% were killed by botulism, 22% by cholera. Large-scale die-offs from cholera are common in the Central Valley of California, Klamath Basin of ne. California and s. Oregon, Texas Playa Lakes region, and Nebraska's Rainwater Basin; very rare on the Atlantic Coast (Friend 1987a).

Pintails constituted 25% of waterfowl killed by cholera in the Rainwater Basin in spring 1980 (>8,000 birds; Brand 1984) and nearly 41% of all waterfowl carcasses retrieved from Texas Playa Lakes in 1977–1979, virtually all killed by cholera and botulism (Moore and Simpson 1981). Botulism is most prevalent in w. U.S. Tens of thousands of Northern Pintails died in the most serious botulism epizootics in California during 1940s–1960s (Rosen and Bischoff 1953, Parrish and Hunter 1969), but proper management has markedly reduced losses since. Botulism is also chronic in Utah's Great Salt Lake marshes and Great Plains, including the Canadian prairies (Bollinger et al. 2011). Duck virus enteritis, or duck plague, is the most important viral disease; Northern Pintail is less susceptible than other waterfowl (Friend 1987a). Northern Pintail has been a focal species for transmission studies involving avian influenza, including movement of highly pathogenic strains throughout Asia (Runstadler et al. 2007, Koehler et al. 2008, Jahangir et al. 2010).

Body Parasites

Sarcosporidiosis (Sarcocystis rileyi) was reported in the breast tissue of 5 of 436 Northern Pintails shot in the Sacramento Valley (MRM, 1979–1982 data) and in nearly 45% of Northern Pintails in Louisiana; adults showed greatest infestation rate (Chabreck 1965). Intestinal coccidia (Tyzzeria spp.) was recorded in 7% of autumn-collected Northern Pintails in Texas (Bristol et al. 1981), and renal coccidia (Eimeria spp.) found in 35% of the individuals sampled in Saskatchewan (Gajadhar et al. 1983).

The blood parasite Leucocytozoon simondi is lethal to ducklings but rarely to adults. In nw. Wisconsin, Trainer et al. (Trainer et al. 1962) documented this parasite in Northern Pintails and other waterfowl (in 17% of adults and 75% of juveniles, all waterfowl combined), and Bennett et al. (Bennett et al. 1982b) found 24% (n = 120) of Northern Pintails tested in Alberta and Saskatchewan to be infected with L. simondi or other hematozoans. In general, the effect of blood protozoans on populations of Northern Pintails is not known.

Leech (Theromyzon spp.) infestations, primarily of nasal chambers, have been reported in Northern Pintails from Manitoba, Northwest Territories, Utah, and N. Dakota (Trauger and Bartonek 1977); probably throughout the range of the species. Leeches are probably rarely fatal to adults but may kill ducklings.

Causes of Mortality

Exposure

Prairie nests are vulnerable to late spring snowfalls which may cause nesting pairs to abandon nests and territories (Krapu 1977). Northern Pintail ducklings at the Yukon-Kuskokwim Delta, AK, have died in large numbers from a combination of high tides and stormy weather (Grand and Flint1996a); many nests can be lost to storm flooding in coastal Alaska. Incidents of mortality are known from severe thunder-/hailstorms (Roth 1976, Calif. Dep. Fish and Game files); most died from hail impacts or grounding due to ice-coating and lightening strikes.

Predation

See Behavior: predation. In California, predation on females during nonbreeding season is concentrated in early fall (Miller et al. 1995) or in flightless period after nesting (Miller et al. 1992).

Competition With Other Species

No information.

Range

Initial Dispersal From Natal Site

No information on dispersal of hatch-year birds immediately after fledging and before the hunting season. Concerning return in the first year of life, fidelity to tyhe natal area is higher for juvenile females (13.0%, n = 115) than that for males (1.5%, n = 132) (Sowls 1955).

Fidelity To Breeding Site, Molting Areas, And Winter Home Range

Breeding Site. Probably varies with wetland availability and stability. In s. Manitoba, Sowls (Sowls 1955) found 39% of adult females returned to previous breeding area; he estimated actual return rate (considering survival overwinter) to be near 100%. Fidelity of adult males in all areas assumed to be very low because they follow mate to her nesting area. No information for prairie grassland areas; females may return but not remain when habitat conditions are poor (Derrickson 1977).

Molting Areas. Some wetlands are used traditionally during wing molt. Recaptures of banded flightless adult males in s. Saskatchewan suggest moderate return rates (Bellrose 1980). High fidelity rate estimates to banding sites have been reported for female (89.8% to 94.3%) and even male (77.4% to 87.2%) pintails from Alaska (Nicolai et al. 2005).

Winter Home Range. Northern Pintails demonstrate strong attachment to many winter sites, especially California, Gulf Coast, and Atlantic Coast (Hestbeck 1993a). Females show greater fidelity than males to California wintering areas (46 vs. 39%; Rienecker 1987a). In contrast, homing rate to Texas (<0.1%) is lower than rates for Mallard and Cinnamon Teal (Anas cyanoptera) (Fedynich et al. 1989).

Dispersal From Breeding Site

Adult males and nonbreeding or unsuccessful females migrate to traditional molting areas (Bellrose 1980). It is unclear where brood hens molt; probably near the breeding area. When flight feathers regrow, fall migration ensues. Adult males and unsuccessful females migrate first, young and successfully-breeding females later.

Home Range

Breeding home range is largest among Anas species, reflecting Northern Pintail's social behavior and preference for more seasonal wetlands. Home ranges for unpaired males, paired males, and paired females in N. Dakota were 579 ha, 896 ha, and 480 ha, respectively (Derrickson 1978). Mobility of females is greatest during prelaying but reduced throughout the nesting period.

In winter, this duck roosts on large sanctuaries by day and flies to dispersed feeding areas at night. Feeding and roosting areas form a functional home range that varies in size and location as winter progresses and food supply and availability change. In the Sacramento Valley, functional home ranges of radio-marked females shift from initial use areas on the west side of the valley (mostly national wildlife refuges and duck clubs) to the east side in late winter (mostly private agricultural lands) (MRM). Northern Pintails radio-marked in the San Joaquin Valley and Suisun Marsh shift to the Sacramento Valley in late winter (MRM); birds radio-marked in Louisiana move north to Arkansas during winter (Cox and Afton 2000).

Population Status

Numbers And Trends

One of the most abundant waterfowl species in North America; subject to population declines and recoveries. Continental breeding waterfowl surveys in May (Figure 5) showed high populations in the 1950s and 1970s (5.5–9.9 million) and record low numbers during extensive prairie drought in 1988–1991 (1.8–2.3 million) (U. S. Fish and Wildlife Service and Canadian Wildlife Service 1994). Numbers of breeding birds declined 11%/yr from 1975 to 1992 in Canadian prairies, 7%/yr in the U.S. prairies, and 3%/yr in n. Canada, but remained stable in Alaska (Figure 5) (U. S. Fish and Wildlife Service and Canadian Wildlife Service 1994). During high continental populations, 20–25% of the breeding Northern Pintails are recorded in Alaska; during severe prairie drought and low continental populations in 1988–1991, 42–58% were found in Alaska. Populations increased during the widespread prairie flood cycle of the mid-late 2000s, but responded less strongly than did other prairie-nesting duck species. In 2013, population estimate (3.3 million) in the traditional survey areas was ~15% below long-term average and remained below the conservation goal.

Rough annual winter population estimates (1955–1993): 660,000–4 million in Pacific Flyway; 268,000–1.8 million in Central Flyway; 250,000–1.4 million in Mississippi Flyway; 34,000–450,000 in Atlantic Flyway; and 204,000–1.2 million in Mexico (U.S. Fish and Wildl. Serv. unpubl. data; estimates vary widely because weather often limits survey coverage). In the 1970s and early 1980s, a period of large continental populations, 65% (55–78%) of the continental wintering population was recorded in the Pacific Flyway; in contrast, only 48% (35–67%) wintered in the Pacific Flyway in the late 1980s to early 1990s, a period of prairie drought and low continental populations (MRM, from U.S. Fish and Wildl. Serv. unpubl. data). During this period the proportion of continental wintering population in the combined Mississippi and Central flyways increased from 34% (29–43%) to 50% (31–64%). Numbers wintering in the Atlantic Flyway steadily declined from >400,000 in 1955–1956 (10.3% of total) to <70,000 (2.5% of total) in 1990.

Population Regulation

The continental population is influenced largely by variations in recruitment rates; annual and winter survival rates are relatively high (Rienecker 1987a, Raveling and Heitmeyer 1989, U. S. Fish and Wildlife Service and Canadian Wildlife Service 1992, Hestbeck 1993b, Rice et al. 2010), and harvest rates are low (<3%; U. S. Fish and Wildlife Service and Canadian Wildlife Service 1992). High populations are associated with abundant shallow wetlands in the Prairie Pothole Region during wet periods, low populations with prairie drought (Bellrose 1980).

There is evidence of weak density dependence in breeding population dynamics (Murray et al. 2010), a process that may vary spatially or with environmental conditions (Saether et al. 2008). Estimated age ratios (young to adult) during fall migration are positively correlated (r = 0.68, P < 0.01), with a proportion of population found in the Prairie Pothole Region (Ducks Unlimited 1990). Consequently, sustaining a large continental population seems particularly dependent on prairie production (Mattsson et al. 2012), although Alaska, n. Canada, and the inter-mountain w. U.S. also support the population base. Fall age ratio also tends to be lower following high counts of continental breeding population, consistent with density dependent production (Runge and Boomer 2005).

Continued wetland drainage and cultivation of preferred upland nest sites in grassland (Krapu 1977), intense predation on nesting hens (Sargeant et al. 1984), agricultural operations that destroy nests in stubble fields (Krapu 1977, Klett et al. 1988, Greenwood et al. 1995a), and other agricultural impacts on wetlands and upland nest sites (Turner et al. 1987) result in poor nest success (Greenwood et al. 1995a) and recruitment in prairies. See also Habitat: breeding range; Breeding: nest site; and above, Measures of Breeding Activity.

Recommended Citation

Clark, Robert G., Joseph P. Fleskes, Karla L. Guyn, David A. Haukos, Jane E. Austin and Michael R. Miller. 2014. Northern Pintail (Anas acuta), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA. https://doi.org/10.2173/bna.163