Monitoring Bird Populations by Point Counts

1997 ◽  
Vol 61 (4) ◽  
pp. 1453 ◽  
Author(s):  
David G. Krementz ◽  
C. J. Ralph ◽  
J. R. Sauer ◽  
S. Droege
Keyword(s):  
Point Counts ◽  
Bird Populations

Monitoring Bird Populations by Point Counts C. John Ralph John R. Sauer S. Droege

The Auk ◽  
1997 ◽  
Vol 114 (4) ◽  
pp. 811-813
Author(s):  
Bertin W. Anderson
Keyword(s):  
Point Counts ◽  
Bird Populations

scholarly journals Landscape associations of globally threatened grassland birds in the Aguapey river Important Bird Area, Corrientes, Argentina

2009 ◽  
Vol 20 (1) ◽  
pp. 62-73 ◽  
Author(s):  
ADRIAN S. DI GIACOMO ◽  
PETER D. VICKERY ◽  
HERNAN CASAÑAS ◽  
OSCAR A. SPITZNAGEL ◽  
CHRISTIAN OSTROSKY ◽  
...  
Keyword(s):  
River Basin ◽  
Grassland Birds ◽  
Livestock Grazing ◽  
Tall Grass ◽  
Point Counts ◽  
Landscape Characteristics ◽  
Bird Populations ◽  
Management Actions ◽  
Land Use Plan ◽  
Near Threatened

SummaryThe Aguapey river basin in the Pampas grasslands of Argentina is the last refuge for a complete assemblage of globally threatened and Near Threatened birds. We evaluated the influence of landscape characteristics on the occurrence and abundance of six globally threatened and Near Threatened passerines. We used point counts to census birds and vegetation and quantified landscape characteristics 1,000 m from the count centres using remote sensing tools. Strange-tailed Tyrants Alectrurus risora were associated with higher percentages of tall-grass Andropogon lateralis in lowland areas. Saffron-cowled Blackbirds Xanthopsar flavus and Black-and-white Monjitas Heteroxolmis dominicana were associated with rolling landscape with wet lowland grasslands and marshes linked with dry upland grasslands. Marsh Seedeater Sporophila palustris and Chestnut Seedeater S. cinnamomea were associated with tall grasslands and marshes. Rufous-throated Seedeater S. ruficollis was not clearly associated with any type of habitat. The Aguapey grasslands are used mainly for livestock grazing and afforestation. Since 1995, approximately 50% of the original grassland habitat has been planted with exotic trees. If this trend continues, Saffron-cowled Blackbirds are likely to become extinct in the Aguapey river basin which currently supports the largest population of this species in Argentina. We recommend guidelines for establishing future reserves and wildlife management actions based on the landscape responses detected in this study. Future action should consider: maintaining connectivity between the Aguapey grasslands and the Ibera Nature Reserve, creating a protected area, designing a land use plan for the basin, avoiding afforestation in large blocks, removal of government incentives for large afforestation projects, and studying the viability of threatened bird populations in extensive cattle ranching areas.

scholarly journals Temporal changes in bird communities in areas with different histories of fire disturbance in highland grasslands of Brazil

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243070
Author(s):  
Eduardo Chiarani ◽  
Maurício Bettio ◽  
Carla Suertegaray Fontana
Keyword(s):  
Bird Community ◽  
Temporal Changes ◽  
Bird Communities ◽  
Fire Disturbance ◽  
Habitat Modification ◽  
Management Tool ◽  
Southern Brazil ◽  
Point Counts ◽  
Bird Populations ◽  
Minimum Interval

Despite the importance and ubiquity of grasslands, the degradation and the loss of these habitats have negatively affected bird populations throughout the world. The use of fire to manage grassland areas in some regions of southern Brazil can help to maintain these areas but can also influence the bird community in different ways. We assessed temporal changes in richness, abundance, and composition of bird communities in areas with different histories of fire disturbance in highland grasslands of southern Brazil, the most extensive remnant of grassland of the Atlantic Forest domain. We censused birds during four breeding seasons (2015–2018), through point counts in areas burned only once in the last ten years (OF, n = 3), areas burned annually (AF, n = 2), and areas without fire in the last ten years (WF, n = 2). In OF the richness, abundance, and species composition changed in the year of the fire, compared to the previous year, and returned to the initial values two years later. In AF and WF we found some differences among the years, but not with an equally clear pattern. Three of the six grassland associated species assessed individually for density responded significantly to temporal habitat modification since the fire. Our results show that two years without fire were enough time for the bird community to recover after a fire, but some responses are species-specific. Therefore, fire can be used as a management tool for grasslands and may help in the conservation of birds of southern Brazil, as long as with a minimum interval between fires in an area is guaranteed.

scholarly journals Evaluation of Accuracy and Precision of the Sound-Recorder-Based Point-Counts Applied in Forests and Open Areas in Two Locations Situated in a Temperate and Tropical Regions

Birds ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 351-361
Author(s):  
Michał Budka ◽  
Kinga Kułaga ◽  
Tomasz Osiejuk
Keyword(s):  
Habitat Type ◽  
Time Of Day ◽  
Tropical Regions ◽  
Point Count ◽  
Point Counts ◽  
Bird Populations ◽  
Count Method ◽  
Accuracy And Precision ◽  
Geographical Regions ◽  
Point Count Method

The point-count method is one of the most popular techniques for surveying birds. However, the accuracy and precision of this method may vary across various environments and geographical regions. We conducted sound-recorder-based point-counts to examine the accuracy and precision of the method for bird biodiversity estimation as a function of geographical region, habitat type and the time of day at which the survey began. In temperate (Poland) and tropical (Cameroon) regions, we recorded soundscapes on two successive mornings at 36 recording sites (18 in each location). At each site, we analyzed three 5-min surveys per day. We found no differences in the accuracy and precision of the method between regions and habitats. The accuracy was significantly greater at sunrise than during later surveys. The similarity of the bird assemblages detected by different surveys did not differ between regions or habitats. However, the bird communities described at the same time of day were significantly more similar to each other than those detected by surveys conducted at different times. The point-count method provided statistically indistinguishable estimates of bird biodiversity in different geographical regions and habitats. However, our results highlight two weaknesses of the method: low accuracy (41–54%), which limits the usefulness of a single survey in understanding bird–environment relationships, and changes in accuracy throughout the day, which may result in the misinterpretation of the status of bird populations.

scholarly journals Population status of four endemic land bird species after an unsuccessful rodent eradication on Henderson Island

2018 ◽  
Vol 29 (1) ◽  
pp. 124-135 ◽  
Author(s):  
ALEXANDER L. BOND ◽  
M. DE L. BROOKE ◽  
RICHARD J. CUTHBERT ◽  
JENNIFER L. LAVERS ◽  
GREGORY T.W. MCCLELLAND ◽  
...  
Keyword(s):  
Bird Species ◽  
Population Estimate ◽  
Reed Warbler ◽  
Temporary Reduction ◽  
Point Counts ◽  
Beneficial Effects ◽  
Bird Populations ◽  
South Pacific Ocean ◽  
Rodent Eradication ◽  
Land Bird

SummaryInvasive rodents detrimentally affect native bird species on many islands worldwide, and rodent eradication is a useful tool to safeguard endemic and threatened species. However, especially on tropical islands, rodent eradications can fail for various reasons, and it is unclear whether the temporary reduction of a rodent population during an unsuccessful eradication operation has beneficial effects on native birds. Here we examine the response of four endemic land bird species on subtropical Henderson Island in the Pitcairn Island Group, South Pacific Ocean, following an unsuccessful rodent eradication in 2011. We conducted point counts at 25 sampling locations in 14 survey periods between 2011 and 2015, and modelled the abundance trends of all species using binomial mixture models accounting for observer and environmental variation in detection probability. Henderson Reed Warbler Acrocephalus taiti more than doubled in abundance (2015 population estimate: 7,194-28,776), and Henderson Fruit Dove Ptilinopus insularis increased slightly between 2011 and 2015 (2015 population estimate: 4,476–10,072), while we detected no change in abundance of the Henderson Lorikeet Vini stepheni (2015 population estimate: 554–3014). Henderson Crake Zapornia atra increased to pre-eradication levels following anticipated mortality during the operation (2015 population estimate: 4,960–20,783). A temporary reduction of rat predation pressure and rat competition for fruit may have benefitted the reed warbler and the fruit dove, respectively. However, a long drought may have naturally suppressed bird populations prior to the rat eradication operation in 2011, potentially confounding the effects of temporary rat reduction and natural recovery. We therefore cannot unequivocally ascribe the population recovery to the temporary reduction of the rat population. We encourage robust monitoring of island biodiversity both before and after any management operation to better understand responses of endemic species to failed or successful operations.

scholarly journals Decadal persistence of frugivorous birds in tropical forest fragments of northern Paraná

2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Tiago Zaiden ◽  
Fernanda Cristina Marques ◽  
Hugo Reis Medeiros ◽  
Luiz dos Anjos
Keyword(s):  
Bird Species ◽  
The Other ◽  
Forest Fragments ◽  
Forest Fragment ◽  
Frugivorous Birds ◽  
Point Counts ◽  
Bird Populations ◽  
Frugivorous Bird ◽  
Line Transects ◽  
Extinction Events

Forest fragmentation is a major cause of loss of species. We evaluated the local extinction of medium-large frugivorous bird species in six forest fragments of northern Paraná: the Parque Estadual Mata dos Godoy (PEMG), the largest and most preserved forest fragment in the region, and five other fragments. Fixed-width point counts and line transects were conducted along trails in the PEMG for 10 days: from September 2010 to March 2011, and from August 2011 to November 2011. Avian surveys in each of the other forest fragments were made over four days from October to December 2011. We compared data with a previous census carried out 10 years earlier. No extinction events were recorded from the PEMG. However, the relative abundance of species significantly changed during the ten years between surveys. In all the other forest fragments at least two frugivorous bird species disappeared, and in some as many as seven. Protecting the PEMG is crucial for the maintenance of frugivorous bird populations in our studied landscape.

Monitoring bird populations by point counts

1995 ◽  
Author(s):  
C. John Ralph ◽  
John R. Sauer ◽  
Sam Droege
Keyword(s):  
Point Counts ◽  
Bird Populations

Die Brutvogelfauna eines Nadelwaldes der nördlichen Voralpen nach dem Sturm Lothar

2017 ◽  
Vol 168 (2) ◽  
pp. 59-66
Author(s):  
Pierre Mollet ◽  
René Hardegger ◽  
Res Altwegg ◽  
Pius Korner ◽  
Simon Birrer
Keyword(s):  
Forest Succession ◽  
Coniferous Forest ◽  
Bird Species ◽  
Individual Species ◽  
Mountain Forest ◽  
Breeding Bird ◽  
Point Counts ◽  
Federal Institute ◽  
Central Switzerland ◽  
Bird Fauna

Breeding bird fauna in a coniferous forest in the northern Prealps after storm Lothar In a 70-hectare large coniferous forest located on the northern edge of the Alps in central Switzerland, Canton of Obwalden, at an altitude of 1260 to 1550 metres above sea level, we surveyed the local breeding bird fauna in 2002 and 2013 by means of point counts as well as additional area searches for rare species. In December 1999, hurricane Lothar caused two large windthrow areas and several smaller areas with scattered throws in the survey range. We found a total of 48 breeding bird species, which is a very diverse species composition for a mountain forest. In the eleven years between surveys, a decline in distribution or abundance was recorded for four species, while seven species showed an increase; a further four species showed no change. For the remaining species, the data sets were too small to reliably estimate changes. A comparison with forest structure data provided by the Swiss Federal Institute of Forest, Snow and Landscape Research WSL revealed that for five bird species, the changes in distribution or abundance could be explained at least partially by forest succession. In order to obtain realistic distribution and abundance values in this kind of breeding bird survey, it is essential to collect large enough samples and to consider the detection probability of each individual species using appropriate statistical methods.

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