Social organisation and breeding biology of the White-shouldered Fairywren (Malurus alboscapulatus)

Abstract

The White-shouldered Fairywren (Malurus alboscapulatus) is a tropical passerine bird distributed across much of New Guinea. White-shouldered Fairywrens are among few species of fairywren with exclusively tropical distributions and differ from better studied congeners in Australia because subspecies vary by female, but not male, coloration and morphology. As with many bird species in New Guinea, basic demographic, social, morphological, and breeding data are limited. From 2011 to 2018 we documented the basic biology of two subspecies representing extremes of the female ornamentation spectrum. Both subspecies form groups having an even operational sex ratio and appear to breed year-round. Extra-pair paternity occurs in the subspecies with female ornamentation; comparable data are lacking for the subspecies having unornamented females, but the greater scaled cloacal protuberance volume of males suggests similar or higher extra-pair paternity rates. Females of the ornamented subspecies are generally larger than those lacking ornamentation, but exhibit reduced tail lengths, which is thought to serve as a signal of social dominance in other fairywrens. After first achieving adult-like plumage, males and ornamented females retain ornamented plumage year-round; however, only males in the subspecies with unornamented females appear to exhibit delayed plumage maturation. Our discussion highlights similarities and differences between White-shouldered Fairywren life histories and those of better studied Australian Malurus species; we focus on tropical vs. temperate environments and variable female ornamentation, and we identify priorities for future research.

Plumage iridescence is associated with distinct feather microbiota in a tropical passerine

“…However, species-specific feather microorganisms that are able to produce antimicrobial substances 31 , or particular chemical substances contained in preen gland secretions 77–79 may also affect feather microbiota diversity. Our data show that iridescent individuals originating from two geographically (>1000 km apart) and ecologically distinct populations 63 do not differ in feather microbial diversity and harbor similar microbial communities on their feathers. Due to the similarity in microbial communities between individuals living in different environments, it is unlikely that horizontal transmission of microbes from the environment drive differences we observe in microbiota communities.…”

“…a . lorentzi are brown dorsally and white ventrally 63 (“brown individuals” hereinafter), adult males are black with white shoulder patches including an iridescent blue satin sheen. In contrast, males and females of M .…”

Testosterone induces a female ornament followed by enhanced territoriality in a tropical songbird

“…We assessed whether elevated circulating testosterone stimulates ornamentation and the associated behavioral phenotype in female White-shouldered Fairywrens (Malurus alboscapulatus), a species with discrete female plumage phenotypes that differ in ornamentation and territorial defense behavior across subspecies (Enbody et al 2018;Enbody et al 2019). We show experimentally that exogenous testosterone caused unornamented females to produce some plumage ornamentation (predominantly shoulder patches; Fig.…”

“…Individuals who were previously unbanded were given a unique Australian Bird and Bat Banding Scheme metal band in addition to a unique combination of three plastic color bands. White-shouldered Fairywrens nest year-round (Enbody et al 2019), so in order to mitigate the confounding effects of breeding stage on behavior we excluded females who were actively nesting from the experiment.…”

Ornithology of New Guinea and the Indo-Pacific Islands: introduction to the special issue ofEmu – Austral Ornithologyand a dedication to Paul Igag

“…One group, the malurids (fairy-wrens and allies) are a model for the study of co-operative breeding and behavioural ecology (Buchanan and Cockburn 2013). Present mostly in Australia, the family has a few no less fascinating species in New Guinea and one paper here highlights the remarkable biology of one of the species (Enbody et al 2019). Sadly not featured here, but which must be mentioned both for their uniqueness and their global reach to ornithologists and behavioural ecologists, are the birds-of-paradise, bowerbirds and satinbirds.…”