scholarly journals Nest-Building Effort is Not An Indicator of Male Quality In Bonelli’s Eagles, Aquila fasciata

Author(s):  
José E. Martínez ◽  
Íñigo Zuberogoitia ◽  
José F. Calvo ◽  
Mario Álvarez ◽  
Antoni Margalida

Abstract Raptors often use a variety of materials to build their nests (natural, such as branches, but also non-natural objects), presumably due to their insulating properties, their suitability to advertise occupancy of the nest, and to decrease pathogen and parasite loads. The amount of branches used in a nest is an indicator of parental quality and is often associated with increased breeding success. However, in raptors where both sexes collaborate in nest construction, it is unclear whether the effort expended by males (taking the amount of material carried to the nest as the potential predictor) could constitute an honest signal of parental quality to female conspecifics. We examined data on sex, type of material brought to the nest, breeding experience, timing, and nest-building investment prior to egg-laying from 32 identifiable Bonelli’s Eagles (Aquila fasciata) during the pre-laying period to investigate the relative contribution of the sexes to the amount of nest material gathered. We asked: (1) whether the nest-building investment of males could provide information to the females about their quality; and (2) whether the amount of material delivered to the nest by the male was related to breeding success. Despite the considerable investment of males in nest-building during the pre-laying period, our results indicate that this effort is not a consistent indicator of male quality to the female. Therefore, male nest-building behaviour and investment by Bonelli’s Eagles cannot be considered as an extended expression of their phenotype (an extended phenotypic signal). Nest-building behaviour by males in the early and late stages of nest-building, and the fact that males were not significantly more active builders, are discussed in the contexts of signaling nest occupancy to conspecifics and competitors, the decrease of parasite loads, and the strengthening of the pair-bond during the pre-laying period.

Our Nature ◽  
1970 ◽  
Vol 7 (1) ◽  
pp. 39-47
Author(s):  
A.K. Pramanik ◽  
K.B. Santra ◽  
C.K. Manna

A field study of the nest-building behaviour in the breeding season of the Asian Open-Billed Stork, Anastomus oscitans, was conducted in the Kulik Bird Sanctuary, Raiganj, Uttar Dinajpur, West Bengal, India. Observations were made throughout one complete breeding season (2007-2008) in the sanctuary. The open-billed stork comes in the last week of June at the Kulik bird sanctuary, stays there for 5 to 6 months and leaves the place in the month of December of every year. From the present observations it was noticed that about 58920 storks came to Kulik during 2008. Various types of behaviour were observed during this particular period. Coming to the Kulik, pairing of the individual storks start and mating display was observed within a day or two. Birds of a pair supplied the nest building materials to form the nest.  To give a definite shape to the nest it took about 12-15 days before egg laying. The nesting territory consisted of a semicircle, some times circular and approximately with 30.21 ± 0.12 cm radius. The depth of the nest was about 6.9 ± 0.02 cm. The nest building materials consisted of fragments of old branches of trees, some soft green leaves and grasses. These branches helped in strengthening and the leaves and grasses helped in softening of the nest.  During the incubation period both sexes were involved to incubate the eggs. Nest attendance of the breeding birds was continuous during the first 2-months period. From regular observation it was noticed that either of the pair took additional care by spreading their wings during the time of heavy sunshine or heavy rain. The main behavioral patterns examined were aerial displays, mating pattern, nest building, egg laying and incubation pattern, nest defense and nest protection. Diversity of nesting behavior in open-billed stork was pointed out and discussed.Key words: Asian Open-Billed Stork, Kulik Bird Sanctuary, Nest-building behaviorDOI: 10.3126/on.v7i1.2552Our Nature (2009) 7:39-47


Behaviour ◽  
2012 ◽  
Vol 149 (1) ◽  
pp. 81-98 ◽  
Author(s):  
Michał Gąska ◽  
Przemysław Grela ◽  
Janusz Kloskowski

AbstractIn monogamous birds, early male parental effort, such as nest building, may serve as a post-mating sexually-selected display allowing female assessment of male quality. We examined the functional significance of male nest building and the potential role of nest size as a sexually-selected signal in the red-necked grebe ( Podiceps grisegena), a species with high mate fidelity. Time-activity budgets showed that no behaviour was performed exclusively by one sex in the pre-laying period, but males spent significantly more time nest building and were more often involved in aggressive intra- and interspecific interactions. Nest building in pairs attempting a second brood was also performed predominantly by males. Greater participation in nest construction by males allowed females to allocate more time to self-maintenance activities in the period prior to egg-laying. The positive relationship found between the relative contribution of males to nest building and later to brood provisioning indicates that male nest building is an honest indicator of future paternal effort. Males obtained copulations solicited by females proportionally to the time spent on nest building, and the extent of male participation in nest construction was of importance for explaining variation in clutch size. Nest size itself is not very likely to be sexually selected in red-necked grebes, as it was found to depend on nest site conditions such as water depth and exposure to wave action. We suggest that greater investment of males in energetically demanding pre-laying activities is functionally similar to post-mating courtship feeding; it constitutes males’ indirect contribution to clutch production and may help to negotiate the relative investment each sex makes in the different stages of the breeding cycle. The results support the idea that, in monogamous birds, naturally selected male characters related to parental care may evolve into important sexual signals to females, although not into extreme displays.


2020 ◽  
Author(s):  
Maud Quéroué ◽  
Christophe Barbraud ◽  
Frédéric Barraquand ◽  
Daniel Turek ◽  
Karine Delord ◽  
...  

AbstractAssessing the effects of climate and interspecific relationships on communities is challenging because of the complex interplay between species population dynamics, their interactions, and the need to integrate information across several biological levels (individuals – populations – communities). Usually used to quantify species interactions, integrated population models (IPMs) have recently been extended to communities. These models allow fitting multispecies matrix models to data from multiple sources while simultaneously accounting for various sources of uncertainty in each data source. We used multispecies IPMs accommodating climate conditions to quantify the relative contribution of climate vs. interspecific interactions on demographic parameters, such as survival and breeding success, in the dynamics of a predator-prey system. We considered a stage-structured predator–prey system combining 22 years of capture–recapture data and population counts of two seabirds, the Brown Skua (Catharacta lönnbergi) and its main prey the Blue Petrel (Halobaena caerulea) both breeding on the Kerguelen Islands in the Southern Ocean. Our results showed that climate and predator-prey interactions drive the demography of skuas and petrels in different ways. The breeding success of skuas appeared to be largely driven by the number of petrels and to a lesser extent by intraspecific density-dependence. In contrast, there was no evidence of predation effects on the demographic parameters of petrels, which were affected by oceanographic factors (chlorophyll a and sea surface temperature anomalies). We conclude that bottom-up mechanisms are the main drivers of this skua-petrel system. We discuss the mechanisms by which climate variability and predator-prey relationships may affect the demographic parameters of these seabirds. Taking into account both species interactions and environmental covariates in the same analysis improved our understanding of species dynamics.


2005 ◽  
Vol 22 (3) ◽  
pp. 816-818 ◽  
Author(s):  
Cibele A. Alvarenga ◽  
Sônia A. Talamoni

Descriptions of Sciurus ingrami Thomas, 1901 nests are not available in the literature. In this study, a survey was made of the distribution of S. ingrami nests in a woodlot located near to the headquarters of the Serra do Caraça Reserve, in state of Minas Gerais, where there is a high concentration of Syagrus romanzoffiana (Chamisso) Glassman palm tree, among other exotic tree species. The nest-building behaviour and the nest characteristics, such as height from the ground, total circumference, diameter of the entrance, and the position of the nest in the tree - in the crown, along the trunk or in a side branch, were described.


2013 ◽  
Vol 31 ◽  
pp. 31-34
Author(s):  
Noor Jahan Sarker ◽  
M Firoj Jaman ◽  
Shariar Mustafa ◽  
Md Saidur Rahman

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 


2000 ◽  
Vol 51 (4) ◽  
pp. 355 ◽  
Author(s):  
Peter Dann ◽  
F. I. Norman ◽  
J. M. Cullen ◽  
F. J. Neira ◽  
A. Chiaradia

In May 1995, numbers of little penguins, Eudyptula minor, coming ashore declined at Phillip Island and St Kilda concurrently with deaths of many penguins in western Victoria and a massive mortality of one of their food species (pilchard) throughout southern Australia. Among 1926 dead penguins reported were 131 banded birdsrecovered from Phillip Island (86% adults and 14% first-year birds), 26 from Rabbit Island and six from St Kilda. The number of banded penguins found dead per number of adult Phillip Island birds at risk was 2.3% in 1995 compared with an annual mean of 0.7% for 1970–93. Of 29 corpses autopsied, at least 26 died of starvation associated with mild–severe gastro-intestinal parasitism. Following the pilchard mortality, egg-laying by penguins in the subsequent breeding season (1995–96) was ~2 weeks later than the long-term mean and 0.3 chicks were fledged per pair compared with the long-term mean of 1.0. Unlike previous years, few penguins were recorded in Port Phillip Bay in September–October 1995, a period when pilchard schools were infrequently seen. It is concluded that the increase in penguin mortality in northern Bass Strait and the significant reduction in breeding success were associated with the widespread pilchard mortality.


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