We developed a set of microsatellite markers for the fan-tailed gerygone (Gerygone flavolateralis... more We developed a set of microsatellite markers for the fan-tailed gerygone (Gerygone flavolateralis), host of a brood parasite, the shining bronze-cuckoo (Chalcites lucidus). We used 454 pyro-sequencing to establish 17 polymorphic microsatellite markers. The number of alleles per locus ranged from 6 to 18, the expected heterozygosity from 0.328 to 0.931 and the polymorphism information content from 0.306 to 0.916. The developed set of microsatellites will allow us to determine the gerygone's mating system, which is crucial to understand inheritance of dichromatism in skin colour of their chicks.
Decades of research have shown that the coevolutionary arms race between avian brood parasites an... more Decades of research have shown that the coevolutionary arms race between avian brood parasites and their hosts can promote phenotypic diversification in hosts and brood parasites. However, relatively little is known about the role of brood parasitism in promoting phenotypic diversification of nestlings. We review field data collected over four decades in Australia, New Caledonia and New Zealand to assess potential for coevolutionary interactions between the shining bronze‐cuckoo (Chalcites lucidus) and its hosts, and how diversification at the nestling stage may be generating different subspecies. The shining bronze‐cuckoo is a specialist parasite of a few hosts in the family Acanthizidae. It has diversified into subspecies, of which the nestlings closely mimic the respective host nestlings in each region. Additionally, some cuckoo subspecies have polymorphic nestlings. The Acanthizidae hosts have similar breeding and nesting habits and only moderately effective frontline defences against parasitism at cuckoo egg laying or at the egg stages. However, some hosts have developed highly effective defences at the nestling stage by recognising and ejecting cuckoo nestlings from the nest. As with the cuckoo nestlings, some hosts have polymorphic nestlings. The coevolutionary interactions in each region suggest different evolutionary stages of the arms race in which either the parasite or the host is currently in the lead. The presence of moderately effective defences at the egg laying and egg stages might explain why some hosts do not have defences at the nestling stage. The south‐Pacific cuckoo – host systems are excellent models to explore the evolutionary mechanisms driving the diversification at the nestling stage in the coevolutionary arms race between avian brood parasites and their hosts.
The observation of rare behaviours can provide unexpected insights into the biology of a species.... more The observation of rare behaviours can provide unexpected insights into the biology of a species. Here, we report new observations of unusual or rare behaviours by the Kagu Rhynochetos jubatus of New Caledonia, a flightless bird already known for many curious traits. We observed the broken‐wing display, adoption of a chick by a neighbouring family and flexibility in the selection of cooperative breeding partners in response to disruption in their social organisation. Although infrequent, these observations demonstrate the highly developed social flexibility that enables Kagu to counter heavy population losses caused by predation. We think that rare behaviours could often be overlooked in species because restricted research objectives might not allow their discovery.
Abstract The Crow Honeyeater (Gymnomyza aubryana) is a critically endangered bird, endemic to the... more Abstract The Crow Honeyeater (Gymnomyza aubryana) is a critically endangered bird, endemic to the main island of New Caledonia, but it is poorly known owing to its elusive nature. We conducted playback surveys to assess the distribution, habitat preferences and vocal activity of the species. Crow Honeyeaters responded well to playback, with response rates reaching 67% at times. Our surveys revealed two distinct populations, separated by ∼250 km: one in the north of the island and the other, larger population in the south. The range of the northern population appears to be very small. Presence of the species was linked to rainforests growing on oligotrophic soils, primarily on ultramafic substrates. Approximately 315–700 km2 of suitable habitat for the species remains, corresponding to a maximum estimated population of 315–700 breeding pairs. The size and range of the Crow Honeyeater population is much smaller than previously assumed, and comprehensive management will be required to ensure its survival.
Advances in visual perceptual tasks have been mainly driven by the amount, and types, of annotati... more Advances in visual perceptual tasks have been mainly driven by the amount, and types, of annotations of large-scale datasets. Researchers have focused on fully-supervised settings to train models using offline epoch-based schemes. Despite the evident advancements, limitations and cost of manually annotated datasets have hindered further development for event perceptual tasks, such as detection and localization of objects and events in videos. The problem is more apparent in zoological applications due to the scarcity of annotations and length of videos-most videos are at most ten minutes long. Inspired by cognitive theories, we present a self-supervised perceptual prediction framework to tackle the problem of temporal event segmentation by building a stable representation of event-related objects. The approach is simple but effective. We rely on LSTM predictions of high-level features computed by a standard deep learning backbone. For spatial segmentation, the stable representation ...
The little fire ant, Wasmannia auropunctata, is an invasive species known to negatively affect ma... more The little fire ant, Wasmannia auropunctata, is an invasive species known to negatively affect many native species in its introduced range. Here, we studied the effect of little fire ant presence on the biomass of soil fauna in rainforest of New Caledonia to assess if little fire ants have an impact on an endangered endemic flightless bird, the kagu, Rhynochetos jubatus. The average biomass of soil fauna (except for millipedes) was lower in 53 sample plots with little fire ants than in 597 sample plots without little fire ants and the biomass decreased with increasing density of little fire ant nests. Millipedes on the contrary seemed to be positively impacted as their average biomass was higher in areas with fire ants than in areas without, but even millipede biomass decreased with increasing nest density of fire ants. Kagu density decreased with increasing area of rainforest invaded by little fire ants, suggesting, given their observed negative impact on soil fauna biomass, that t...
We deployed two GPS collars and one innovative harness-mounted GPS backpack with Iridium or Globa... more We deployed two GPS collars and one innovative harness-mounted GPS backpack with Iridium or Globalstar satellite data transmission on feral pigs in mountain rainforest with deep valleys in New Caledonia during the hot wet season. Both collar and backpack with Iridium transmission achieved high success rates of locations and the rate increased with decreasing interval length between locations. The collar with Globalstar transmission had very low fix rates at 13-h intervals and was insufficient to produce robust results. The backpack harness was still functional after 20 months of use and proved to be a reliable alternative to collars.
We developed a set of microsatellite markers for the fan-tailed gerygone (Gerygone flavolateralis... more We developed a set of microsatellite markers for the fan-tailed gerygone (Gerygone flavolateralis), host of a brood parasite, the shining bronze-cuckoo (Chalcites lucidus). We used 454 pyro-sequencing to establish 17 polymorphic microsatellite markers. The number of alleles per locus ranged from 6 to 18, the expected heterozygosity from 0.328 to 0.931 and the polymorphism information content from 0.306 to 0.916. The developed set of microsatellites will allow us to determine the gerygone's mating system, which is crucial to understand inheritance of dichromatism in skin colour of their chicks.
Decades of research have shown that the coevolutionary arms race between avian brood parasites an... more Decades of research have shown that the coevolutionary arms race between avian brood parasites and their hosts can promote phenotypic diversification in hosts and brood parasites. However, relatively little is known about the role of brood parasitism in promoting phenotypic diversification of nestlings. We review field data collected over four decades in Australia, New Caledonia and New Zealand to assess potential for coevolutionary interactions between the shining bronze‐cuckoo (Chalcites lucidus) and its hosts, and how diversification at the nestling stage may be generating different subspecies. The shining bronze‐cuckoo is a specialist parasite of a few hosts in the family Acanthizidae. It has diversified into subspecies, of which the nestlings closely mimic the respective host nestlings in each region. Additionally, some cuckoo subspecies have polymorphic nestlings. The Acanthizidae hosts have similar breeding and nesting habits and only moderately effective frontline defences against parasitism at cuckoo egg laying or at the egg stages. However, some hosts have developed highly effective defences at the nestling stage by recognising and ejecting cuckoo nestlings from the nest. As with the cuckoo nestlings, some hosts have polymorphic nestlings. The coevolutionary interactions in each region suggest different evolutionary stages of the arms race in which either the parasite or the host is currently in the lead. The presence of moderately effective defences at the egg laying and egg stages might explain why some hosts do not have defences at the nestling stage. The south‐Pacific cuckoo – host systems are excellent models to explore the evolutionary mechanisms driving the diversification at the nestling stage in the coevolutionary arms race between avian brood parasites and their hosts.
The observation of rare behaviours can provide unexpected insights into the biology of a species.... more The observation of rare behaviours can provide unexpected insights into the biology of a species. Here, we report new observations of unusual or rare behaviours by the Kagu Rhynochetos jubatus of New Caledonia, a flightless bird already known for many curious traits. We observed the broken‐wing display, adoption of a chick by a neighbouring family and flexibility in the selection of cooperative breeding partners in response to disruption in their social organisation. Although infrequent, these observations demonstrate the highly developed social flexibility that enables Kagu to counter heavy population losses caused by predation. We think that rare behaviours could often be overlooked in species because restricted research objectives might not allow their discovery.
Abstract The Crow Honeyeater (Gymnomyza aubryana) is a critically endangered bird, endemic to the... more Abstract The Crow Honeyeater (Gymnomyza aubryana) is a critically endangered bird, endemic to the main island of New Caledonia, but it is poorly known owing to its elusive nature. We conducted playback surveys to assess the distribution, habitat preferences and vocal activity of the species. Crow Honeyeaters responded well to playback, with response rates reaching 67% at times. Our surveys revealed two distinct populations, separated by ∼250 km: one in the north of the island and the other, larger population in the south. The range of the northern population appears to be very small. Presence of the species was linked to rainforests growing on oligotrophic soils, primarily on ultramafic substrates. Approximately 315–700 km2 of suitable habitat for the species remains, corresponding to a maximum estimated population of 315–700 breeding pairs. The size and range of the Crow Honeyeater population is much smaller than previously assumed, and comprehensive management will be required to ensure its survival.
Advances in visual perceptual tasks have been mainly driven by the amount, and types, of annotati... more Advances in visual perceptual tasks have been mainly driven by the amount, and types, of annotations of large-scale datasets. Researchers have focused on fully-supervised settings to train models using offline epoch-based schemes. Despite the evident advancements, limitations and cost of manually annotated datasets have hindered further development for event perceptual tasks, such as detection and localization of objects and events in videos. The problem is more apparent in zoological applications due to the scarcity of annotations and length of videos-most videos are at most ten minutes long. Inspired by cognitive theories, we present a self-supervised perceptual prediction framework to tackle the problem of temporal event segmentation by building a stable representation of event-related objects. The approach is simple but effective. We rely on LSTM predictions of high-level features computed by a standard deep learning backbone. For spatial segmentation, the stable representation ...
The little fire ant, Wasmannia auropunctata, is an invasive species known to negatively affect ma... more The little fire ant, Wasmannia auropunctata, is an invasive species known to negatively affect many native species in its introduced range. Here, we studied the effect of little fire ant presence on the biomass of soil fauna in rainforest of New Caledonia to assess if little fire ants have an impact on an endangered endemic flightless bird, the kagu, Rhynochetos jubatus. The average biomass of soil fauna (except for millipedes) was lower in 53 sample plots with little fire ants than in 597 sample plots without little fire ants and the biomass decreased with increasing density of little fire ant nests. Millipedes on the contrary seemed to be positively impacted as their average biomass was higher in areas with fire ants than in areas without, but even millipede biomass decreased with increasing nest density of fire ants. Kagu density decreased with increasing area of rainforest invaded by little fire ants, suggesting, given their observed negative impact on soil fauna biomass, that t...
We deployed two GPS collars and one innovative harness-mounted GPS backpack with Iridium or Globa... more We deployed two GPS collars and one innovative harness-mounted GPS backpack with Iridium or Globalstar satellite data transmission on feral pigs in mountain rainforest with deep valleys in New Caledonia during the hot wet season. Both collar and backpack with Iridium transmission achieved high success rates of locations and the rate increased with decreasing interval length between locations. The collar with Globalstar transmission had very low fix rates at 13-h intervals and was insufficient to produce robust results. The backpack harness was still functional after 20 months of use and proved to be a reliable alternative to collars.
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Papers by Jörn Theuerkauf