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The effect of helpers on reproductive success in the laughing kookaburra

Legge, Sarah

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1. In co-operatively breeding birds and mammals that live in family groups, helpers may gain indirect fitness benefits by increasing the number of breeding attempts in a season, by increasing the success of each nesting attempt, and by increasing the survivorship of related breeders. 2. The effects of helpers were examined in an analysis of reproductive success in the laughing kookaburra (Dacelo novaeguineae), where a monogamously breeding pair is assisted by offspring of both sexes. 3. Helpers...[Show more]

dc.contributor.authorLegge, Sarah
dc.date.accessioned2015-12-13T23:21:05Z
dc.identifier.issn0021-8790
dc.identifier.urihttp://hdl.handle.net/1885/91016
dc.description.abstract1. In co-operatively breeding birds and mammals that live in family groups, helpers may gain indirect fitness benefits by increasing the number of breeding attempts in a season, by increasing the success of each nesting attempt, and by increasing the survivorship of related breeders. 2. The effects of helpers were examined in an analysis of reproductive success in the laughing kookaburra (Dacelo novaeguineae), where a monogamously breeding pair is assisted by offspring of both sexes. 3. Helpers could not increase the number of attempts in a season, because kookaburras are single-brooded. 4. in a paired analysis controlling for pair and territory quality, increases in group size were not matched by increases in the number or weight of fledglings in each breeding attempt, even though brood reduction was the major source of productivity loss. This concurs with previous results showing that group size does not affect overall provisioning levels to broods, because all group members reduced their provisioning effort as group size increased. 5. Because kookaburras prefer to reduce workloads during breeding rather than raise larger broods, the costs of caring for young must be high. Thus breeders with helpers may enjoy energetic savings and enhanced survivorship. 6. Helpers had different effects on nest success depending on their sex. Whereas male helpers had a neutral effect on fledgling success and fledgling weight, additional female helpers reduced fledgling success. Females are relatively poor helpers, and other group members may not properly compensate for the female's 'inadequate' help. 7. High-quality kookaburra pairs, or pairs on good territories, were more likely to be in larger groups because they produced more potential recruits for their groups than relatively 'poor' performers. This was demonstrated by comparing the results of the paired comparisons with those of a correlational analysis that showed that in groups of two to six birds, group size was positively correlated with fledgling success and fledgling weight (which affects the probability of juvenile survival). 8. However, unusually large groups of seven or more birds suffered drastically reduced nest success because eggs were damaged during incubation.
dc.publisherBritish Ecological Society
dc.sourceJournal of Animal Ecology
dc.subjectKeywords: cooperative behavior; cooperative breeding; food provisioning; group size; reproductive success; sex-related difference; Dacelo novaeguineae Co-operative breeding; Costs of helping; Kin selection; Kingfisher; Philopatry
dc.titleThe effect of helpers on reproductive success in the laughing kookaburra
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume69
dc.date.issued2000
local.identifier.absfor060603 - Animal Physiology - Systems
local.identifier.ariespublicationMigratedxPub21521
local.type.statusPublished Version
local.contributor.affiliationLegge, Sarah, College of Medicine, Biology and Environment, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.startpage714
local.bibliographicCitation.lastpage724
local.identifier.doi10.1046/j.1365-2656.2000.00429.x
dc.date.updated2015-12-12T09:05:27Z
local.identifier.scopusID2-s2.0-0033902106
CollectionsANU Research Publications

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