ANNUAL SURVIVORSHIP OF THE SEDENTARY RUFOUS-CROWNED SPARROW (AIMOPHILA RUFICEPS): NO DETECTABLE EFFECTS OF EDGE OR RAINFALL IN SOUTHERN CALIFORNIA (original) (raw)
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The Auk, 2001
We investigated site fidelity and apparent survival in a promiscuous population of Saltmarsh Sharp-tailed Sparrows (Ammodramus caudacutus) in southern Rhode Island. Based on capture-recapture histories of 446 color-banded sparrows studied from 1993 to 1998 at our primary study site, Galilee, we observed significant variation in apparent survival rates among years, but not between sexes. Return rates of adult males (37.6%) and females (35.6%) were not significantly different during any year. Juveniles exhibited high return rates, ranging from 0 to 44%, with males (61% of returns) more likely to return than females (35%). In addition, we monitored movements of 404 color-banded sparrows at nine satellite marshes in 1997 and 1998, which supported our findings at Galilee and documented intermarsh movements by 10% of all banded birds. Lack of gender-bias in adult dispersal and strong natal philopatry of sparrows in Rhode Island occurs regularly among passerines possessing a variety of mating systems. Despite emancipation from parental and resource defense duties, adult male Saltmarsh Sharp-tailed Sparrows exhibited apparent survival rates similar to adult females. Availability of high-quality breeding habitat, which is patchy and saturated, may be the most important factor limiting dispersal for Saltmarsh Sharptailed Sparrows in Rhode Island.
House sparrows (Passer domesticus) have declined world over, with their presence rarely seen in cities. Urbanization has lead to significant changes in the population biology of the species affecting their structure and community composition. We investigated the spatial and temporal distribution of House sparrow in various landscapes and the role of habitat attributes along a gradient of urbanization to uncover their possible sites of nesting and habitat preferences. With the study, we report that urban centres have lost favourable nesting habitats for House sparrows and they have locally migrated to the suburban and rural parts of the city. House sparrow abundance was higher in the suburban landscapes, compared to the rural and urban landscapes. House sparrow in the urban occupied a broader niche breath, than the populations in the sub urban and rural matrix. In the urban, the most preferred habitats of the House sparrow were residential areas with tiled and thatched roofs, in the sub urban, rice mills were most preferred and in the rural landscapes residential areas with tiled and thatched roofs and rice mills were equally preferred by the species. Our results revealed that along the gradient shrub cover, built up cover, socio economic status and economic prosperity were positively related to the abundance of House sparrow populations.
Journal of Field Ornithology, 2017
Black-throated Sparrows (Amphispiza bilineata) are common breeding birds throughout the desert regions of North America and can be considered nest-site generalists. Information about how spatial (e.g., vegetation) and temporal factors influence nest survival of these sparrows is lacking throughout their range. Our objective was to examine the spatial and temporal factors associated with nest survival of Blackthroated Sparrows at the nest and nest-patch scales in the predator-rich environment of the northern Chihuahuan Desert of New Mexico. We used a logistic-exposure model fit within a Bayesian framework to model the daily survival probability of Black-throated Sparrow nests. Predation was the leading cause of nest failure, accounting for 86% of failed nests. We found evidence of negative associations between nest survival and both vegetative cover above nests and shrub density within 5 m of nests. We found no support for other habitat covariates, but did find strong evidence that daily survival rate was higher earlier in the breeding season and during the egg-laying stage. A decline in nest survival later in the breeding period may be due to increased predator activity due to warmer ambient temperatures, whereas lower survival during the incubation and nestling stages could be a result of increased activity at nests. A generalist approach to nest-site selection may be an adaptive response to the presence of a diverse assemblage of nest predators that results in the reduced influence of spatial factors on nest survival for Black-throated Sparrows.
Breeding Bird Abundance in an Urbanizing Landscape in Coastal Southern California
Conservation Biology, 1997
The relative influence of local versus landscape heterogeneity on species abundance is an important consideration in the design and management of nature reserves in heterogeneous landscapes. We described the spatial patterns of resident breeding bird abundance at a landscape scale in an urbanizing landscape gradient in coastal San Diego County, California (USA). The gradient spanned approximately 260 km 2 and included a large, mostly contiguous block of undeveloped shrub habitat mosaic which graded into an area of internally fragmented habitat and finally into an area characterized by discrete patches of habitat in an urban matrix. We quantified the distribution of resident bird species in this landscape with point counts and used stepwise logistic regression and canonical correspondence analysis to explore the relative strengths of association between bird abundance and local habitat variation versus landscape variation for the 20 most common bird species. We measured local habitat conditions in a 100-m radius around each point count station. Landscape variables were extracted from a GIS database of this region and included habitat patch size, distance to developed edge, and two indices of urban exposure. The addition of landscape variables to stepwise logistic regression analyses substantially improved the predictive power of the resulting models in 14 of 20 species. Model concordance (the ability of the model to correctly classify all pairs of divergent sites) increased from a mean of 56% without landscape variables to 76% when one or more landscape variables were selected for inclusion in the final model. Response of the 20 focal species to the landscape gradient differed markedly among species. Canonical correspondence analysis was used to rank species along a landscape response gradient from edge/fragmentation reduced species to edge/fragmentation enhanced species. The four species exhibiting the most edge/fragmentation reduced pattern were sparrows: Sage (Amphispiza belli) , Rufous-crowned (Aimophila ruficeps) , Lark (Chondestes grammacus) , and Black-chinned sparrows (Spizella atrogularis). Costa's Hummingbird (Calypte costae) also showed a pattern of edge/fragmentation reduction. The opposite end of the gradient was occupied by species whose densities are elevated near edges and in fragmented areas. The middle of the gradient was occupied by species that were abundant, widely distributed, and showed no sensitivity to landscape position or shrub habitat type. The abundance of edge/fragmentation reduced species appears to be depressed within 200 to 500 m of an edge and the abundance of the edge/fragmentation enhanced species is elevated up to 1000 m from an edge, depending on the species. Conservation analyses, including GAP analysis, often assume that the relationship between species abundance and habitat is invariant with landscape position. In heterogeneous landscapes these analyses may underestimate the conservation risk to species in the edge/fragmentation sensitive category because their abundance varies strongly with landscape location.
Birds
Urban planning and management need long-term population level studies for evaluating how urbanization influences biodiversity. Firstly, we reviewed the current population trends of the House Sparrow (Passer domesticus) and the Eurasian Tree Sparrow (Passer montanus) in Europe, and evaluated the usefulness of citizens’ science projects to monitor these species in Finland. Secondly, we conducted a long-term (1991–2020) winter field study in 31 urban settlements along a 950 km north–south extent in Finland to study how latitude, weather and urbanization influence on sparrow’s growth rates. The House Sparrow is declining in 15 countries, and increasing in 5, whereas the Eurasian Tree Sparrow is declining in 12 and increasing in 9 European countries. The trend of the House Sparrow was significantly negative in continental Europe. However, the trend of the Eurasian Tree Sparrow was not significant. Both species have declined simultaneously in six countries, whereas in four countries, thei...
Ecoscience, 2011
Bird species are adapted to certain ranges of physical conditions and will respond to environmental heterogeneity depending on their ability to exploit a broad range of resources and their tolerance to new environmental conditions. We used the rufous-collared sparrow as a model to explore how the abundance of generalist passerine birds may vary along environmental gradients in the southern Neotropics. We analyzed variations in the abundance along 6 gradients expressing variations in climate, productivity, the proportion of native forest in the landscape, the proportion of vegetation types through the transition between regions, and the intensity of human activities (agriculture, urbanization). The rufous-collared sparrow was most abundant in seasonal and semi-arid climates. Thermal amplitude was the best climatic predictor of the species abundance at the large scale. Within regions where climatic conditions are relatively homogeneous, land use better predicted abundance patterns. The species responded positively to increasing primary productivity, agricultural intensity, and native forest degradation and conversion and negatively to increasing urbanization. The rufous-collared sparrow adapts successfully to new environments created by human activities such as agriculture, ranching, forestry, and urbanization. Some native species may be tolerant to certain types and intensity of human activities, and knowledge of how they respond to both natural and human-created environments may help efforts to anticipate the impact of human activities on native birds in a changing world.
Annual Survival Rates of Wintering Sparrows: Assessing Demographic Consequences of Migration
The Auk, 2002
The demographic consequences of migration have important implications for both evolutionary ecology and conservation biology. We investigated local survival rates for six populations of sparrows at a wintering site. Recent developments in mark-recapture statistics were applied to a 13 year dataset with large numbers of marked individuals (n ϭ 1,632 to 4,394). The study taxa were closely related, and included one resident species (Song Sparrow [Melospiza melodia gouldii]), one short-distance migrant (''Puget Sound'' White-crowned Sparrow [Zonotrichia leucophrys pugetensis]), two moderate-distance migrants (Lincoln's [Melospiza lincolnii] and Fox [Passerella iliaca] sparrow), and two long-distance migrants (''Gambel's'' White-crowned [Zonotrichia leucophrys gambelii] and Golden-crowned [Zonotrichia atricapilla] sparrow). A literature review demonstrated a cline in fecundity among these sparrows: resident and short-distance migrants laid multiple clutches of few eggs, whereas long-distance migrants tended to produce one large clutch. Annual rates of local survival were low in the interval after first capture (Ͻ0.35), possibly because of variation in true survival, site-fidelity, presence of transients and heterogeneity of capture. Estimates of local survival among birds that returned at least once were more robust and were comparable among Song (0.558 Ϯ 0.054 SE), Puget Sound White-crowned (0.461 Ϯ 0.026), Lincoln's (0.456 Ϯ 0.066), Fox (0.352 Ϯ 0.0), Golden-crowned (0.422 Ϯ 0.023) and Gambel's White-crowned (0.432 Ϯ 0.0) sparrows. Estimates of survivorship for Lincoln's and Fox sparrows are among the first values available for those species. Local survival was not higher among resident than migratory taxa, nor did it covary with migration distance among migratory species. These results did not support the time-allocation hypothesis of Greenberg (1980), but are consistent with aspects of bet-hedging theory. While these analyses have potential implications for conservation of migratory birds, further work is required to establish whether these patterns are applicable to Neotropical migrants.
Factors that influence vital rates of Seaside and Saltmarsh sparrows in coastal New Jersey, USA
Journal of Field Ornithology, 2017
As saltmarsh habitat continues to disappear, understanding the factors that influence saltmarsh breeding bird population dynamics is an important step for the conservation of these declining species. Using five years (2011-2015) of demographic data, we evaluated and compared Seaside (Ammodramus maritimus) and Saltmarsh (A. caudacutus) sparrow apparent adult survival and nest survival at the Edwin B. Forsythe National Wildlife Refuge, New Jersey, USA. We determined the effect of site management history (unditched vs. ditched marsh) on adult and nest survival to aid in prioritizing future management or restoration actions. Seaside Sparrow apparent adult survival (61.6%, 95% CI: 52.5-70.0%) averaged >1.5 times greater than Saltmarsh Sparrow apparent adult survival (39.9%, 95% CI: 34.0-46.2%). Nest survival and predation and flooding rates did not differ between species, and predation was the primary cause of failure for both species. Apparent adult survival and nest survival did not differ between unditched and ditched marshes for either species, indicating that marsh ditching history may not affect breeding habitat quality for these species. With predation as the primary cause of nest failure for both species in New Jersey, we suggest that future research should focus on identification of predator communities in salt marshes and the potential for implementing predator-control programs to limit population declines.
Current Zoology, 2016
Every species has certain habitat requirements, which may be altered by interactions with other co-occurring species. These interactions are mostly ignored in predictive models trying to identify key habitat variables correlated with species population abundance/occurrence. We investigated how the structure of the urban landscape, food resources, potential competitors, predators, and interaction between these factors influence the abundance of house sparrow Passer domesticus and the tree sparrow P. montanus in sixty 25 ha plots distributed randomly across residential areas of the city of Pozna n (Poland). The abundance of the house sparrow was positively correlated with the abundance of pigeons but negatively correlated with human-related food resources. There were significant interaction terms between abundances of other urban species and habitat variables in statistical models. For example, the abundance of house sparrow was negatively correlated with the abundance of corvids and tree sparrows but only when food resources were low. The abundance of tree sparrows positively correlated with density of streets and the distance from the city center. The abundance of this species positively correlated with the abundance of corvids when food resources were low but negatively correlated at low covers of green area. Our study indicates that associations between food resources, habitat covers, and the relative abundance of two sparrow species are altered by the abundance of other urban species. Competition, niche separation and social facilitation may be responsible for these interactive effects. Thus, biotic