John K. Perrott

Mortality and behaviour of hihi, an endangered New Zealand honeyeater, in the establishment phase following translocation

We analysed mortality and behaviour of hihi, an endangered New Zealand honeyeater, in the first three months after translocation to 135 ha Mokoia island. Our aims were to assess: (1) whether mortality and behaviour were affected by the translocation process or post-release management, and (2) whether the fate of birds during this establishment phase affected the viability of the population. Forty hihi were translocated from the wild population on Little Barrier Island, released immediately in three different locations, and provided with sugar water feeders. Many of the birds suffered leg injuries due to the bands initially used, and up to 7 birds may have died from these injuries. Nevertheless, the mortality rate over the first three months was similar to the average rate over the first 3 years. Therefore, except for the bands used, there was no evidence of post-release mortality associated with translocation stress. Most hihi discovered the feeders quickly. However, feeder use varied greatly among birds and there was no evidence that access to feeders reduced mortality. Access to feeders also did not affect overall time spent foraging. However, birds using feeders allocated most of their foraging effort to invertebrate feeding, whereas birds not using feeders foraged mostly on flowers and fruits. Hihi dispersed quickly after release, and moved all over the island. Transmitters increased re-sighting rates over the first 3 weeks, but intensive observation during that period provided no useful information relevant to subsequent survival and reproduction. There was a slight tendency for birds to settle closer to their release sites than expected by chance, but there was no tendency for birds released together to form breeding pairs. We conclude that the viability of this population was not affected by any problems in the establishment phase. However, the population has had a consistently high mortality rate over the first 3 years, and its long-term viability appears poor. Our subsequent research is, therefore, addressing the factors that might be limiting the population in the long-term.

Aspergillus fumigatus Densities in Relation to Forest Succession and Edge Effects: Implications for Wildlife Health in Modified Environments

The hihi (or stitchbird, Notiomystis cincta) is a New Zealand endemic nectivorous forest bird now restricted to one pristine island. Relocation to establish viable hihi populations on other islands has been the main conservation action since the early 1980s. To date, hihi reintroductions to young growth islands have had poor success despite the absence of mammalian predators. It was thought that past failures were due to food limitation, but research suggests that food limitation alone cannot account for their poor survivorship. Post-mortems of dead hihi has shown that aspergillosis caused by Aspergillus fumigatus is a major mortality factor and there is current concern regarding their susceptibility to this fungal disease. In this paper we develop and assess the hypothesis that A. fumigatus limits hihi population viability on modified islands, and suggest that A. fumigatus is a potential indicator species for habitat disturbance. We report that the prevalence of A. fumigatus spores in the soil is much higher in young growth forests and forest edge habitats. Results suggest that hihi mortality rates between islands are potentially due to differential exposure to A. fumigatus spores. We assess relationships between habitat disturbance, A. fumigatus contamination and hihi mortality rates by testing the following predictions: (1) that densities of A. fumigatus spores will be higher on modified islands, (2) that densities of A. fumigatus spores on islands will be correlated with hihi mortality rates and (3) that densities of A. fumigatus spores will be higher at the forest edge than in the interior. We test each of these predictions using soil samples, air samples and samples of nectar from plant species fed on by hihi.

Isolation and Identification of Aspergillus spp. from Brown Kiwi (Apteryx mantelli) Nocturnal Houses in New Zealand

SUMMARY Aspergillosis, a disease caused by infection with Aspergillus spp., is a common cause of death in birds globally and is an irregular cause of mortality of captive kiwi (Apteryx spp.). Aspergillus spp. are often present in rotting plant material, including the litter and nesting material used for kiwi in captivity. The aim of this study was to survey nocturnal kiwi houses in New Zealand to assess the levels of Aspergillus currently present in leaf litter. Samples were received from 11 nocturnal kiwi houses from throughout New Zealand, with one site supplying multiple samples over time. Aspergillus was isolated and quantified by colony counts from litter samples using selective media and incubation temperatures. Isolates were identified to the species level by amplification and sequencing of ITS regions of the ribosomal. Aspergillus spp. were recovered from almost every sample; however, the levels in most kiwi houses were below 1000 colony-forming units (CFU)/g of wet material. The predominant species was Aspergillus fumigatus, with rare occurrences of Aspergillus niger, Aspergillus nidulans, and Aspergillus parasiticus. Only one site had no detectable Aspergillus. The limit of detection was around 50 CFU/g wet material. One site was repeatedly sampled as it had a high loading of A. fumigatus at the start of the survey and had two recent clinical cases of aspergillosis diagnosed in resident kiwi. Environmental loading at this site with Aspergillus spp. reduced but was not eliminated despite changes of the litter. The key finding of our study is that the background levels of Aspergillus spores in kiwi nocturnal houses in New Zealand are low, but occasional exceptions occur and are associated with the onset of aspergillosis in otherwise healthy birds. The predominant Aspergillus species present in the leaf litter was A. fumigatus, but other species were also present. Further research is needed to confirm the optimal management of leaf litter to minimize Aspergillus spore counts. However, in the interim, our recommendations are that leaf litter should be freshly collected from areas of undisturbed forest areas and spread immediately after collection, without interim storage. RESUMEN Aislamiento e identificación de Aspergillus spp. de alojamientos nocturnos de kiwi marrón (Apteryx mantelli) en Nueva Zelanda. La aspergilosis, enfermedad causada por la infección con Aspergillus spp., es una causa común de muerte en las aves a nivel mundial y es una causa no regular de mortalidad de kiwis en cautiverio (Apterix spp.). El Aspergillus spp. está a menudo presente en la descomposición de la material vegetal , incluyendo la cama y el material utilizado para la anidación del kiwi en cautiverio. El objetivo de este estudio fue examinar los alojamientos nocturnos de kiwis en Nueva Zelanda para evaluar los niveles de Aspergillus actualmente presentes en la cama de hojas. Se recibieron muestras de 11 alojamientos nocturnos de kiwi de toda Nueva Zelanda, con un sitio que suministró múltiples muestras con el tiempo. Se aisló y se cuantificó Aspergillus por recuento de colonias de las muestras de cama usando medios selectivos y temperaturas de incubación. Los aislamientos fueron identificados a nivel de especie mediante amplificación y secuenciación de regiones ribosomales ITS. Se recuperó Aspergillus spp. de casi todas las muestras, sin embargo, los niveles en la mayoría de los alojamientos de kiwi estaban por debajo de las 1000 unidades formadoras de colonias (UFC )/g de materia húmeda. La especie predominante fue Aspergillus fumigatus, con presentaciones poco frecuentes de Aspergillus niger, Aspergillus nidulans y Aspergillus parasiticus. Sólo un sitio no mostró Aspergillus detectable. El límite de detección fue de alrededor de 50 UFC/g de materia húmeda. Un sitio fue muestreado varias veces ya que tenía una alta carga de A. fumigatus al inicio del muestreo y estaba relacionado con dos casos clínicos recientes de aspergilosis diagnosticados en los kiwis residentes. La carga ambiental en este sitio con Aspergillus spp. se redujo pero no fue eliminada totalmente a pesar de los cambios de la cama. El hallazgo clave de este estudio clave es que los niveles basales de esporas de Aspergillus en los alojamientos nocturnos de kiwis en Nueva Zelanda son bajos, pero se presentan excepciones ocasionales que están asociadas con la aparición de aspergilosis en aves sanas. La especie predominante de Aspergillus presente en la cama de hojas fue A. fumigatus, pero otras especies también estuvieron presentes. Se necesita investigación adicional para confirmar el tratamiento óptimo de la cama de hojas para minimizar los conteos de esporas de Aspergillus. Sin embargo, mientras tanto, la recomendación es que la cama de hojas debe recolectarse fresca de áreas forestales no contaminadas y debe extenderse inmediatamente después de la recolección, sin almacenamiento temporal.