Low reproductive success of the endangered Iberá Seedeater in its only known breeding site, the Iberá Wetlands, Argentina

The Condor ◽  
2021 ◽  
Author(s):  
Melanie Browne ◽  
Sheela P Turbek ◽  
Constanza Pasian ◽  
Adrián S Di Giacomo
Keyword(s):  
Breeding Season ◽  
Migratory Birds ◽  
Nest Survival ◽  
Breeding Site ◽  
Grassland Management ◽  
Nest Site Selection ◽  
Breeding Biology ◽  
Cumulative Probability ◽  
Conservation Area ◽  
Northeastern Argentina

Abstract Subtropical grasslands are highly susceptible to habitat conversion and number among South America’s most threatened ecosystems. The grasslands of northeastern Argentina have been identified as a priority conservation area for threatened capuchino seedeaters because they constitute the main breeding area of these migratory birds. The Iberá Seedeater (Sporophila iberaensis) is a newly described species in the Iberá Wetlands in Argentina whose biology is still poorly understood. The endangered species inhabits grasslands but has only been reported to breed in the Iberá Wetlands ecoregion of northeastern Argentina. To explore the species’ association with grassland vegetation, we studied the breeding biology (clutch size, hatching success, and fledgling production) of the Iberá Seedeater and the main parameters that influence nest survival and nest-site selection. We conducted nest searches and banded adults and nestlings in Iberá National Park during the breeding seasons of 2016–2018. The breeding season of the Iberá Seedeater was highly synchronous and the cumulative probability of nest survival was 0.16. The daily nest survival rate decreased as the breeding season advanced, survival was lower for nests supported by Rhynchospora corymbosa than Paspalum durifolium, the two main nest substrates, and the main causes of nest failure were nest predation and strong winds. Additionally, the population exhibited male-biased site fidelity and a low female return rate. In contrast to other capuchinos, whose breeding biology is associated with upland grasslands, the Iberá Seedeater nested exclusively in flooded lowland grasslands on marsh plants. Thus, effective lowland grassland management is key to maintain the vegetation structure required for reproduction in the Iberá Seedeater.

scholarly journals The Kestrel Falco tinnunculus in Slovenia – a review of its distribution, population density, movements, breeding biology, diet and interactions with other species / Postovka Falco tinnunculus v Sloveniji – pregled njene razširjenosti, populacijske gostote, disperzije, gnezditvene biologije, prehrane in interakcij z drugimi vrstami

Acrocephalus ◽  
2012 ◽  
Vol 33 (152-153) ◽  
pp. 5-24
Author(s):  
Tanja Šumrada ◽  
Jurij Hanžel
Keyword(s):  
Population Density ◽  
Breeding Season ◽  
Residential Buildings ◽  
Breeding Population ◽  
Nest Site Selection ◽  
Breeding Biology ◽  
Population Estimate ◽  
Falco Tinnunculus ◽  
Hunting Behaviour ◽  
Breeding Distribution

The paper discusses the breeding and non-breeding distribution and population density of the Kestrel Falco tinnunculus in Slovenia, its movements, breeding biology, hunting behaviour, diet and interactions with other species. The data were collected from published works and directly from observers. The species’ breeding distribution is shown as a comparison of both national breeding bird atlases, which indicated no convincing changes in its distribution. The non-breeding season population estimate (1,000-2,000 ind.) is lower than the breeding population estimate (1,500-2,000 pairs). The Kestrel breeds at altitudes from 0 to 2,050 m a.s.l.; outside the breeding season, it has been observed at altitudes of up to 1,700 m a.s.l. At least part of the breeding population migrates, apparently more or less towards SSW. The breeding season lasts from February to July. It nests in trees, buildings, cliffs, nestboxes and on electricity pylons. In trees it uses abandoned nests of corvids. On buildings it nests mainly on ledges and in various openings. It often nests on industrial and residential buildings. On cliffs it nests in natural openings and in abandoned nests of other species. It lays 3-9 eggs, usually five. It hunts over open terrain by windhovering, active aerial pursuit and stooping onto the ground from perches. It feeds mainly on small mammals and, to a lesser extent, on passerines, reptiles and invertebrates. It interacts with other species during hunting, nest-site selection and breeding itself. Platyhelminthic, nematode, ixodid and insect parasites have all been recorded on the Kestrel

Observation on the breeding biology of Polypedates teraiensis (Dubois, 1987) (Amphibia: Rhacophoridae)

2017 ◽  
Vol 17 (1) ◽  
pp. 25-32
Author(s):  
Jacinta Lalchhanhimi ◽  
Lalremsanga H.T.
Keyword(s):  
Sexual Dimorphism ◽  
Breeding Season ◽  
Sound Production ◽  
Reproductive Function ◽  
Breeding Biology ◽  
Tree Frog ◽  
University Campus ◽  
Morphometric Measurements ◽  
Advertisement Calls ◽  
Males And Females

The breeding biology of tree frog, Polypedates teraiensis was studied during the breeding season at Mizoram University Campus. It was found that sound production by male during the breeding season was primarily a reproductive function and advertisement calls attract females to the breeding areas and announce other males that a given territory is occupied. The aim of this study was to provide the detailed information on the breeding behaviour and the advertisement calls of Polypedates teraiensis. The morphometric measurements of the amplecting pairs (males and females) for sexual dimorphism along with clutch sizes were also studied.

scholarly journals Preparing for translocations of a Critically Endangered petrel through targeted monitoring of nest survival and breeding biology

Oryx ◽  
2021 ◽  
pp. 1-9
Author(s):  
Johannes H. Fischer ◽  
Heiko U. Wittmer ◽  
Graeme A. Taylor ◽  
Igor Debski ◽  
Doug P. Armstrong
Keyword(s):  
Southern Oscillation ◽  
Nest Survival ◽  
Growth Curves ◽  
Breeding Biology ◽  
Source Population ◽  
Breeding Phenology ◽  
Chick Survival ◽  
Egg Survival ◽  
Dune System ◽  
Burrow Density

Abstract The population of the recently-described Whenua Hou diving petrel Pelecanoides whenuahouensis comprises c. 200 adults that all breed in a single 0.018 km2 colony in a dune system vulnerable to erosion. The species would therefore benefit from the establishment of a second breeding population through a translocation. However, given the small size of the source population, it is essential that translocations are informed by carefully targeted monitoring data. We therefore modelled nest survival at the remaining population in relation to potential drivers (distance to sea and burrow density of conspecifics and a competitor) across three breeding seasons with varying climatic conditions as a result of the southern oscillation cycle. We also documented breeding phenology and burrow attendance, and measured chicks, to generate growth curves. We estimated egg survival at 0.686, chick survival at 0.890, overall nest survival at 0.612, and found no indication that nest survival was affected by distance to sea or burrow density. Whenua Hou diving petrels laid eggs in mid October, eggs hatched in late November, and chicks fledged in mid January at c. 86% of adult weight. Burrow attendance (i.e. feeds) decreased from 0.94 to 0.65 visits per night as chicks approached fledging. Nest survival and breeding biology were largely consistent among years despite variation in climate. Nest survival estimates will facilitate predictions about future population trends and suitability of prospective translocation sites. Knowledge of breeding phenology will inform the timing of collection of live chicks for translocation, and patterns of burrow attendance combined with growth curves will structure hand-rearing protocols. A tuhinga whakarāpopoto (te reo Māori abstract) can be found in the Supplementary material.

The spatial dynamics of White-browed Babbler groups in a fragmented agricultural landscape

2002 ◽  
Vol 8 (4) ◽  
pp. 271 ◽  
Author(s):  
Peter G. Cale
Keyword(s):  
Home Range ◽  
Breeding Season ◽  
Group Dynamics ◽  
Agricultural Landscape ◽  
Local Population ◽  
Breeding Site ◽  
Home Ranges ◽  
Effective Population ◽  
Study Sites ◽  
Group Movements

White-browed Babbler Pomatostomus superciliosus groups occupying linear strips of vegetation had breeding territories that were smaller in area and had longer linear dimensions than those occupying patches. A group's non-breeding home range was larger than its breeding territory. Groups occupying linear/patch home ranges expanded the linear extent and area of their home ranges more than those within other home range configurations. Some groups moved during the non-breeding season and this was more likely to occur if the group occupied a remnant with a low abundance of invertebrates during summer. Some groups that moved returned prior to the next breeding season, but the majority were never seen again. New groups moved into the study sites and established in vacant home ranges. This suggests that those groups that left the study sites may have established new home ranges elsewhere. Breeding site fidelity was lower in groups that had failed in previous breeding attempts. Therefore, group movements were influenced by the feeding and breeding quality of the habitat. However, the configuration of the local population also influenced group movements with those groups on the edge of a local population being more likely to move than those in the interior. New groups were formed by two processes; group dispersal, where groups generally filled a vacant home range, and group budding, which involved the splitting of a large group. Group dispersal maintained group densities while group budding increased the density of groups in a local population. These two processes were common, producing localized fluctuations in the density of groups. Since babbler groups contain only one breeding pair, changes in group density represent changes in effective population size. Therefore, group dynamics may be important to the persistence of local populations of White-browed Babblers, especially in landscapes that have suffered from habitat loss and fragmentation.

scholarly journals Barn Owl (Tyto alba) breeding biology in relation to breeding season climate

2013 ◽  
Vol 155 (1) ◽  
pp. 273-281 ◽  
Author(s):  
Alexandre Chausson ◽  
Isabelle Henry ◽  
Bettina Almasi ◽  
Alexandre Roulin
Keyword(s):  
Breeding Season ◽  
Barn Owl ◽  
Breeding Biology ◽  
Tyto Alba

scholarly journals Greater Sage-Grouse nest bowls buffer microclimate in a post-megafire landscape although effects on nest survival are marginal

The Condor ◽  
2021 ◽  
Vol 123 (1) ◽  
Author(s):  
Christopher R Anthony ◽  
Christian A Hagen ◽  
Katie M Dugger ◽  
R Dwayne Elmore
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Spatial Scales ◽  
Nest Success ◽  
Nest Survival ◽  
Nest Site Selection ◽  
Bare Ground ◽  
Sage Grouse ◽  
Burned Areas ◽  
Visual Obstruction

Abstract Temperature at fine spatial scales is an important driver of nest site selection for many avian species during the breeding season and can influence nest success. Sagebrush (Artemisia spp.) communities have areas with high levels of vegetation heterogeneity and high thermal variation; however, fire removes vegetation that provides protection from predators and extreme environmental conditions. To examine the influence of microclimates on Greater Sage-Grouse (Centrocercus urophasianus) nest site selection and nest success in a fire-affected landscape, we measured black bulb temperature (Tbb) and vegetation attributes (e.g., visual obstruction) at 3 spatial scales (i.e. nest bowl, microsite, and landscape) in unburned and burned areas. Nest bowls exhibited greater buffering of Tbb than both nearby microsites and the broader landscape. Notably, nest bowls were warmer in cold temperatures, and cooler in hot temperatures, than nearby microsites and the broader landscape, regardless of burn stage. Nest survival (NS) was higher for nests in unburned areas compared to nests in burned areas (unburned NS = 0.43, 95% confidence interval [CI]: 0.33–0.54; burned NS = 0.24, 95% CI: 0.10–0.46). The amount of bare ground was negatively associated with NS, but effects diminished as the amount of bare ground reached low levels. Shrub height and visual obstruction were positively associated with NS during the entire study period, whereas minimum Tbb had a weaker effect. Our findings demonstrate that thermoregulatory selection by Greater Sage-Grouse at nest sites had marginal effects on their NS. However, given that increases in vegetation structure (e.g., shrub height) provide thermal refuge and increase NS, vegetation remnants or regeneration in a post-fire landscape could be critical to Greater Sage-Grouse nesting ecology.

Vegetation height and egg coloration differentially affect predation rate and overheating risk: an experimental test mimicking a ground-nesting bird

2012 ◽  
Vol 90 (6) ◽  
pp. 694-703 ◽  
Author(s):  
H. Gillis ◽  
B. Gauffre ◽  
R. Huot ◽  
V. Bretagnolle
Keyword(s):  
Predation Risk ◽  
Breeding Season ◽  
Nest Site Selection ◽  
Artificial Nests ◽  
Vegetation Height ◽  
Selective Pressures ◽  
Wide Range ◽  
Nest Microclimate ◽  
Egg Coloration ◽  
Ground Nesting

Avian eggs need to be laid in protected environments to develop and survive. Nest predation is known as the main cause of breeding failure for many birds, but nest microclimate conditions are also important for embryo development. These two selective pressures are particularly marked in ground-nesting birds. Vegetation height has been shown to be a critical factor for nest-site selection in ground-nesting birds because it can counteract predation and overheating simultaneously. It is therefore difficult to disentangle the respective influences of these risks on selection of a particular nest vegetation height. To develop a conceptual framework for understanding and predicting the relative effects of vegetation on predation and nest microclimate during a breeding season, we used vegetation height to manipulate differentially these two risks. We therefore exposed artificial nests to a wide range of vegetation heights, replicated the experimental tests during spring, and manipulated egg color to estimate predation risk. We confirmed that tall vegetation is relevant to protect unattended eggs against both risks. Whereas predation risk is stable for a given vegetation height, overheating risk presents inter- and intra-seasonal variations. Therefore, over a breeding season, for a given vegetation height, the respective strengths of the two risks are unbalanced and depends on egg coloration. The breeding strategy of ground-nesting birds thus should have been shaped by both selective pressures, but the ultimate choice may depend on the species-specific laying dates and alternative behavioral strategies for protecting the clutch. This study provides new perspectives to investigate avian parental behaviour.

scholarly journals Breeding biology of coppersmith barbet, Megalaima haemacephala (Müller, 1776)

2013 ◽  
Vol 31 ◽  
pp. 31-34
Author(s):  
Noor Jahan Sarker ◽  
M Firoj Jaman ◽  
Shariar Mustafa ◽  
Md Saidur Rahman
Keyword(s):  
Incubation Period ◽  
Breeding Season ◽  
Breeding Success ◽  
Brood Size ◽  
Botanical Garden ◽  
Egg Laying ◽  
Breeding Biology ◽  
Average Weight ◽  
Average Height ◽  
Average Depth

Breeding biology of the Coppersmith barbet, Megalaima haemacephala (Müller, 1776) was carried out between February, 2006 and January, 2007 at Sharawardy Uddyan, Ramna Park, Curzon Hall and National Botanical Garden. The breeding season started from December and ended in June. In total 20 nests were observed, of which 10 nests were studied in details in four study areas. The coppersmith barbet mostly preferred to make holes on the branches of koroi (Albizzia procera) for nesting. Egg laying started on 15th February in the study areas. Average height of nests from the ground was 9.7m and average depth and diameter of the holes was 29.20cm and 4.46cm respectively. New holes were constructed yearly or the old one was reused. Both the sexes took part in incubation of eggs, brooding and feeding to the nestlings. A total of 30 eggs were laid in 10 nests. Clutch size varied from 2 – 4 eggs (average: 3 eggs). Among them, 20 (66.67%) eggs were hatched and the rest 10 (33.33%) were unhatched and lost. Average incubation period was 14 days. The male and the female incubated the eggs for an average of 27.44 minutes/ hours and 32.56 minutes/ hours, respectively. Average number of nestlings (brood size) per nest was 2. Out of 20 nestlings, 16 left their nests successively. The breeding success was 53.33% in relation to the number of eggs laid and 80% in relation to nestlings hatched. The average weight of eggs and nestlings was 3.59g and 9.33g, respectively. The main causes of loss of the eggs and nestlings were human interference, predation and ectoparasitic infections. Insects and fruits were fed to the nestlings by their parents.DOI: http://dx.doi.org/10.3329/ujzru.v31i0.15397Univ. j. zool. Rajshahi Univ. Vol. 31, 2012 pp. 31-34 

Observations on the Breeding Season in Sheep and its Artificial Extension

1944 ◽  
Vol 1944 (02) ◽  
pp. 55-57 ◽  
Author(s):  
John Hammond
Keyword(s):  
Breeding Season ◽  
Grassland Management

Observations on the normal season were made over several years with a small flock of Suffolk X Border Leicester-Cheviot ewes backcrossed with Suffolk rams. The flock was under grassland management ; rams were kept in the whole year round, the fertile ram being usually replaced in the breeding season by a sterile ochred ram. The lambs were left with the ewes until they had ceased to suck. Two ewes have lambed at a time corresponding to service at the end of July or beginning of August ; but the normal season, on the average, extended from mid-September to mid-March, the extremes being the end of August to early April. Ewes suckling lambs born later than July showed slight delay in onset of the breeding season. After lambing in November the interval to the next heat may be as little as three weeks. If ewes are put to the ram at the beginning of the season, so as to lamb down in early February, about half will come on heat again before the end of the season.

scholarly journals How Many Baskets? Clutch Sizes That Maximize Annual Fecundity of Multiple-Brooded Birds

The Auk ◽  
2001 ◽  
Vol 118 (4) ◽  
pp. 973-982 ◽  
Author(s):  
George L. Farnsworth ◽  
Theodore R. Simons ◽  
J. Brawn
Keyword(s):  
Clutch Size ◽  
Breeding Season ◽  
Nest Predation ◽  
Reproductive Effort ◽  
Nest Survival ◽  
Survival Rates ◽  
Season Length ◽  
Deterministic Models ◽  
Cavity Nesting ◽  
Theoretical Issues

Abstract We developed deterministic models on the basis of nest survival rates and renesting behavior capable of predicting annual fecundity in birds. The models calculate probabilities of fledging from one to four nests within a discrete breeding season. We used those models to address theoretical issues related to clutch size. In general, birds require at least one day to lay an egg, and many species delay incubation until their entire clutch is laid. Because it takes longer to complete a larger clutch, and fewer such clutches can fit into a limited breeding season, there exists a clutch size for which annual fecundity is maximized. We asked, for a given amount of reproductive effort (i.e. a set number of eggs), does the age-old maxim “don't put all your eggs in one basket” apply? If so, in how many “baskets” should a nesting bird place its eggs? The answer depends on both likelihood of nest predation and length of the breeding season. Those results are consistent with the observed increase in clutch size with latitude (shorter breeding season length) and larger clutch sizes characteristic of cavity-nesting species (with higher nest survival rates). The models also predict that the size of replacement clutches should decrease as the breeding season progresses, and that intraseasonal decline in clutch size should be more pronounced when the breeding season is short.

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