scholarly journals Mixed-Grass Prairie Passerines Exhibit Weak and Variable Responses to Patch Size

The Auk ◽  
2006 ◽  
Vol 123 (3) ◽  
pp. 807-821 ◽  
Author(s):  
Stephen K. Davis ◽  
R. Mark Brigham ◽  
Terry L. Shaffer ◽  
Paul C. James
Keyword(s):  
Tallgrass Prairie ◽  
Patch Size ◽  
Nest Survival ◽  
Bird Populations ◽  
Mixed Grass Prairie ◽  
Bird Density ◽  
Anthus Spragueii ◽  
Mixed Grass ◽  
Sprague's Pipit ◽  
Time Specific

Abstract Much of our current understanding of the demographic effects of habitat fragmentation on bird populations is derived from studies of passerines in forests and tallgrass prairie surrounded by woody vegetation. We quantified grassland bird density, nest survival, and productivity in 41 native mixed-grass prairie pastures during 1997-2000 in southern Saskatchewan, Canada. Pastures ranged in size from 18 ha to 11,600 ha and were typically surrounded by agriculture (i.e., ranching and annual cropping). Grassland passerines did not respond strongly or uniformly to patch size. Sprague's Pipit (Anthus spragueii) was the only species whose density increased with pasture size. Patch size had minimal influence on nest survival of Sprague's Pipit or Clay-colored Sparrow (Spizella pallida); whereas nest survival increased with patch size for Savannah Sparrow (Passerculus sandwichensis) and declined for Baird's Sparrow (Ammodramus bairdii), Chestnut-collared Longspur (Calcarius ornatus), and Western Meadowlark (Sturnella neglecta). Time-specific factors (i.e., nest age, date, and year) were more important predictors of nest survival than patch size. Exploratory analyses indicated that effects of edge distance, pasture shape, or landscape on nest survival were just as likely as patch-size effects. However, effects of edge on Chestnut-collared Longspurs may be governed by landscape-level factors, because nest survival decreased with distance to edge in landscapes with increased amounts of cropland. Our results indicate that mixed-grass prairie parcels ≥18 ha play a role in the conservation of several grassland passerine species currently in decline, but the conservation of Sprague's Pipit likely depends on maintaining larger tracts of native prairie. Les Passereaux des Prairies Herbacées Montrent des Réponses Faibles et Variables en Réponse à la Taille des Parcelles d'Habitats

scholarly journals Area Sensitivity in Grassland Passerines: Effects of Patch Size, Patch Shape, and Vegetation Structure on Bird Abundance and Occurrence in Southern Saskatchewan

The Auk ◽  
2004 ◽  
Vol 121 (4) ◽  
pp. 1130-1145 ◽  
Author(s):  
Stephen K. Davis
Keyword(s):  
Habitat Fragmentation ◽  
Tallgrass Prairie ◽  
Vegetation Structure ◽  
Native Species ◽  
Patch Size ◽  
Grassland Birds ◽  
Bird Abundance ◽  
Mixed Grass Prairie ◽  
Mixed Grass ◽  
Area Sensitivity

Abstract Information on area sensitivity and effects of habitat fragmentation has come largely from forest and tallgrass-prairie habitats. Research from other ecosystems is required to determine whether the fragmentation paradigm derived from those studies is applicable to passerine communities elsewhere. I examined the effects of habitat fragmentation on abundance and occurrence of nine species of mixed-grass prairie passerines in southern Saskatchewan. I conducted 190 point-counts in 1996 and 1997 on 89 pastures ranging in size from 8 to 6,475 ha. Sprague's Pipit (Anthus spragueii), Baird's Sparrow (Ammodramus bairdii), Grasshopper Sparrow (A. savannarum), and Chestnut-collared Longspur (Calcarius ornatus) were found to be area-sensitive, in that they were more abundant or occurred more frequently, or both, in larger patches of mixed-grass prairie. However, the ratio of edge to interior habitat was a better predictor of area sensitivity than patch size in most cases. Horned Lark (Eremophila alpestris), Savannah Sparrow (Passerculus sandwichensis), Clay-colored Sparrow (Spizella pallida), Western Meadowlark (Sturnella neglecta), and Brown-headed Cowbird (Molothrus ater) were insensitive to patch size, though occurrence of Clay-colored Sparrow and Western Meadowlark tended to be greater in smaller pastures. Vegetation structure was also found to be an important predictor of grassland songbird abundance and occurrence, in that it explained additional variation not accounted for by patch size or the ratio of edge to interior habitat. Although protection of large contiguous tracts of habitat is essential to conservation of native species, small native-prairie patches with minimal edge habitat also play a vital role in conservation of grassland birds.

scholarly journals Nest-Site Selection Patterns and the Influence of Vegetation on Nest Survival of Mixed-Grass Prairie Passerines

The Condor ◽  
2005 ◽  
Vol 107 (3) ◽  
pp. 605-616 ◽  
Author(s):  
Stephen K. Davis
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Nest Survival ◽  
Nest Site Selection ◽  
Spatial And Temporal Variation ◽  
Passerculus Sandwichensis ◽  
Bird Populations ◽  
Anthus Spragueii ◽  
Para Determinar ◽  
Sturnella Neglecta

Abstract Identification of habitat features influencing reproduction and survival are essential for the management and long-term viability of grassland bird populations. I quantified vegetation structure at nests and random sites in southern Saskatchewan, Canada, to determine which microhabitat features are important in nest-site selection by Sprague's Pipit (Anthus spragueii), Savannah Sparrow (Passerculus sandwichensis), Baird's Sparrow (Ammodramus bairdii), Chestnut-collared Longspur (Calcarius ornatus), and Western Meadowlark (Sturnella neglecta). In addition, I related microhabitat features to nest survival to determine whether predation might influence their choice of nest sites. Grassland passerines exhibited nonrandom nest-placement patterns and built their nests in sites that were characterized by a greater density of dead vegetation within 30 cm of the ground, increased amounts of litter, and reduced coverage of bare ground. In addition, each species nested in taller vegetation than that found at random sites. However, nests were partitioned along a vegetation gradient ranging from relatively short and sparse (e.g., Chestnut-collared Longspur) to relatively tall and dense (e.g., Western Meadowlark). Nest survival varied with time-specific variables (nest age and date) and year, with nest-site vegetation explaining additional variation not accounted for by these effects. However, vegetation effects were highly variable compared to age effects. Diverse predator communities, spatial and temporal variation in selection pressures, and other constraints may account for inconsistent relationships between nest survival and nest-site characteristics for grassland passerines. Patrones de Selección de Sitios de Nidificación y la Influencia de la Vegetación en la Supervivencia de Nidos de Aves Paserinas de Praderas de Pastos Mixtos Resumen. La identificación de las características del ambiente que influencian la reproducción y la supervivencia son esenciales para el manejo y la viabilidad al largo plazo de las poblaciones de las aves de pastizal. Cuantifiqué la estructura de la vegetación alrededor de los nidos y en sitios aleatorios en el sur de Saskatchewan, Canadá, para determinar cuáles rasgos micro-ambientales son importantes en la selección de nidos por parte de Anthus spragueii, Passerculus sandwichensis, Ammodramus bairdii, Calcarius ornatus y Sturnella neglecta. Adicionalmente, relacioné los rasgos micro-ambientales con la supervivencia de los nidos para determinar si la depredación podría influir sobre la elección de los sitios de nidificación. Las aves paserinas de pastizal mostraron patrones no aleatorios de ubicación de los nidos y construyeron sus nidos en sitios que se caracterizaron por una densidad más alta de vegetación muerta en los primeros 30 cm desde el suelo, una mayor cantidad de hojarasca y una baja cobertura de suelo desnudo. Adicionalmente, cada especie nidificó en sitios con vegetación más alta que la de los sitios elegidos al azar. Sin embargo, los nidos se distribuyeron a lo largo de un gradiente de vegetación desde relativamente corta y esparcida (e.g., Calcarius ornatus) a relativamente alta y densa (e.g., Sturnella neglecta). La supervivencia de los nidos varió en relación con variables que dependen del tiempo (edad del nido y fecha) y del año, mientras que la vegetación de los sitios donde se ubicaron los nidos explicó una parte adicional de la variación no explicada por estos factores. Sin embargo, los efectos de la vegetación fueron muy variables comparados de modo general con los efectos de la edad. Las diferencias en las comunidades de depredadores, la variación espacial y temporal en las presiones de selección y otras limitantes podrían explicar las relaciones inconsistentes entre la supervivencia de los nidos y las características de los sitios de nidificación para las aves paserinas de pastizal.

Factors Affecting Songbird Nest Survival in Northern Mixed-Grass Prairie

2010 ◽  
Vol 74 (2) ◽  
pp. 257-264 ◽  
Author(s):  
Courtney K. Kerns ◽  
Mark R. Ryan ◽  
Robert K. Murphy ◽  
Frank R. Thompson ◽  
Cory S. Rubin
Keyword(s):  
Nest Survival ◽  
Factors Affecting ◽  
Mixed Grass Prairie ◽  
Mixed Grass

Little Brown Birds

2020 ◽  
pp. 133-143
Author(s):  
Richard Bohannon
Keyword(s):  
North Dakota ◽  
Republican Party ◽  
Large Scale ◽  
State Legislature ◽  
Mixed Grass Prairie ◽  
Oil Development ◽  
History Of ◽  
Mixed Grass ◽  
Sprague's Pipit ◽  
Party State

This chapter narrates the author's trip to western North Dakota's Bakken region, where he was mapping out habitat fragmentation caused by the recent surge in oil development. The research was really just an excuse to go out birding for a few days. Two birds are confined to the northern mixed-grass prairie: the Baird's sparrow and the Sprague's pipit. Both are small, brown birds, not terribly charismatic — what birders call LBJs or “little brown jobs” — and both are declining in population. The chapter then discusses how oil development occurs with seeming abandon in the Bakken and is only lightly regulated. Despite a history of progressivism and socialism in the American prairies, North Dakota today is essentially a one-party state — an explicitly oil-friendly Republican Party has held the governorship and both houses of the state legislature for years. Unlike resistance in parts of the East Coast, there have been no large-scale protests in North Dakota, save resistance to the pipeline by the Standing Rock reservation.

MIXED-GRASS PRAIRIE PASSERINES EXHIBIT WEAK AND VARIABLE RESPONSES TO PATCH SIZE

The Auk ◽  
2006 ◽  
Vol 123 (3) ◽  
pp. 807 ◽  
Author(s):  
Stephen K. Davis ◽  
R. Mark Brigham ◽  
Terry L. Shaffer ◽  
Paul C. James
Keyword(s):  
Patch Size ◽  
Mixed Grass Prairie ◽  
Mixed Grass

Contrasting nest survival patterns for ducks and songbirds in northern mixed-grass prairie

2017 ◽  
Vol 81 (4) ◽  
pp. 641-651 ◽  
Author(s):  
Todd A. Grant ◽  
Terry L. Shaffer ◽  
Elizabeth M. Madden ◽  
Melvin P. Nenneman
Keyword(s):  
Nest Survival ◽  
Mixed Grass Prairie ◽  
Mixed Grass ◽  
Survival Patterns

scholarly journals Territory Size in Mixed-grass Prairie Songbirds

2011 ◽  
Vol 125 (1) ◽  
pp. 12 ◽  
Author(s):  
Stephanie L. Jones
Keyword(s):  
Significant Variation ◽  
Bird Species ◽  
Site Quality ◽  
Territory Size ◽  
North Central ◽  
Mixed Grass Prairie ◽  
Breeding Territory ◽  
Anthus Spragueii ◽  
Mixed Grass ◽  
Central Montana

I estimated breeding territory size in mixed-grass prairie songbirds, and explored how it varied among bird species, time-of-season, and year. The study was conducted at Bowdoin National Wildlife Refuge in north-central Montana during 2007-2009. Across all species, months and years, mean breeding territory size was estimated at 0.43 ha (SE = 0.03, n = 129). Estimates were nearly identical across study species: Sprague's Pipits (Anthus spragueii), Grasshopper (Ammodramus savannarum), and Baird's (A. bairdii) sparrows. There was no significant variation in territory size across months, suggesting little to no dependence on nest phase. In contrast, I found significant variation in territory size among years (P = 0.034), that did not interact meaningfully with species (R2 = 0.02, P = 0.603). This suggests that factors that vary annually appear to be affecting all bird species in a similar manner, which could be related to differences in vegetation structure and/or site quality (perhaps as a function of weather) or less likely, variation in population density.

scholarly journals Nesting Behaviour and Reproductive Success of Sprague’s Pipit (Anthus spragueii) and Vesper Sparrow (Pooecetes gramineus) during Pipeline Construction

2016 ◽  
Vol 130 (2) ◽  
pp. 99
Author(s):  
Glenn C Sutter ◽  
Stephen K Davis ◽  
Janice C Skiffington ◽  
Laura M Keating ◽  
Lois A Pittaway
Keyword(s):  
Reproductive Success ◽  
Nest Survival ◽  
Breeding Habitat ◽  
Activity Period ◽  
Noise Levels ◽  
Pipeline Construction ◽  
Oil Pipeline ◽  
Anthus Spragueii ◽  
Daily Nest Survival ◽  
Sprague's Pipit

Industrial activity occurs in the breeding habitat of several species at risk, including the federally threatened Sprague’s Pipit (Anthus spragueii). To evaluate whether oil pipeline construction reduces the productivity of this species, we examined (a) noise levels in relation to distance from the pipeline right-of-way (ROW), (b) the extent to which noise and song frequencies overlapped, (c) the distribution of Sprague’s Pipit nests relative to the ROW, and (d) Sprague’s Pipit reproductive success during exposure to pipeline construction and clean-up activity. We also examined the songs, nest locations, and reproductive success of the Vesper Sparrow (Pooecetes gramineus) for comparison. Study plots (400 × 400 m, n = 30) were established in grassland adjacent to the pipeline ROW or 600 m away from the ROW in similar habitat. Mean maximum noise levels during pipeline activity included frequencies that overlapped the song range of both species and were louder than the recommended 49 dB threshold up to 250 m from the ROW. Sprague’s Pipit nests were evenly distributed across close and distant plots, whereas Vesper Sparrow nests were more abundant within 50 m of the ROW. Sprague’s Pipit daily nest survival rate and the number of young surviving to day 8 both increased with increasing distance from the ROW; and Vesper Sparrow daily nest survival decreased slightly with exposure to pipeline activities. Our findings validate the restricted activity period and indicate that the recommended setback distance of 350 m is a reasonable guideline for pipeline projects.

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