Is the primary helper always a key group for the dynamics of cooperative birds? A mathematical study on cooperative breeding birds

Abstract We studied cooperative-breeding Pygmy Nuthatches (Sitta pygmaea) for 4 yr in northern Arizona. Breeding units contained 2-5 birds. Helpers were found at about 30% of all nests. All helpers that later bred on the study area were male. Helpers were mostly yearlings, and offspring or siblings of the birds that they aided, but often aided at least one unrelated breeder. Breeding units with helpers produced significantly more young than those without helpers. Breeding units in habitats with the greatest floral diversity and structural maturity fledged significantly more young than those in other habitats. Habitat did not influence the effect of helpers. Year effects increased the strength of the relationship between helpers and annual reproductive output. Previous breeding experience and pair-bond duration were not related to reproductive success. Total brood loss, although rare, was responsible for the difference in reproductive output among pairs with and without helpers and between habitats. Breeding birds with helpers benefit by an increase in direct fitness. The advantage to the helpers is not clear but may be an increase in indirect fitness associated with aiding relatives. Helpers may benefit directly, however, by sharing roosting cavities on a group territory thereby enhancing overwinter survival.

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Distribution of the parental care in the Iberian magpie Cyanopica cooki: worker males but lazy helpers?

Behaviour ◽

10.1163/1568539x-00003531 ◽

2019 ◽

Vol 156 (1) ◽

pp. 79-107 ◽

Cited By ~ 1

Author(s):

Carlos de la Cruz ◽

Mónica Expósito-Granados ◽

Juliana Valencia

Keyword(s):

Parental Care ◽

Cooperative Breeding ◽

Feeding Rate ◽

Species Differences ◽

Breeding Birds ◽

Parental Effort ◽

Male And Female ◽

Provisioning Rate ◽

Food Provision ◽

Nestling Feeding

Abstract In many species of cooperative breeding birds, breeders and helpers participate in the parental care with different food provision rules. Normally, helpers feed nestlings less frequently and with smaller quantities of food than breeders. But studies analysing the reaction of feeders to nestling demand are scarce and rarely measure the quantity of food that is actually delivered. In this study, we analysed the provisioning effort of breeders and helpers in the Iberian Magpie, Cyanopica cooki, and how this effort varies with brood demand. We did so by measuring the nestling feeding rate and the biomass supply of each individual. In this way, we obtained a more accurate measurement of the investment assumed by each individual belonging to each status. We found that breeding males visited the nest more often than both breeding females and helpers (mean = 2.24; 0.85 and 1.58, respectively). Furthermore, breeding males delivered more biomass in each feeding visit to the nest than those from other statuses. Breeders, both male and female, increased their parental effort (i.e., provisioning rate and biomass) when brood demand was higher (i.e., more siblings and older nestlings), whereas helpers contributed differently to the nest, but depending on the two types of helpers occurring in this species. Differences in the possible benefits obtained by breeders and helpers may explain these different strategies. In addition, male and female breeders (but not helpers) reduce the feeding rate throughout the breeding season. Thus, in the Iberian magpie, breeders and helpers reveal different patterns of investment depending on nestling food demand.

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Cooperative breeding and the emergence of multilevel societies in birds

10.1101/2021.10.04.462904 ◽

2021 ◽

Author(s):

Ettore Camerlenghi ◽

Alexandra McQueen ◽

Kaspar Delhey ◽

Carly N. Cook ◽

Sjouke A. Kingma ◽

...

Keyword(s):

Social Networks ◽

New Zealand ◽

Cooperative Breeding ◽

Breeding Birds ◽

Cooperatively Breeding ◽

Multilevel Society ◽

Complex Forms ◽

Malurus Cyaneus ◽

Multilevel Societies ◽

Animal Societies

Multilevel societies (MLSs), where social levels are hierarchically nested within each other, are considered one of the most complex forms of animal societies. Although thought to mainly occur in mammals, it is suggested that MLSs could be under-detected in birds. Here we propose that the emergence of MLSs could be common in cooperatively breeding birds, as both systems are favoured by similar ecological and social drivers. We first investigate this proposition by systematically comparing evidence for multilevel social structure in cooperative and non-cooperative birds in Australia and New Zealand, global hotspots for cooperative breeding. We then analyse non-breeding social networks of cooperatively breeding superb fairy-wrens (Malurus cyaneus) to reveal their structured multilevel society, with three hierarchical social levels that are stable across years. Our results confirm recent predictions that MLSs are likely to be widespread in birds and suggest that these societies could be particularly common in cooperatively breeding birds.

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Is the Primary Helper Always a Key Group for the Sustainability of Cooperative Birds? A Mathematical Study on Cooperative Breeding Blue-Tailed Bee-Eater.

10.21203/rs.3.rs-240111/v1 ◽

2021 ◽

Author(s):

Sinchan Ghosh ◽

Fahad Al Basir ◽

Ganesh Chowdhury ◽

Santanu Ray ◽

Sabyasachi Bhattacharya

Keyword(s):

Cooperative Breeding ◽

Migratory Birds ◽

Research Work ◽

Group Living ◽

Breeding Birds ◽

Theory Approach ◽

Test Bed ◽

The Game Theory ◽

The Hierarchical Structure ◽

Living Organisms

Abstract Cooperation is a fundamental requirement for the sustainability of group-living organisms. Despite the substantial research work in cooperative breeding birds, the dependence of the populations' sustainability young or adult helpers in migratory populations is unidentified. The mathematical models for predicting the birds' cooperative dynamics so far mostly ignore the migratory property. The cooperative breeding birds have three groups in their population, viz, immature or primary helpers, mature or secondary helpers, and breeders. We ask three questions to study migratory cooperative birds' sustainability through mathematical modeling under changing environments. Which group is the key to the sustainability of cooperative migratory birds? Does the maturate helper compensate young helpers' helping? Does the hierarchical structure of the population vary for variable migratory rates? We explore the answers based on the mathematical model's simulation experiment, a potential alternative to the game theory approach. This study estimates the parameters associated with the proposed model through the field survey and obtains the rest from existing literature. Although the study uses blue-tailed bee-eater as the test-bed species, the model is useful for analyzing other avian species' behavioral property. The model as a tool can determine whether the primary helpers of blue-tailed bee-eater are the key to sustainability. The model can also classify the adults' help as an addition or compensate to primary helpers' help. The model can predict any alteration in the cooperative breeding birds' hierarchy sizes for variable migration rates under changing climate.

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