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

2021 ◽  
Author(s):  
JH Fischer ◽  
Heiko Wittmer ◽  
GA Taylor ◽  
I Debski ◽  
DP Armstrong
Keyword(s):  
Southern Oscillation ◽  
Nest Survival ◽  
Growth Curves ◽  
Breeding Biology ◽  
Source Population ◽  
Breeding Phenology ◽  
Chick Survival ◽  
Egg Survival ◽  
Dune System ◽  
Burrow Density

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.

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.

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

2021 ◽  
Author(s):  
JH Fischer ◽  
Heiko Wittmer ◽  
GA Taylor ◽  
I Debski ◽  
DP Armstrong
Keyword(s):  
Southern Oscillation ◽  
Nest Survival ◽  
Growth Curves ◽  
Breeding Biology ◽  
Source Population ◽  
Breeding Phenology ◽  
Chick Survival ◽  
Egg Survival ◽  
Dune System ◽  
Burrow Density

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.

scholarly journals Costs of Egg Punctures and Parasitism by Shiny Cowbirds (Molothrus Bonariensis) at Creamy-Bellied Thrush (Turdus Amaurochalinus) Nests

The Auk ◽  
2006 ◽  
Vol 123 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Andrea A. Astié ◽  
Juan C. Reboreda
Keyword(s):  
Reproductive Success ◽  
Hatching Success ◽  
Nest Survival ◽  
Egg Laying ◽  
Chick Survival ◽  
Egg Survival ◽  
Lower Survival Rate ◽  
Molothrus Bonariensis ◽  
Primary Determinant ◽  
The Cost

AbstractMost studies on cowbird parasitism have focused on its effects on parasitized nests, whereas few have considered the costs at nests that cowbirds visit but at which they do not lay eggs. Shiny Cowbirds (Molothrus bonariensis) peck and puncture host eggs both in nests where they lay eggs and in unparasitized nests. We analyzed the effect of egg punctures in unparasitized and parasitized nests of a large host, the Creamy-bellied Thrush (Turdus amaurochalinus; hereafter “thrush”), as well as the costs of Shiny Cowbird eggs and chicks in this host’s nests. We determined thrush egg survival, hatching success, and chick survival in successful nests, and nest survival during the egg and nestling stages. Frequency of parasitism was 60%, and its intensity 1.6 ± 0.1 eggs nest−1. Number of host eggs punctured was positively associated with intensity of parasitism. The host’s eggs were frequently punctured in parasitized nests (71%) and in unparasitized nests (42%). Egg punctures reduced the number of eggs at hatching in 23% and 49% of unparasitized and parasitized nests, respectively. Nests with egg punctures had a lower survival rate than nests without them, but nest survival was not associated with parasitism. Presence of a Shiny Cowbird egg was associated with a decrease in the hatching success of host eggs, but presence of a Shiny Cowbird chick did not have any detrimental effect on either the survival and growth rate of host chicks in successful nests or the survival of the whole nest. Our results show that egg punctures were the primary determinant of thrush reproductive success. Consequently, comparison of unparasitized and parasitized nests gives an incomplete estimation of the effects of Shiny Cowbirds on host reproductive success, because the cost of egg punctures is also important in nests where there is no Shiny Cowbird egg laying.Costos de la Perforación de Huevos y el Parasitismo por Molothrus bonariensis en Nidos de Turdus amaurochalinus

scholarly journals A Comparative Study of Shiny Cowbird Parasitism of Two Large Hosts, the Chalk-Browed Mockingbird and the Rufous-Bellied Thrush

The Condor ◽  
2003 ◽  
Vol 105 (4) ◽  
pp. 728-736 ◽  
Author(s):  
Paula Sackmann ◽  
Juan Carlos Reboreda
Keyword(s):  
Hatching Success ◽  
Nest Survival ◽  
Host Defenses ◽  
Chick Survival ◽  
Egg Survival ◽  
Brood Parasites ◽  
Molothrus Bonariensis ◽  
Cowbird Parasitism ◽  
Egg Destruction ◽  
Host Parasite

AbstractIt is usually accepted that generalist brood parasites should avoid using hosts larger than themselves because host chicks may outcompete parasite chicks for food. We studied the interactions between the Shiny Cowbird (Molothrus bonariensis) and two common hosts larger than the parasite, the Chalk-browed Mockingbird (Mimus saturninus) and the Rufous-bellied Thrush (Turdus rufiventris). For each host we determined (1) frequency and intensity of parasitism during the breeding season, (2) nesting success, egg survival, hatching success, and chick survival in unparasitized and parasitized nests, and (3) antiparasitic defenses. We also determined Shiny Cowbird egg survival, hatching success, and chick survival in both hosts. Parasitism reached 50% in mockingbirds and 66% in thrushes. In both species the main cost of parasitism was egg destruction through punctures. Hatching success, survival of host chicks, and nest survival did not differ between unparasitized and parasitized nests. Both hosts rejected parasitic white-morph eggs but accepted spotted-morph ones, even though they were significantly smaller than host eggs. The proportion of cowbirds fledged per egg laid in successful mockingbird and thrush nests was 0.4 and 0.6, respectively. Considering nest survival, reproductive success of Shiny Cowbirds was 0.15 in mockingbird nests and 0.17 in thrush nests. These values are similar to or higher than cowbird success with smaller hosts. Our results indicate that host quality is not only determined by host-parasite differences in body size, and that other factors, such as host defenses and nest survivorship, should be considered.Un Estudio Comparado del Parasitismo de Molothrus bonariensis en dos Hospedadores de Gran Tamaño, Mimus saturninus y Turdus rufiventrisResumen. Es aceptado generalmente que los parásitos de cría generalistas deberían evitar utilizar hospedadores de mayor tamaño corporal porque los pichones del hospedador podrían desplazar a sus pichones en la competencia por alimento. Se estudiaron las interacciones entre Molothrus bonariensis y dos hospedadores frecuentes de mayor tamaño que el parásito, Mimus saturninus y Turdus rufiventris. Para cada hospedador se determinó (1) frecuencia e intensidad de parasitismo durante la temporada reproductiva, (2) éxito de nidificación, supervivencia de huevos, éxito de eclosión y supervivencia de pichones en nidos no parasitados y parasitados, y (3) defensas antiparasitarias. También se determinó el éxito reproductivo del parásito en ambos hospedadores. El porcentaje de nidos parasitados fue 50% en Mimus saturninus y 66% en Turdus rufiventris. En ambas especies, el principal costo del parasitismo fue la destrucción de huevos por picaduras. El éxito de eclosión, la supervivencia de pichones y el éxito de nidificación fueron semejantes entre nidos no parasitados y parasitados. Ambos hospedadores rechazaron los huevos parásitos del morfo blanco pero aceptaron los del morfo manchado, si bien éstos fueron de menor tamaño que los del hospedador. La proporción de volantones de Molothrus bonariensis por huevo puesto en nidos exitosos de Mimus saturninus y Turdus rufiventris fue 0.4 y 0.6, respectivamente. Considerando la supervivencia de los nidos, el éxito reproductivo fue 0.15 en Mimus saturninus y 0.17 en Turdus rufiventris. Estos valores son similares o mayores que los reportados para hospedadores de menor tamaño que el parásito. Nuestros resultados indican que la calidad del hospedador no está sólo determinada por las diferencias en tamaño corporal entre el hospedador y el parásito y que otros factores, como defensas del hospedador y supervivencia de los nidos, deberían ser considerados.

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 Mismatches between breeding phenology and resource abundance of resident alpine ptarmigan negatively affect chick survival

2019 ◽  
Vol 9 (12) ◽  
pp. 7200-7212 ◽  
Author(s):  
Gregory T. Wann ◽  
Cameron L. Aldridge ◽  
Amy E. Seglund ◽  
Sara J. Oyler‐McCance ◽  
Boris C. Kondratieff ◽  
...  
Keyword(s):  
Breeding Phenology ◽  
Chick Survival ◽  
Resource Abundance

Changes in oceanographic conditions off northern British Columbia (1983–1999) and the reproduction of a marine bird, the Ancient Murrelet (Synthliboramphus antiquus)

2001 ◽  
Vol 79 (10) ◽  
pp. 1735-1742 ◽  
Author(s):  
Anthony J Gaston ◽  
Joanna L Smith
Keyword(s):  
British Columbia ◽  
Southern Oscillation ◽  
North Pacific Ocean ◽  
Breeding Biology ◽  
Secular Change ◽  
Enso Events ◽  
The North ◽  
Median Date ◽  
Oceanographic Data ◽  
Oceanographic Conditions

We examined variation in breeding-biology parameters for Ancient Murrelets (Synthliboramphus antiquus), marine birds breeding in central Hecate Strait, British Columbia, over the period 1983–1999. Interannual changes were compared with physical oceanographic data (sea-surface temperatures (SSTs) and Southern Oscillation (SO) indices) for surrounding waters. No secular change in oceanographic data for Hecate Strait was detectable for the period considered, which embraced two major (1982–1983, 1997–1998) and three minor El Niño – Southern Oscillation (ENSO) events. SSTs were strongly related to the SO index for the area considered. Breeding-biology data were not available for the 1982–1983 ENSO. The 1997–1998 ENSO had a strong effect on breeding success, reducing the number of chicks per pair from >1.4 to below 1; most of this effect was caused by desertions before incubation began. We found a positive correlation between May SST and the slope of the regression of chick mass at colony departure on a particular date for a given year. This effect may have resulted from the failure of young or otherwise less competent birds to rear young in years of high SSTs. Both the median date of colony departure and chick mass at departure declined over the period of the study, although neither effect was related to changes in the oceanographic variables considered in this study. These trends may relate to longer term changes in oceanographic conditions in the North Pacific Ocean. If they continue, the recent trend towards lower chick masses at colony departure may have adverse effects on recruitment and eventually on Ancient Murrelet populations.

Nest survival and breeding biology of the Puerto Rican Bullfinch (Loxigilla portoricensis) in southwestern Puerto Rico

2013 ◽  
Vol 125 (4) ◽  
pp. 720-730 ◽  
Author(s):  
Amber N. M. Wiewel ◽  
Stephen J. Dinsmore ◽  
Jaime A. Collazo
Keyword(s):  
Puerto Rico ◽  
Puerto Rican ◽  
Nest Survival ◽  
Breeding Biology
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