scholarly journals Birds' nesting parameters in four forest types in the Pantanal wetland

2014 ◽  
Vol 74 (4) ◽  
pp. 890-898 ◽  
Author(s):  
JB Pinho ◽  
MÂ Marini
Keyword(s):  
Nest Predation ◽  
Bird Species ◽  
Nesting Success ◽  
Vegetation Density ◽  
Forest Types ◽  
Dry Forests ◽  
Mato Grosso ◽  
Evergreen Forests ◽  
Pantanal Wetland ◽  
Predation Rates

We tested the heterogeneity/productivity hypothesis with respect to the abundance and richness of birds and the vegetation density hypothesis with respect to birds' nest predation rates, and determined the relative importance of forested vegetation formations for the conservation of birds in the Pantanal. We estimated the apparent nesting success, and the abundance and richness of nesting birds' in four forest types, by monitoring nests during two reproductive seasons in four forested physiognomies (two high productivity/heterogeneity evergreen forests = Cambará and Landi; two low productivity/heterogeneity dry forests = Cordilheira and Carvoeiro) in the Pantanal wetland in Poconé, State of Mato Grosso, Brazil. We found 381 nests of 46 species (35 Passeriformes and 11 non-Passeriformes) in the four forest types. Of these, we monitored 220 active nests belonging to 44 species, 101 during the reproductive season of 2001 and 119 in 2002. We supported the productivity/heterogeneity hypothesis since the two evergreen forests had higher nest abundance and one of them (Cambará) had higher nesting species richness than the dry forests. The number of nests found in each habitat differed with most nests monitored in the Cambará forest (82%), followed by Landi (9%), Cordilheira (6%) and Carvoeiro (3%) forests. The total number of nests monitored was significantly higher in evergreen forests than in dry forests. Also, more species nested in evergreen (37 species) than in dry (16 species) forests. A Correspondence Analysis revealed that only Carvoeiros had a different nesting bird community. The overall apparent nesting success of 220 nests was 26.8%. We did not support the vegetation density hypothesis since nest predation rates were similar between evergreen (73.5%) and dry (70%) forests, and were higher in the Landi (85%) than in the other three forests (69.2 to 72.2%). Our data indicate that Cambará forests seem to be a key nesting habitat for many bird species of the Pantanal. If this local pattern also occurs in other regions of the Pantanal, the use and management of Cambará forests might prove to be important for the conservation of forest birds of this biome. However, conflicting results with other taxonomic groups show that conservation measures for these forests and land use policies should be based on a more complete biodiversity evaluation of the region.

scholarly journals Using birds to set conservation priorities for Pantanal wetland forests, Brazil

2011 ◽  
Vol 22 (2) ◽  
pp. 155-169 ◽  
Author(s):  
JOÃO BATISTA DE PINHO ◽  
MIGUEL ÂNGELO MARINI
Keyword(s):  
Bird Species ◽  
Dry Forest ◽  
Evergreen Forest ◽  
Conservation Priorities ◽  
Forest Types ◽  
Dry Forests ◽  
Point Counts ◽  
Evergreen Forests ◽  
Local Species Richness ◽  
Bird Richness

SummaryThe Pantanal of Brazil, one of the largest wetlands in the world, is suffering severe threats, such as forest and grassland clearance on the surrounding plateau, conversion of forests and savannas for cattle ranching and effects of large development projects. We used richness, abundance and composition of bird species in four forest types to propose conservation priorities for the northern Pantanal. Birds from 11 sites (a total of 41 points) were sampled through point counts and mist-netting. In total 215 species were recorded in the forests. Two evergreen forest types (cambarazal and landi) had higher estimates of bird richness and abundance than two dry forest types (carvoeiro and cordilheira). The evergreen forests also had more species exclusive to them and were more similar to each other than the dry forests. Selection of forests to be conserved in the northern Pantanal should give priority to evergreen forests and secondarily to dry forests. Cambarazal should be the first forests to be conserved. If the Pantanal inundation cycle is altered by the construction of hydroelectric dams or the Paraguay-Paraná waterway, cambarazal and landi may no longer become flooded, decreasing local species richness. Before our recommendations are considered for conservation and management decisions, more studies on other groups of organisms should also be taken into consideration, and similar studies should be conducted in other regions of the Pantanal. Conservation of Pantanal forest birds depends on a deeper understanding of their use of several habitats, stronger protection of the forests with higher diversity, and public policies that guarantee the long term maintenance of natural flooding cycles.

Effect of partial cutting on predation risk to artificial bird nests

1999 ◽  
Vol 29 (12) ◽  
pp. 1911-1915 ◽  
Author(s):  
J Douglas Steventon ◽  
Peter K Ott ◽  
Kenneth L MacKenzie
Keyword(s):  
Predation Risk ◽  
Nest Predation ◽  
Basal Area ◽  
Predation Rate ◽  
Nesting Success ◽  
Partial Cutting ◽  
Artificial Nests ◽  
Detectable Difference ◽  
Predation Rates ◽  
Rule Out

Based on relative abundance data, partial cutting has been suggested as a technique to maintain habitat for birds associated with late-seral forests, but there has been little study of partial cutting effects on nesting success. One of the primary limitations to nesting success is nest predation. We compared predation rates (proportion of nests disturbed in a 14-day period) in partially cut (30 or 60% basal area removal), clearcut, and uncut forests in northwestern British Columbia, in two experiments using ground-placed (1993) and shrub-placed (1998) artificial nests. In the ground-nest experiment there was a very low predation rate (0.06) and no detectable difference among treatments (p = 0.403). In the shrub-nest experiment, there was a 0.36 predation rate and little evidence of treatment differences (p = 0.295). Based on 90% confidence intervals for differences in observed predation rate, the 30% removal clearly did not increase predation risk relative to uncut forest. With the 60% removal, however, we cannot rule out a possible increase in predation risk compared with either uncut forest or clearcuts.

Conservation Value to Birds of Remnants of Melaleuca Forest in Suburban Brisbane.

1994 ◽  
Vol 21 (4) ◽  
pp. 433 ◽  
Author(s):  
DR Grover ◽  
PJ Slater
Keyword(s):  
Species Composition ◽  
Forest Fragmentation ◽  
National Park ◽  
Bird Species ◽  
Habitat Diversity ◽  
Conservation Value ◽  
Melaleuca Quinquenervia ◽  
Vegetation Density ◽  
Forest Types ◽  
Understorey Vegetation

The bird species composition of nine remnants of Melaleuca quinquenervia forest in NE Brisbane, Queensland, was censused from March 1992 to March 1993 to investigate the effect of forest fragmentation and fragment characteristics. Remnant area was a correlated with the total number of bird species and the number of raptors occurring, while understorey vegetation density was related to the number of forest and understorey bird species. The species composition of the M. quinquenervia remnants was compared with that of the Cooloola National Park and with that of eucalypt [Eucalyptus] remnants in lowland SE Queensland. Even the small M. quinquenervia remnants around Brisbane play an important role in conserving the avian fauna of the region by providing habitat and refuges for migrant, nesting, locally rate and uncommon species, and species not commonly found in other forest types. Future recommended management involves the maintenance of size, habitat diversity and understorey vegetation density, the prevention of disturbance and the preservation of swampy areas and ponds.

scholarly journals Predation Rates on Real and Artificial Nests of Grassland Birds

The Auk ◽  
2000 ◽  
Vol 117 (1) ◽  
pp. 147-153 ◽  
Author(s):  
William B. Davison ◽  
Eric Bollinger
Keyword(s):  
Nest Predation ◽  
House Sparrow ◽  
Grassland Birds ◽  
Passer Domesticus ◽  
Northern Bobwhite ◽  
Nesting Success ◽  
Artificial Nests ◽  
Central Illinois ◽  
Over Time ◽  
Predation Rates

AbstractWe estimated nesting success at real and artificial nests of grassland birds to test the influence of nest type, nest position, and egg size on predation rates. We distributed wicker nests and realistic woven-grass nests baited with a clay egg and either a Northern Bobwhite (Colinus virginianus) egg or a House Sparrow (Passer domesticus) egg in four grasslands that were part of the Conservation Reserve Program in east-central Illinois. Nesting success averaged 86.5% for 12 days of exposure for artificial nests. For real nests, nesting success was markedly lower, averaging 39% over the entire nesting cycle and 59% during approximately 12 days of incubation. Wicker nests were depredated more often than woven-grass artificial nests (18% vs. 8%), and nests baited with House Sparrow eggs were depredated more often than nests baited with Northern Bobwhite eggs (22% vs. 9%). Elevated and ground nests were depredated at the same rate. Patterns of nest predation on wicker nests were markedly different from depredation patterns on real nests over time and among fields. In contrast, patterns of nest predation on realistic woven-grass nests corresponded much more closely with predation rates of real nests over time and among fields. We suggest that future artificial nest studies use nests and eggs that mimic as closely as possible the real nests and eggs of target species. Use of unrealistic artificial nests and eggs, at least in grasslands, may result in patterns of predation that do not accurately reflect those of real nests. Artificial nests of any type appear to underestimate predation rates on nests of grassland birds, possibly because of a lack of snake predation on artificial nests.

Spatial ecology of Western Ratsnakes (Pantherophis obsoletus) : implications for bird nest predation

2014 ◽  
Author(s):  
◽  
Andrew D. George
Keyword(s):  
Nest Predation ◽  
Resource Selection ◽  
Activity Patterns ◽  
Bird Species ◽  
Thermal Conditions ◽  
Weather Data ◽  
Near Surface ◽  
Bird Nest ◽  
Nest Predator ◽  
Predation Rates

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] In fragmented Midwestern forests, many birds face high rates of nest predation, to the point where this region may serve as a population sink for some species. That is, so many of their eggs and young are eaten by predators that these birds cannot produce enough offspring to replace themselves, rendering regions like central Missouri a drain on some bird populations. One important difference between fragmented and contiguous forests (e.g., the Ozarks of southern Missouri where birds seem to be doing better) is that for some bird species, western ratsnakes (Pantherophis obsoletus) are by far the most important nest predator in the fragmented forests. Nest predation rates have been indirectly linked to ratsnake activity patterns or habitat, and recent nest camera studies have directly attributed nest predation by ratsnakes to increased forest fragmentation and weather conditions that are likely favored by ratsnakes. We conducted a large-scale radio-telemetry study of ratsnakes to evaluate their activity patterns and resource selection in study sites where they have been identified as the predominant bird nest predator. First, we used local weather data to model seasonal ratsnake movements as they relate to bird nesting phenology and climate change. Next, we used spatio-temporal temperature models to investigate the thermal conditions available to snakes. We used remote temperature sensors and high-resolution spatial data to develop a dynamic temperature surface for our study area. Models predicted near-surface air temperatures with high accuracy during the winter and growing season, and permitted us to include thermal conditions in resource selection models. Finally, we used discrete choice models to evaluate and predict ratsnake resource selection. We found strong evidence that ratsnakes preferentially select forest-field edges and other habitats that provide structural heterogeneity. Our findings support the hypothesis that edge effects explain increased predation rates in Midwestern forest fragments.

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

scholarly journals Do Repugnant Scents Increase Survival of Ground Nests? A Test with Artificial and Natural Duck Nests

2007 ◽  
Vol 121 (2) ◽  
pp. 150
Author(s):  
Vanessa B. Harriman ◽  
Justin A. Pitt ◽  
Serge Larivière
Keyword(s):  
Human Hair ◽  
Nest Predation ◽  
Survival Rates ◽  
Olfactory Cues ◽  
Artificial Nests ◽  
Treatment Groups ◽  
Mammalian Predators ◽  
High Predation ◽  
Ground Nesting ◽  
Predation Rates

Ground-nesting birds typically experience high predation rates on their nests, often by mammalian predators. As such, researchers and wildlife managers have employed numerous techniques to mitigate nest predation. We investigated the use of scents as repellents to deter predators from both artificial and natural ground nests. Survival rates of artificial nests did not differ among six groups of substances (Wald ?2 df = 5 = 4.53, P < 0.48); however the chronology of predation among groups differed. A commercial Coyote urine based deterrent (DEER-D-TERTM), human hair, and Worcestershire sauce were depredated faster than the control (F4,5 = 40.3, P < 0.001). Nest survival of natural nests differed among those groups tested (Wald ?2 df = 2 = 11.8, P < 0.005); the eight mothball treatment decreased survival (Wald ?2 df = 1 = 11.5, P < 0.005), which indicated that novel smells may attract predators or result in duck nest abandonment when coupled with natural duck scent. Chronologies of predation events among treatment groups were not different for natural nests (F2,3 = 1.9, P = 0.22). These findings indicate an interaction between novel scents and predator olfactory cues.

scholarly journals First record of Trypanosoma sp. (Protozoa: Kinetoplastida) in tuvira (Gymnotus aff. inaequilabiatus) in the Pantanal wetland, Mato Grosso do Sul State, Brazil

2011 ◽  
Vol 20 (1) ◽  
pp. 85-87 ◽  
Author(s):  
Santiago Benites de Pádua ◽  
Márcia Mayumi Ishikawa ◽  
Fabiana Satake ◽  
Gabriela Tomas Jerônimo ◽  
Fabiana Pilarski
Keyword(s):  
Prevalence Rate ◽  
First Record ◽  
Diagnostic Methods ◽  
Mato Grosso ◽  
First Report ◽  
Paraguay River ◽  
Blood Smears ◽  
Mato Grosso Do Sul ◽  
Pantanal Wetland ◽  
Blood Centrifugation

The blood infection by Trypanosoma sp. in tuvira (Gymnotus aff. inaequilabiatus) from the Pantanal wetland was reported in this study. Ten fish from the Paraguay River in the Pantanal were evaluated for the presence of hemoflagellates. Trypomastigotes of Trypanosoma sp. were observed in blood smears from three fish (30% prevalence) and some forms were seen to be undergoing division. Using the diagnostic methods of fresh examination and blood centrifugation in hematocrit capillary tubes, the prevalence rate was 80%. This is the first report of Trypanosoma sp. in tuvira in Brazil.

scholarly journals Bird communities in three forest types in the Pernambuco Centre of Endemism, Alagoas, Brazil

2013 ◽  
Vol 103 (2) ◽  
pp. 85-96 ◽  
Author(s):  
Lahert W. Lobo-Araújo ◽  
Mário T. F. Toledo ◽  
Márcio A. Efe ◽  
Ana C. M. Malhado ◽  
Marcos V. C. Vital ◽  
...  
Keyword(s):  
Species Richness ◽  
Bird Species ◽  
Bird Communities ◽  
Northeastern Brazil ◽  
Forest Fragments ◽  
Forest Types ◽  
Risk Of Extinction ◽  
Bird Fauna ◽  
Richness Patterns ◽  
Ombrophilous Forest

The Pernambuco Center of Endemism (PCE) in northeastern Brazil is highly fragmented and degraded. Despite its potential conservation importance the bird fauna in this area is still relatively unknown and there are many remnant fragments that have not been systematically surveyed. Here, we report the results of bird surveys in five forest fragments (one pioneer, two ombrophilous and two seasonal). In total, 162 taxa were recorded, 12 of which are endemic to the PCE. The frequency of endangered species was lower than what has been reported in studies from the same area and most of the taxa considered to be at risk of extinction were sub-species of uncertain taxonomic validity. The comparatively low number of endemic/threatened species may be due to the small size of the fragments in the present study - a consequence of the high levels of habitat loss in this region. Analysis of species richness patterns indicates that ombrophilous forest fragments are acting as refuges for those bird species that are most sensitive to environmental degradation.

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