Chilean Bird Distribution

Ecology ◽  
1970 ◽  
Vol 51 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Martin L. Cody
Keyword(s):  
Bird Distribution

scholarly journals Current Land Bird Distribution and Trends in Population Abundance Between 1982 and 2012 on Rota, Mariana Islands

2015 ◽  
Vol 6 (2) ◽  
pp. 511-540 ◽  
Author(s):  
Richard J. Camp ◽  
Kevin W. Brinck ◽  
P. Marcos Gorresen ◽  
Fred A. Amidon ◽  
Paul M. Radley ◽  
...  
Keyword(s):  
Land Cover ◽  
Bird Species ◽  
Ratio Estimator ◽  
Occupancy Models ◽  
Tree Sparrow ◽  
Range Restriction ◽  
Widespread Distribution ◽  
Significant Difference ◽  
Eurasian Tree Sparrow ◽  
Bird Distribution

Abstract The western Pacific island of Rota is the fourth largest human-inhabited island in the Mariana archipelago and designated an Endemic Bird Area. Between 1982 and 2012, 12 point-transect distance-sampling surveys were conducted to assess bird population status. Surveys did not consistently sample the entire island; thus, we used a ratio estimator to estimate bird abundances in strata not sampled during every survey. Trends in population size were reliably estimated for 11 of 13 bird species, and 7 species declined over the 30-y time series, including the island collared-dove Streptopelia bitorquata, white-throated ground-dove Gallicolumba xanthonura, Mariana fruit-dove Ptilinopus roseicapilla, collared kingfisher Todiramphus chloris orii, Micronesian myzomela Myzomela rubratra, black drongo Dicrurus macrocercus, and Mariana crow Corvus kubaryi. The endangered Mariana crow (x̄  =  81 birds, 95% CI 30–202) declined sharply to fewer than 200 individuals in 2012, down from 1,491 birds in 1982 (95% CI  =  815–3,115). Trends increased for white tern Gygis alba, rufous fantail Rhipidura rufifrons mariae, and Micronesian starling Aplonis opaca. Numbers of the endangered Rota white-eye Zosterops rotensis declined from 1982 to the late 1990s but returned to 1980s levels by 2012, resulting in an overall stable trend. Trends for the yellow bittern Ixobrychus sinensis were inconclusive. Eurasian tree sparrow Passer montanus trends were not assessed; however, their numbers in 1982 and 2012 were similar. Occupancy models of the 2012 survey data revealed general patterns of land cover use and detectability among 12 species that could be reliably modeled. Occupancy was not assessed for the Eurasian tree sparrow because of insufficient detections. Based on the 2012 survey, bird distribution and abundance across Rota revealed three general patterns: 1) range restriction, including Mariana crow, Rota white-eye, and Eurasian tree sparrow; 2) widespread distribution, low abundance, including collared kingfisher, island collared-dove, white-throated ground-dove, Mariana fruit-dove, white tern, yellow bittern, black drongo, and Micronesian myzomela; and 3) widespread distribution, high abundance, including rufous fantail and Micronesian starling. The Mariana crow was dispersed around the periphery of the island in steep forested land-cover types. In contrast, the Rota white-eye was restricted to the high-elevation mesa. Only for the white-throated ground-dove was there a significant difference among cover types, with lower occupancy in open field than in forested areas. Vegetation was included in the best-fit occupancy models for yellow bittern, black drongo, Micronesian myzomela, and Micronesian starling, but vegetation type was not a significant variable nor included in the top models for the remaining five species: white tern, island collared-dove, Mariana fruit-dove, collared kingfisher, and rufous fantail. Given declining population trends, the Rota bird-monitoring program could benefit from establishing threshold and alert limits and identifying alternative research and management actions. Continued monitoring and demographic sampling, in conjunction with ecological studies, are needed to understand why most bird species on Rota are declining, identify the causative agents, and assess effectiveness of conservation actions, especially for the Mariana crow.

scholarly journals Effect of Expert Opinion on the Predictive Ability of Environmental Models of Bird Distribution

2005 ◽  
Vol 19 (2) ◽  
pp. 512-522 ◽  
Author(s):  
JAVIER SEOANE ◽  
JAVIER BUSTAMANTE ◽  
RICARDO DIAZ-DELGADO
Keyword(s):  
Expert Opinion ◽  
Predictive Ability ◽  
Environmental Models ◽  
Bird Distribution

Estimated Forest Bird Densities by Variable Distance Point Counts

1985 ◽  
Vol 12 (2) ◽  
pp. 307 ◽  
Author(s):  
GH Pyke ◽  
HF Recher
Keyword(s):  
Fixed Time ◽  
Time Interval ◽  
Point Counts ◽  
Fixed Time Interval ◽  
Area Of Interest ◽  
Bird Density ◽  
Significant Movement ◽  
Stationary Observer ◽  
Variable Distance ◽  
Bird Distribution

During variable distance point counts a stationary observer records the species and distance for all birds detected during a fixed time interval. Such counts, repeated throughout the area of interest, can be used to estimate bird density so long as the following assumptions are made: (1) the distribution of birds is unaffected by the observer; (2) observers are certain of detecting near birds; (3) there is no error in measurement or estimation of distances; and (4) birds are stationary. Data collected during the present study indicated that at least two of these assumptions are not satisfied: estimates of distance based on sound are inaccurate and observers do not always detect near birds. No effect of observer presence on bird distribution was detected nor did there appear to be any significant movement of birds during counts. We recommend that bird counts be based only on sight detections and that, when bird movement is significant, instantaneous counts be used.

scholarly journals Changes in bird distribution in a Central European country between 1985–1989 and 2001–2003

2010 ◽  
Vol 151 (4) ◽  
pp. 923-932 ◽  
Author(s):  
Jaroslav Koleček ◽  
Jiří Reif ◽  
Karel Šťastný ◽  
Vladimír Bejček
Keyword(s):  
European Country ◽  
Central European Country ◽  
Central European ◽  
Bird Distribution

Climate and satellite-derived land cover for predicting breeding bird distribution in the Great Lakes Basin

2004 ◽  
Vol 31 (2) ◽  
pp. 315-331 ◽  
Author(s):  
L. A. Venier ◽  
J. Pearce ◽  
J. E. McKee ◽  
D. W. McKenney ◽  
G. J. Niemi
Keyword(s):  
Land Cover ◽  
Great Lakes ◽  
Great Lakes Basin ◽  
Breeding Bird ◽  
Bird Distribution
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