Breeding of an Island-endemic Bird: the New Zealand Whitehead <i>Mohorn albicilla</i>; Pachycephalinae

McLean, Ian; Gill, B. J.

doi:10.1071/mu9880177

Cited by 8 publications

(6 citation statements)

References 7 publications

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“…Even when we found a failed nest, we could not always tell if predation caused the loss, as stoats leave little sign of having killed mohua. We assumed that the secondary causes of nest loss, apart from predation by stoats, were the same in each study area (e.g., predation by longtailed cuckoos (Eudynamis taitensis) and moreporks (Ninox novaeseelandiae), accidents and abandonment, and possibly interference by other mohua- McLean & Gill 1988;Elliott 1990). Standardised 5 min counts of all bird species in the trapped and unlrappcd areas (from August and October 1990, authors' unpubl.…”

Section: Assessing the Effectiveness Of Trappingmentioning

confidence: 99%

Control of a stoat (Mustela erminea) population irruption to enhance mohua (yellowhead) (Mohoua ochrocephala) breeding success in New Zealand

O’Donnell¹,

Dilks²,

Elliott

1996

New Zealand Journal of Zoology

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The mohua or yellowhead (Mohoua ochrocephala) is an endangered, hole-nesting forest bird endemic to New Zealand. Mohua suffer periodic population crashes due to severe predation by the introduced stoat (Mustela erminea). In 1990, a stoat population irruption provided an opportunity to reassess the impact of stoat predation on mohua and to test two linked hypotheses: that adaquate control of stoats by trapping is possible, and that it is a viable management option to assist mohua recovery. The primary experiment (summer 1990/91) was repeated in the summers of 1991/92 and 1992/93 when stoat numbers were lower. Mohua productivity and adult female mortality were compared in two study areas, one trapped and one untrapped, in the Eglinton Valley, Fiordland. Sixty-two stoats were caught in the 50 ha trapped area during summer 1990/91. The fledging of many first clutches, and the laying of second clutches, coincided closely with the period when high numbers of stoats were being caught in traps. Eighty percent of the nests in the trapped area fledged young, compared with only 36% in the untrapped area. Pairs produced nearly twice as many young in the trapped area. A higher proportion of breeding females disappeared from the untrapped area. In the two subsequent summers, 29 and 14 stoats were caught, and breeding success was higher Received 29 August 1995; accepted 30 April 1996 than previously recorded in both trapped and untrapped areas. We suggest that trapping in the year following a stoat irruption may also be warranted.

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Section: Assessing the Effectiveness Of Trappingmentioning

confidence: 99%

Control of a stoat (Mustela erminea) population irruption to enhance mohua (yellowhead) (Mohoua ochrocephala) breeding success in New Zealand

O’Donnell¹,

Dilks²,

Elliott

1996

New Zealand Journal of Zoology

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“…In species with complex group dynamics and cooperative breeding strategies, including the whitehead (McLean and Gill, 1988;Gill and McLean, 1992), consistent variation in plumage brightness may communicate rank-order signals important for familiarity and individual recognition (Irwin and Price, 1999;Tibbetts and Dale, 2007). Perceivable differences in white coloration may also signal to conspecifics or mates male phenotypic quality in itself through better male condition during molt (McGraw et al, 2002) or reflect ectoparasitic loads known to affect plumage brightness (Gill and Veitch, 1990;Hunt et al, 1998;Johnsen et al, 2003;Hegyi et al, 2007).…”

Section: Discussionmentioning

confidence: 95%

“…For instance, several behavioral adaptations may reduce nest predation in the whitehead, including cryptic nest site use and sole female incubation (McLean, 1987;McLean and Gill, 1988). These, in conjunction with the duller and perhaps less conspicuous female plumage of whitehead, may be beneficial to reduce nest predation (Martin andBadyaev, 1996, Hofmann et al, 2008) and/or obligate brood parasitism by long-tailed cuckoos Urodynamis taitiensis specializing on whiteheads (Falla et al, 1975;Anderson et al, 2009).…”

Section: Discussionmentioning

confidence: 95%

“…Recent conservation management of this species has focused on translocations of whiteheads to predator-free islands and mainland sites under conservation management and have included Tiritiri Matangi Island, Tawharanui Regional Park, and the Waitakere Ranges near Auckland City. The whitehead is a group-living cooperative breeder with helpers at the nest usually recruited from among the male progeny of previous breeding seasons (Falla et al, 1975;Soper, 1984;McLean and Gill, 1988;Gill and McLean, 1992). Males are consistently larger in several plumage and mensural traits (Gill and McLean, 1986) and also sexually dichromatic to the human visual system.…”

Section: Introductionmentioning

confidence: 97%

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Size dimorphism and avian‐perceived sexual dichromatism in a New Zealand endemic bird, the whitehead Mohoua albicilla

Igic¹,

Leuschner²,

Parker³

et al. 2010

Journal of Morphology

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Sex differences in behavior, morphology, and physiology are common in animals. In many bird species, differences in the feather colors of the sexes are apparent when judged by human observers and using physical measures of plumage reflectance, cryptic (to human) plumage dichromatism has also been detected in several additional avian lineages. However, it remains to be confirmed in almost all species whether sexual dichromatism is perceivable by individuals of the studied species. This latter step is essential because it allows the evaluation of alternative hypotheses regarding the signaling and communication functions of plumage variation. We applied perceptual modeling of the avian visual system for the first time to an endemic New Zealand bird to provide evidence of subtle but consistent sexual dichromatism in the whitehead, Mohoua albicilla. Molecular sexing techniques were also used in this species to confirm the extent of the sexual size dimorphism in plumage and body mass. Despite the small sample sizes, we now validate previous reports based on human perception that in male whiteheads head and chest feathers are physically brighter than in females. We further suggest that the extent of sexual plumage dichromatism is pronounced and can be perceived by these birds. In contrast, although sexual dimorphism was also detectable in the mass among the DNA-sexed individuals, it was found to be less extensive than previously thought. Sexual size dimorphism and intraspecifically perceivable plumage dichromatism represent reliable traits that differ between female and male whiteheads. These traits, in turn, may contribute to honest communication displays within the complex social recognition systems of communally breeding whitehead and other group-breeding taxa.

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“…Whiteheads are also co-operative breeders, with many breeding groups consisting of more than just a pair (McLean and Gill 1988). The role of secondary birds in whitehead groups (terminology after Dow 1980) varies; some help, some are just associated with the group and some breed but do not hold their own territories (McLean et al 1986, McLean andGill 1988).…”

Section: Introductionmentioning

confidence: 99%

The Breeding Biology and Habitat Relationships of the Yellowhead

Elliott¹

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<p>This study aimed to find an explanation for the decline of yellowheads and formulate recommendations for management and further research on the species. There were three main lines of investigation: basic population ecology and behaviour; the effect of introduced predators on breeding; and the habitat relationships of the species. A detailed study of a yellowhead population in the Eglinton Valley in Fiordland National Park was undertaken. Birds were caught and banded and their behaviour, breeding and survival monitored for 4 years. The relationship between yellowhead distribution and vegetation, topography, and fertility were investigated in part of Mt Aspiring National Park during one summer. Yellowheads suffered high rates of predation from stoats during "plagues" that occurred after heavy beech seeding. Three aspects of yellowhead biology made them vulnerable to mammalian predation: (1) they nested in holes and predators killed not only eggs and nestlings, but also incubating adults; (2) only the females incubated, thus losses to predators had a greater effect on the population than if equal numbers of males and females were killed; and (3) yellowheads nested later than most other forest passerines and were still nesting when stoat numbers reached their summer peak. Though the yellowhead's hole nesting habit made them vulnerable to mammals it restricted nest parasitism and predation by long-tailed cuckoos and hole nesting is likely to have evolved in response to cuckoos. Yellowheads were found to be tall forest specialists; they occurred more frequently in tall forests than short ones, and preferentially used the largest trees. Their choice of nest sites had no effect on their preference for any forest types. The forests they favoured grew mainly on fertile valley floors at low altitudes. Yellowhead populations in "good habitats" raised two broods a year and these populations are probably sufficiently productive to withstand stoat plagues occurring once every 5 years, the average frequency of this event. Populations in "poor habitats" raise only one brood and their productivity is probably insufficient to match losses to stoats. Such populations are probably slowly declining, and are very vulnerable to extinction. A habitat suitability index was devised and forests in the north of the South Island from which yellowheads have disappeared, were compared with those in the south where yellowheads persist. Northern forests were as good for yellowheads as southern ones. Thus, the combination of habitat preference and predation cannot account for the recent disappearance of yellowheads from the northern half of the South Island. The decline in yellowheads was attributed to both predation by introduced mammals and competition with introduced vespulid wasps. Predation may have eliminated yellowheads from podocarp-dominated forests where predator numbers are constantly high, but they survive in some beech forests where predator numbers rise only once every five years. However, even within beech forests only the most productive populations are sufficiently productive to survive predation and these populations are probably susceptible to competition with wasps which eat large numbers of invertebrates. Yellowheads are likely to be more vulnerable to wasp competition than other forest insectivores because: (1) predation has reduced their productivity more than other birds because they nest in holes; (2) they are specialised in low altitude, tall forest that the wasps also favour; (3) their breeding is later than most other forest birds and their period of juvenile dependence much longer. Yellowheads are still feeding fledgling yellowheads at the time when wasps numbers reach their peak in the autumn, whereas the offspring of other forest birds are independent by this stage.</p>

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Breeding of an Island-endemic Bird: the New Zealand Whitehead Mohorn albicilla; Pachycephalinae

Cited by 8 publications

References 7 publications

Control of a stoat (Mustela erminea) population irruption to enhance mohua (yellowhead) (Mohoua ochrocephala) breeding success in New Zealand

Control of a stoat (Mustela erminea) population irruption to enhance mohua (yellowhead) (Mohoua ochrocephala) breeding success in New Zealand

Size dimorphism and avian‐perceived sexual dichromatism in a New Zealand endemic bird, the whitehead Mohoua albicilla

The Breeding Biology and Habitat Relationships of the Yellowhead

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