Le Conte's Sparrow Research Articles

Estimates of breeding season location for 4 mesic prairie bird species wintering along the Gulf Coast

During the last 2 centuries, widespread declines have been observed in migratory species, and these declines have largely been linked to anthropogenic causes. Migrants move across multiple spatiotemporal scales with wide-ranging movements that can cross multiple jurisdictions. Consequently, conservation and management require the incorporation of these wide-ranging movements. However, for many nongame species, basic information on migration and wintering ecology is poorly known. Yellow Rails (Coturnicops noveboracensis), LeConte's Sparrows (Ammospiza leconteii), Nelson's Sparrows (A. nelsoni), and Sedge Wrens (Cistothorus stellaris) represent a diverse avian assemblage that breeds in prairie potholes, boreal forest, and coastal areas of northern and eastern Canada and winters in coastal prairies in the southern United States. We used a stable deuterium isotope (δ2Hf) analysis to assign breeding season locations for individuals captured wintering in the southeastern US. We obtained deuterium values from secondary feathers of birds spending the nonbreeding season from Oklahoma and Texas east to Florida. We found substantial differences in the δ2Hf values of Yellow Rails and Nelson's Sparrows, with birds wintering in Oklahoma and the western Gulf of Mexico having δ2Hf values that were probabilistically assigned to the western half of their breeding range, while birds wintering in Florida were probabilistically assigned to the eastern portion of their breeding range. LeConte's Sparrow breeding season assignments for birds wintering in Texas and Oklahoma overlapped. Sedge Wrens did not exhibit spatial variation in isotope values.

Breeding Bird Occurrence Across a Gradient of Graminoid- to Shrub-Dominated Fens and Fire Histories

Population declines of birds affiliated with grasslands and grass-shrub habitats have been identified as a critical conservation concern. The effects of woody encroachment into grassland-dominated systems, which may contribute to species declines, has been examined mainly in upland systems. We examined occurrence of bird species across a gradient of graminoid- to shrub-dominated wetlands in the Upper Peninsula of Michigan and describe the habitat characteristics associated with their probability of occurrence at segment (100 × 100 m) and landscape (200 m buffer) scales. Because fire can suppress woody encroachment, we also examined the role of fire history, extending from 50 y on birds and habitat characteristics. We focused on seven species closely affiliated with grassland and grass-shrub habitats, but also found in wetlands: Sedge Wren (Asio flammeus), LeConte's Sparrow (Ammodramus leconteii), Savannah Sparrow (Passerculus sandwichensis), Bobolink (Dolichonyx oryzivorus), Common Yellowthroat (Geothlypis trichas), Swamp Sparrow (Melospiza georgiana), and Alder Flycatcher (Empidonax alnorum). We used nonparametric, multiplicative regression models to relate habitat variables and fire history to probability of species occurrence. Unlike studies in upland grasslands, none of the top models included measures of litter or graminoid height, and the highest probability of occurrence often was where graminoid cover was at intermediate rather than highest levels. Measures of woody cover or structure were important to all seven species modeled. We observed few clear differences in habitat metrics across fire history categories beyond the first year of burning. Years since last burned was in the best model for four of the seven species, despite high variability of habitat metrics within fire history categories; those species were more likely to occur in segments burned 15–19 y earlier. Infrequent light- to moderate-severity fires in fens had little effect on focal species occurrence beyond the first year after burning and little long-term effect to suppress woody cover.

Noteworthy Wintering Records and Habitat of LeConte's Sparrow (Ammospiza leconteii) in Grasslands of Coahuila, Northern Mexico

There is limited knowledge on the winter distribution of LeConte's Sparrow, especially in northern Mexico where it is considered scarce and rare. We captured and banded two individuals of LeConte's Sparrow (Ammospiza leconteii) during consecutive winters (2016-2017, 2017-2018; one in each season) in an intermountain grassland of northern Coahuila, Mexico. These records were ca. 300 km outside the known wintering range of this species. Vegetation was variable at both sites. The first wintering site consisted of low grass cover (18.7%) dominated by Eragrostis and Bouteloua; the second site consisted of 72.6% grass cover, mainly composed of Bouteloua and Botriochloa.

Noteworthy Wintering Records and Habitat of LeConte's Sparrow (Ammospiza leconteii) in Grasslands of Coahuila, Northern Mexico

Noteworthy Wintering Records and Habitat of LeConte's Sparrow (Ammospiza leconteii) in Grasslands of Coahuila, Northern Mexico

Evaluation of autonomous recording units for detecting 3 species of secretive marsh birds

ABSTRACTPopulation status and habitat use of yellow rails (Coturnicops noveboracensis), Nelson's sparrows (Ammodramus nelsoni), and Le Conte's sparrows (A. leconteii) are poorly known, so standardized surveys of these species are needed to inform conservation planning and management. A protocol for monitoring secretive marsh birds exists; however, these species regularly call at night and may be missed during early morning surveys. We tested the effectiveness of autonomous recording units (hereafter, recording units) to survey these species by analyzing recorded vocalizations using bioacoustics software. We deployed 22 recording units at 54 sites in northern Minnesota and eastern North Dakota, USA, and conducted traditional broadcast surveys during May–June, 2010 and 2011. We compared detection probabilities between recording units and standard monitoring protocols using robust‐design occupancy models. On average, recording units detected 0.59 (SE = 0.11) fewer Le Conte's sparrows, 0.76 (SE = 0.15) fewer Nelson's sparrows, and 1.01 (SE = 0.14) fewer yellow rails per survey than were detected using the standard protocol. Detection probabilities using the standard protocol averaged 0.95 (yellow rail; 95% CI = 0.86–0.98), 0.93 (Le Conte's sparrow; 95% CI = 0.78–0.98), and 0.89 (Nelson's sparrow; 95% CI = 0.56–0.98), but averaged 0.71 (yellow rail; 95% CI = 0.56–0.83), 0.61 (Le Conte's sparrow; 95% CI = 0.42–0.78), and 0.51 (Nelson's sparrow; 95% CI = 0.19–0.82) using recording units. Reduced detection by recording units was likely due to the ability of human listeners to identify birds calling at greater distances. Recording units may be effective for surveying nocturnal secretive marsh birds if investigators correct for differential detectability. Reduced detectability may be outweighed by the increased spatial and temporal coverage feasible with recording units. © 2015 The Wildlife Society.

Structural heterogeneity increases diversity of non‐breeding grassland birds

Grassland birds have experienced greater population declines than any other guild of birds in North America, and yet we know little about habitat use and the affects of management during their non‐breeding period on wintering grounds. The paucity of information on wintering grassland birds limits our ability to develop effective conservation strategies. We investigated habitat use by the winter bird community in grasslands with restored heterogeneity resulting from the interactive effects of fire and grazing. We used 500 m line transects distributed across patches (i.e., <13, 13–24, and >24 months post disturbance) resulting from spring burning with growing season grazing (April‐Sept) and quantified avian relative abundance, community structure, and probability of patch occupancy while accounting for imperfect detection. Grassland structure that resulted from the fire‐grazing interaction created heterogeneity among patches that influenced avian habitat use during winter. Generalist birds such as the Savannah Sparrow (Passerculus sandwichensis) and meadowlarks (Sturnellaspp.) were relatively common in all patch types while more specialized species such as the Smith's Longspur (Calcarius pictus) and Le Conte's Sparrow (Ammodramus leconteii) reached greatest abundance and probability of occupancy in the patches with the least and greatest time post disturbance, respectively. This research provides novel information on the response of wintering birds to restored ecological processes in grasslands and can improve efforts to create effective conservation strategies. Our findings add to a growing body of literature supporting the use of fire and grazing to create a shifting grassland mosaic that increases vegetation structural and compositional heterogeneity and maximizes native biodiversity within rangeland ecosystems through the conservation of natural patterns and processes.

Winter Bird Habitat Use in a Heterogeneous Tallgrass Prairie

In the Flint Hills of Kansas and Oklahoma, U.S.A., grazing land is managed predominantly to promote homogeneous grassland structure. This potentially limits the diversity of habitats for grassland obligate songbirds with narrow habitat preferences during the breeding season, prompting ecologists and conservationists to call for managing rangelands for increased heterogeneity. The Flint Hills also hosts multiple species of conservation concern during winter, but avian habitat requirements are less well known during this period and seldom considered in management recommendations. We investigated the influence of vegetation structure on occurrence of songbirds overwintering at The Nature Conservancy's Tallgrass Prairie Preserve in Osage County, Oklahoma, where fire and grazing are used to increase structural and compositional heterogeneity. During the winters of 2008–2009 and 2009–2010, we used an area-search method to survey 149, 1 ha plots distributed among patches that represented a wide gradient in vegetation structure and 1–3 growing seasons since fire. We modeled occurrence of Le Conte's Sparrow (Ammodramus leconteii), Sedge Wren (Cistothorus platensis), Savannah Sparrow (Passerculus sandwichensis), and Smith's Longspur (Calcarius pictus) with a combination of fine-scale vegetation (e.g., litter depth in sampling plots), landscape-scale factors (e.g., distance to utility poles), and time since fire. Vegetation height was the most consistent predictor for three species, with Le Conte's Sparrow and Sedge Wren associated with tall structure and Smith's Longspur associated with shorter structure. Occurrence of Smith's Longspur was too low to adequately model effects of burn age, but fine-scale vegetation structure used by Le Conte's Sparrow and Sedge Wren was available in plots irrespective of time since fire. A variety of management techniques for creating habitat heterogeneity have the potential to promote grassland songbird diversity during winter, but further study is needed.

Songbird abundance in native and planted grassland varies with type and amount of grassland in the surrounding landscape

Agriculture and wildlife conservation programs have converted vast amounts of cropland into grasslands planted with exotic species. Understanding how landscape context influences avian use of native and planted grasslands is essential for developing effective conservation strategies in agricultural landscapes. Our primary objective was to determine the extent to which the amount and type of grassland in the surrounding landscape influences the abundance of grassland songbird species on native and planted grassland parcels in southern Saskatchewan and Alberta, Canada. Bird abundance was more strongly influenced by the amount and type of grassland within 400 m of breeding parcels than at larger spatial scales. Grassland specialists responded similarly to habitat and landscape type over both years and provinces. Sprague's pipit (Anthus spragueii) and Baird's sparrow (Ammodramus bairdii) were most common in native grassland parcels surrounded by native grassland and were more likely to occur in planted grasslands surrounded by native grassland. Bobolinks (Dolichonyx oryzivorus) were most common in planted grassland parcels, but their abundance increased with the amount of native grassland surrounding these parcels. Our findings indicate that the suitability of planted grasslands for these species is influenced by their proximity to native grassland. Grassland generalists showed mixed responses to habitat and landscape type over the 2 years (Le Conte's sparrow (Ammodramus leconteii)) and between provinces (Savannah sparrow (Passerculus sand- wichensis) and western meadowlark (Sturnella neglecta)). Management to benefit grassland specialists should therefore consider the landscape context when seeding cultivated land to non-native grassland and conserve extant native grassland. 2013 The Wildlife Society.

Effects of Prescribed Fire on Vegetation and Passerine Birds in Northern Mixed‐Grass Prairie

ABSTRACTPrescribed fire is used widely to manage grasslands on National Wildlife Refuges and other public lands in the northern Great Plains, but its effects on habitat use or production of wildlife in the region are poorly understood. During 1998–2003, we used point counts to examine effects of prescribed fire on vegetation and passerines in a mixed‐grass prairie complex in north‐central North Dakota, USA (n= 7 units, each 40–70 ha). Vegetation structure and, to a lesser extent, plant community composition varied with year of study (likely related to changes in annual precipitation) and with number of growing seasons since fire. Fire altered plant structure, especially the amount of residual vegetation, which in turn influenced bird species richness and abundance. The number of indicated pairs for sedge wren (Cistothorus platensis), clay‐colored sparrow (Spizella pallida), Le Conte's sparrow (Ammodramus leconteii), Savannah sparrow (Passerculus sandwichensis), and bobolink (Dolichonyx oryzivorus) were lowest during the first postfire growing season but generally increased and stabilized within 2–3 postfire growing seasons. Our results support the premise that grassland passerines are well‐adapted to frequent, periodic fires, generally corresponding to those occurring prior to Euro‐American settlement of the region. Prescribed fire is important for reducing tree and shrub invasion, restoring biological integrity of plant communities, and maintaining or enhancing populations of grassland‐dependent bird species. Managers in the northern mixed‐grass prairie region should not be overly concerned about reductions in bird abundances that are limited mostly to the first growing season after fire.

Home-Range Size and Site Tenacity of Overwintering Le Conte's Sparrows in a Fire Managed Prairie

We evaluated home-range size and site tenacity of Le Conte's Sparrows (Ammodramus lecontii) during winter 2002–2003 at Brazoria National Wildlife Refuge, Texas. Twenty-six wintering Le Conte's Sparrows were radiomarked in 1- and 2-year post-burn units, and monitored for ∼10 days. Additionally, 1-ha plots on each 1-, 2- and 3-year (n = 15) post-burn units were flush-netted once monthly. Telemetry results indicated Le Conte's Sparrows were sedentary during winter with a 50% probability mean home-range of 2.41 ha (72% < 1 ha) and a 95% probability mean home range of 10.31 ha (44% < 1 ha and 55% < 1.5 ha). Home-range size did not differ between post-burn year 1 and 2 (P = 0.227). Le Conte's Sparrows appeared to exhibit a behavioral response to flush-netting (P < 0.001) with estimated capture probability of 0.462 and recapture probability of 0.056. Our findings suggest Le Conte's Sparrows remain fairly sedentary throughout the winter.

Winter Ecology of Yellow Rails Based on South Carolina Specimens

Arthur T. Wayne collected 58 Yellow Rails (Coturnicops noveboracensis) during seven winters between 1903 and 1918 at one locality on the Atlantic coast in Charleston County, South Carolina. The collection represents the largest known series of Yellow Rails from a single wintering site and provides information about the winter ecology of this species. There was no evidence that Yellow Rail numbers varied between winters. The sex ratio was significantly biased toward females suggesting the occurrence of differential wintering. Yellow Rails were collected mainly in wet (freshwater) fields with short dense grass, the same features of Yellow Rail habitats in coastal Texas. Yellow Rails were consistently located in the same habitats as LeConte's Sparrow (Ammodramus leconteii). Two other grassland species, Henslow's Sparrows (A. henslowii) and Sedge Wrens (Cistothorus palustris), had habitat occupancy patterns significantly different from that of Yellow Rails.

Interspecific Interactions between Marsh-dwelling Ammodramus Sparrows at a Migration Stopover

Abstract The social behaviors of Le Conte's (Ammodramus leconteii) and Nelson's Sharp-tailed (A. nelsoni) sparrows are poorly documented, as are their interactions with one another, even in the prairie marshes they share during the breeding season. We report the regular coincident presence and similar habitat associations of these species at a fall migration stopover, the Baker University Wetlands, near Lawrence, Kansas, over an 11-year period, and describe social behaviors (several previously unrecorded) at the site, including an aggressive interspecific encounter.

HABITAT RELATIONSHIPS OF BIRDS OVERWINTERING IN A MANAGED COASTAL PRAIRIE

Abstract Grassland birds are considered to be rapidly declining in North America. Management approaches for grassland birds frequently rely on prescribed burning to maintain habitat in suitable condition. We evaluated the relationships among years since burn, vegetation structure, and overwintering grassland bird abundance in coastal prairie. Le Conte's Sparrows (Ammodramus leconteii) were most common in areas that had: (1) been burned within the previous 2 years, (2) medium density herbaceous vegetation, and (3) sparse shrub densities. Savannah Sparrows (Passerculus sandwichensis) were associated with areas: (1) burned within 1 year, (2) with sparse herbaceous vegetation, and (3) with sparse shrub densities. Sedge Wrens (Cistothorus platensis) were most common in areas that had: (1) burned greater than 2 years prior and (2) dense herbaceous vegetation. Swamp Sparrows (Melospiza georgiana): (1) were most common in areas of dense shrubs, (2) not related to time since burnings, and (3) demonstrated no relat...

Comparison of survey methods for wintering grassland birds

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New Nesting Records of the Le Conte's Sparrow, &lt;em&gt;Ammospiza leconteii&lt;/em&gt;, from Northeastern Ontario, with Some Notes on Nesting Behaviour

Le Conte’s Sparrow is sparsely distributed through northeastern Ontario with no confirmed records from Algoma District and eastern Lake Superior. Two nests were found in open poor fen between Wawa and Hawk Junction in central Algoma District in 1999. Notes on behaviour, nests, nestling development and feeding effort were taken during 9 hours and 38 minutes at one nest over three days.

Habitat and nesting of Le Conte's Sparrows in the northern tallgrass prairie

Little is known about the breeding biology of the Le Conte's Sparrow (Ammodramus leconteii), probably because of its secretive nature. We provide new information on several aspects of Le Conte's Sparrow breeding biology, including rates of nest parasitism by Brown-headed Cowbirds (Molothrus ater) and potential factors affecting breeding densities and nesting success of the species. Our study was conducted in the tallgrass prairie of northwestern Minnesota and southeastern North Dakota during 1998–2002. Breeding densities varied among years, but this variation was not clearly linked to climatic patterns. Vegetation had some influence on densities of Le Conte's Sparrows; densities were highest in grasslands with moderate amounts of bare ground. Prairie patch size and the percentage of shrubs and trees in the landscape had no recognizable influence on density. Nesting success was highly variable among sites and years and increased slightly with distance from trees. Rates of nest parasitism were low (1 of 50 nests parasitized), and clutch sizes were similar to those of other studies of Le Conte's Sparrows.

Area Requirements of Grassland Birds: A Regional Perspective

Area requirements of grassland birds have not been studied except in tallgrass prairie. We studied the relation between both species-occurrence and density and patch size by conducting 699 fixed-radius point counts of 15 bird species on 303 restored grassland areas in nine counties in four northern Great Plains states. Northern Harrier (Circus cyaneus), Sedge Wren (Cistothorus platensis), Clay-colored Sparrow (Spizella pallida), Grasshopper Sparrow (Ammodramus savannarum), Baird's Sparrow (Ammodramus bairdii), Le Conte's Sparrow (Ammodramus leconteii), and Bobolink (Dolichonyx oryzivorus) were shown to favor larger grassland patches in one or more counties. Evidence of area sensitivity was weak or ambivalent for Eastern Kingbird (Tyrannus tyrannus), Common Yellowthroat (Geothlypis trichas), Savannah Sparrow (Passerculus sandwichensis), and Western Meadowlark (Sturnella neglecta). Red-winged Blackbirds (Agelaius phoeniceus) preferred larger patches in some counties, and smaller patches in others. Mourning Doves (Zenaida macroura) and Brown- headed Cowbirds (Molothrus ater) tended to favor smaller grassland patches. Three species showed greater area sensitivity in counties where each species was more common. Five species demonstrated some spatial pattern of area sensitivity, either north to south or east to west. This study demonstrates the importance of replication in space; results from one area may not apply to others because of differences in study design, analytical methods, location relative to range of the species, and surrounding landscapes.

AREA REQUIREMENTS OF GRASSLAND BIRDS: A REGIONAL PERSPECTIVE

Abstract Area requirements of grassland birds have not been studied except in tallgrass prairie. We studied the relation between both species-occurrence and density and patch size by conducting 699 fixed-radius point counts of 15 bird species on 303 restored grassland areas in nine counties in four northern Great Plains states. Northern Harrier (Circus cyaneus), Sedge Wren (Cistothorus platensis), Clay-colored Sparrow (Spizella pallida), Grasshopper Sparrow (Ammodramus savannarum), Baird's Sparrow (Ammodramus bairdii), Le Conte's Sparrow (Ammodramus leconteii), and Bobolink (Dolichonyx oryzivorus) were shown to favor larger grassland patches in one or more counties. Evidence of area sensitivity was weak or ambivalent for Eastern Kingbird (Tyrannus tyrannus), Common Yellowthroat (Geothlypis trichas), Savannah Sparrow (Passerculus sandwichensis), and Western Meadowlark (Sturnella neglecta). Red-winged Blackbirds (Agelaius phoeniceus) preferred larger patches in some counties, and smaller patches in others. ...

Area Requirements of Grassland Birds: A Regional Perspective

AbstractArea requirements of grassland birds have not been studied except in tallgrass prairie. We studied the relation between both species-occurrence and density and patch size by conducting 699 fixed-radius point counts of 15 bird species on 303 restored grassland areas in nine counties in four northern Great Plains states. Northern Harrier (Circus cyaneus), Sedge Wren (Cistothorus platensis), Clay-colored Sparrow (Spizella pallida), Grasshopper Sparrow (Ammodramus savannarum), Baird's Sparrow (Ammodramus bairdii), Le Conte's Sparrow (Ammodramus leconteii), and Bobolink (Dolichonyx oryzivorus) were shown to favor larger grassland patches in one or more counties. Evidence of area sensitivity was weak or ambivalent for Eastern Kingbird (Tyrannus tyrannus), Common Yellowthroat (Geothlypis trichas), Savannah Sparrow (Passerculus sandwichensis), and Western Meadowlark (Sturnella neglecta). Red-winged Blackbirds (Agelaius phoeniceus) preferred larger patches in some counties, and smaller patches in others. Mourning Doves (Zenaida macroura) and Brown- headed Cowbirds (Molothrus ater) tended to favor smaller grassland patches. Three species showed greater area sensitivity in counties where each species was more common. Five species demonstrated some spatial pattern of area sensitivity, either north to south or east to west. This study demonstrates the importance of replication in space; results from one area may not apply to others because of differences in study design, analytical methods, location relative to range of the species, and surrounding landscapes.

Effects of Protective Fencing on Birds, Lizards, and Black-Tailed Hares in the Western Mojave Desert.

/ Effects of protective fencing on birds, lizards, black-tailed hares (Lepus californicus), perennial plant cover, and structural diversity of perennial plants were evaluated from spring 1994 through winter 1995 at the Desert Tortoise Research Natural Area (DTNA), in the Mojave Desert, California. Abundance and species richness of birds were higher inside than outside the DTNA, and effects were larger during breeding than wintering seasons and during a high than a low rainfall year. Ash-throated flycatchers (Myiarchus cinerascens), cactus wrens (Campylorhynchus brunneicapillus), LeConte's thrashers (Toxostoma lecontei), loggerhead shrikes (Lanius ludovicianus), sage sparrows (Amphispiza belli), and verdins (Auriparus flaviceps) were more abundant inside than outside the DTNA. Nesting activity was also more frequent inside. Total abundance and species richness of lizards and individual abundances of western whiptail lizards (Cnemidophorous tigris) and desert spiny lizards (Sceloporus magister) were higher inside than outside. In contrast, abundance of black-tailed hares was lower inside. Structural diversity of the perennial plant community did not differ due to protection, but cover was 50% higher in protected areas. Black-tailed hares generally prefer areas of low perennial plant cover, which may explain why they were more abundant outside than inside the DTNA. Habitat structure may not affect bird and lizard communities as much as availability of food at this desert site, and the greater abundance and species richness of vertebrates inside than outside the DTNA may correlate with abundances of seeds and invertebrate prey. KEY WORDS: Birds; Fenced protection; Lepus californicus, Lizards; Mojave Desert; Off-highway vehicles; Protected area management; Sheep grazing