
Jörn TheuerkaufMuseum and Institute of Zoology, Polish Academy of Sciences
Jörn Theuerkauf
Prof. dr hab.
About
126
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Introduction
Jörn Theuerkauf works at the Museum and Institute of Zoology, Polish Academy of Sciences. Jörn does research in behavioural and evolutionary ecology on birds and mammals in Europe and the Pacific.
Additional affiliations
March 2014 - October 2019
October 1996 - May 2003
Publications
Publications (126)
Caledargiolestes janiceae Lieftinck, 1975 was erected on the basis of a single not-fully mature male. Eleven years later a female was captured but never described. Despite further searching, this species was only rediscovered in early 2022 with one female and two males (immature and mature) collected. This paper provides descriptions of the female...
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...
Species on islands that evolved without mammalian predators are commonly considered naïve to these introduced animals and therefore potentially vulnerable to predation. The endemic kagu Rhynochetos jubatus, a flightless bird, is the most emblematic species of New Caledonia. As the natural top predator of the ground fauna in rainforest, it is an exc...
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 deca...
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...
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 ka...
In ecological studies sampling must be stratified to ensure a sample population that best represents the entire population studied.
Meta-analyses assessing global patterns should also use a stratified data structure to ensure unbiased results.
We show that this is generally not the case, as individual studies are heavily biased toward the Norther...
Using offline training schemes, researchers have tackled the event segmentation problem by providing full or weak-supervision through manually annotated labels or self-supervised epoch-based training. Most works consider videos that are at most 10’s of minutes long. We present a self-supervised perceptual prediction framework capable of temporal ev...
[This corrects the article DOI: 10.1093/cz/zoab066.].
Odonata fauna of the islands of Wallis and Futuna has been investigated during a two week field trip in 2020 and occasional observations in 20072012. Updated species checklist and faunistic information following nomenclature changes, new taxonomic information and distribution data are proposed. Presently, 15 species are known from Wallis & Futuna....
Nestling ejection is a rare type of host defence against brood parasitism compared to egg ejection. Theoretically, host defences at both egg and nestling stages could be based on similar underlying discrimination mechanisms but, due to the rarity of nestling ejector hosts, few studies have actually tested this hypothesis. We investigated egg and ne...
Nestling ejection is a rare type of host defence against brood parasitism compared to egg ejection. Theoretically, host defences at both egg and nestling stages could be based on similar underlying discrimination mechanisms but, due to the rarity of nestling ejector hosts, few studies have actually tested this hypothesis. We investigated egg and ne...
We investigated winter selection of resting sites by wolves in a commercial pine forest to test if roads, settlements , and type of forest influenced the resting behaviour of wolves during the day and at night. At the landscape scale, wolves selected resting sites that were farther from settlements, public roads and high-traffic forest roads than r...
Nest predation and avian brood parasitism are the main sources of nest failure in many passerine birds. Large predators threaten both brood and parents, whereas brood parasites pose only a danger to eggs or nestlings. The fan-tailed gerygone Gerygone flavolateralis from New Caledonia is subjected to high rates of nest predation by the New Caledonia...
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...
Available information on Gynacantha Rambur, 1842 species from the South Pacific is reviewed. Specimens were found to be sufficiently similar to G. rosenbergi Kaup in Brauer, 1867 to be placed in the same species group (G. rosenbergi group—established here) but also distinct enough to form a subgroup of its own (G. rosenbergi Pacific group). All spe...
The wolf Canis lupus population occupying the lowlands of central Europe is divided into two management units: the Baltic population east of the Vistula river and the Central European population to the west. We re-evaluated arguments for this division in the context of the ongoing wolf recovery and its usefulness for wolf management in Poland. To d...
Temporal event segmentation of a long video into coherent events requires a high level understanding of activities' temporal features. The event segmentation problem has been tackled by researchers in an offline training scheme, either by providing full, or weak, supervision through manually annotated labels or by self-supervised epoch based traini...
Predation and brood parasitism are common reasons for nesting failure in passerine species and the additive impact by invasive species is a major conservation concern, particularly on tropical islands. Recognising the relative contribution of the different components of nesting failure rates is important to understand co‐evolutionary interactions w...
We investigated by snow tracking and GPS telemetry how wolves Canis lupus used a dense (4 km/km2) network of forest roads for travel and scent marking. Forty-six percent of wolf trails but only 4.6% of telemetry locations were on forest roads. Wolves used forest roads to travel fast and far across their home ranges but spent relatively little time...
Previous research reported a unique haematological profile in the flightless Kagu (Rhynochetos jubatus). To verify this, we analysed blood of eight wild and four captive Kagu. The haematological profiles of our captive birds resembled those of the previously studied captive Kagu. Haemoglobin concentration, mean corpuscular haemoglobin concentration...
Compared to other archipelagos of the Pacific, the New Caledonian Odonata fauna is rich and diverse with 56 valid species or subspecies (23 endemics, 41%) from eight families (four Zygoptera: Argiolestidae, Coenagrionidae, Isostictidae, Lestidae, and four Anisoptera: Aeshnidae, Corduliidae, Synthemistidae, Libellulidae) and 31 genera (including fou...
Compared to other archipelagos of the Pacific, the New Caledonian Odonata fauna is rich and diverse with 56 valid species or subspecies (23 endemics, 41%) from eight families (four Zygoptera: Argiolestidae, Coenagrionidae, Isostictidae, Lestidae, and four Anisoptera: Aeshnidae, Corduliidae, Synthemistidae, Libellulidae) and 31 genera (including fou...
Apart from a few well-studied examples, there is little information regarding the life history and ecological requirements of brood parasites and their hosts in most cuckoo–host systems, particularly in tropical areas. In New Caledonia, the Fan-tailed Gerygone Gerygone flavolateralis, is the exclusive host of the Shining Bronze-cuckoo, Chalcites lu...
Mimicry by avian brood parasites favours uniformity over variation within a breeding attempt as host defence against parasitism. In a cuckoo-host system from New Caledonia, the arms race resulted in both host (Gerygone flavolateralis) and parasite (Chalcites lucidus) having nestlings of two discrete skin colour phenotypes, bright and dark. In our s...
Background: Parasites can exert selection pressure on their hosts through effects on survival, on reproductive
success, on sexually selected ornament, with important ecological and evolutionary consequences, such as changes
in population viability. Consequently, hemoparasites have become the focus of recent avian studies. Infection varies
significa...
Polyandry has been studied in many species, especially birds [1]. Exclusively fraternal polyandry (several full or half-brothers with one unrelated female) is only known in human societies [2, 3], in which it is an important mechanism for limiting reproductive output [3] in association with scarce environmental resources [2]. However, the social or...
Extra-pair copulation can increase genetic diversity and offspring fitness. However, it may also increase intra-nest variability in avian hosts of brood parasites, which can decrease the discrimination ability of host parents towards the parasite. In New Caledonia, the Fan-tailed Gerygone (Gerygone flavolateralis), which is parasitized by the Shini...
Information on 141 samples of 127 Fan-tailed Gerygones (29 breeding pairs and their 69 offspring, 36 breeding attempts) in New Caledonia.
ID: ID of individual, nest: nest number, breeding attempt: number of breeding attempt, status: parent or nestling, sex: F = female, M = male, habitat: type of habitat surrounding the nest, brood polymorphism: 0 =...
Rhynochetos orarius has been described from Holocene fossils as the sister species of the smaller extant Kagu Rhynochetos jubatus, a bird endemic to New Caledonia. However, we argue that there has never been evidence justifying the description of R. orarius. Additionally, for biogeographical reasons it seems unlikely that two Kagu species would hav...
Australia, New Zealand, New Guinea, Wallacea, and the islands of the Pacific Ocean collectively possess 42% of the world’s parrot species, including half of all Critically Endangered species. We used comparative methods to review the factors related to extinction risk of 167 extant and 5 extinct parrot species from this region, subsequently referre...
Selection of kill sites is an important part of predation. In human-modified habitats, anthropogenic landscape features may increase or decrease hunting efficiency of predators. We investigated which habitat attributes increase predation success in wolf Canis lupus hunting for ungulates in an intensively managed forest of western Poland. We used GP...
Positive range–abundance relationships in Indo-Pacific bird communities A B S T R A C T Reeve et al. (2016, Ecography, 39, 990–997) recently reported negative range–abun-dance relationships in Indo-Pacific bird communities and speculated that geographical isolation facilitates the evolution of broad-niched, small-ranged and abundant species. We tes...
To assess the effects of naturally occurring heavy metals on wild birds, we compared reproductive success and heavy metal contents in feathers of Kagu Rhynochetos jubatus living on ultramafic (rich in heavy metals) soils with those of Kagu living on non-ultramafic soils. From 2003 to 2016, we monitored breeding of 19 Kagu families by radio-tracking...
Combining radio-telemetry with direct observations, we followed 22 released juvenile captive-bred capercaillies throughout the day to assess if their seasonal and daily patterns of activity, movements, and diet are in accordance with published information on wild birds. Day length was the most important factor determining birds' mobility and activi...
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 r...
Virulence of avian brood parasites can trigger a coevolutionary arms race, which favours rejection of parasitic eggs or chicks by host parents, and in turn leads to mimicry in parasite eggs or chicks [1-7]. The appearance of host offspring is critical to enable host parents to detect parasites. Thus, increasing accuracy of parasites’ mimicry can fa...
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....
Hemicyrthus blaffarti new species (Coleoptera: Scarabaeidae: Dynastinae) from the Parc Provincial de la Rivière Bleue in southern New Caledonia is described. It differs from the most similar species, H. elongatus, by the completely and sharply margined pronotal base, the presence of elytral micropunctures, shorter apical setae of the mesotibiae and...
A new mother-assisted rearing and release technique (" born to be free ") reduces the exploratory movements and increases survival of young capercaillies Abstract We compared the mobility and survival rates of two groups of young capercaillies that were reared and released by different methods. One group consisted of 21 radio-tracked chicks that we...
Invasive species usually go through a period of reduced genetic variability due to a bottleneck. The genetic constitution of an invading population should therefore reflect the time since invasion and the number of introduction events. We studied genetic population structure of three rat species occurring sympatrically on the island of Futuna (46 k...
We assessed heavy metal concentrations in feathers of 38 Kagus Rhynochetos jubatus living on ultramafic soils in New Caledonia. Concentrations of heavy metals in down feathers were similar to concentrations in shafts of primary or secondary feathers, whereas the concentrations in vanes were much higher, indicating that concentrations in down feathe...
The water requirements of birds in humid areas are not well understood. Even rainforests have dry seasons, during which birds might experience water short-ages. We surveyed use of puddles as a water source for birds in a New Caledonian rainforest during the dry season using camera traps. We found that birds frequently used puddles, and that especia...
We present a dichotomous key to identify adults of all presently described Odonata
of New Caledonia including the Loyalty Islands (Melanesia) and Wallis and Futuna
(Western Polynesia). The key covers a total of 58 species of which approximately 50 % are
regionally endemic, while others are more widespread species inhabiting neighboring archipelagos...
Beak and feather disease virus (BFDV) is a recognised key threat for the conservation of parrots globally, causing morbidity and mortality of individuals in susceptible species. We present findings from a survey in 2012 to investigate the presence of BFDV in wild New Caledonian parrots, including the endangered Ouvea Parakeet (Eunymphicus uvaeensis...
In Europe, brown bear Ursus arctos habitats frequently overlap with human settlements and infrastructure. We tested whether anthropogenic structures played an important role in habitat selection by brown bears in the Bieszczady Mountains, Poland. We analysed 668 signs of brown bear presence recorded during 6 counts along 246 km of transects (total...
Standardised surveys are essential for monitoring populations and identifying areas that are critical for conservation. With the aim of developing a standardised method of surveying parrots in the rainforests of New Caledonia, we used distance sampling to estimate densities of New Caledonian Parakeets (Cyanoramphus saisseti), Horned Parakeets (Euny...
Individual studies in wildlife science are indicative rather than conclusive. Although multiple studies can be meta-analyzed in such a way that scientific hypotheses can be tested, robust meta-analyses are often difficult or impossible if variables of interest are not measured in a uniform manner. We hypothesized that measurements, even of basic an...
Knowing the distribution and abundance of species is critical for conservation, yet field surveys are often limited in their spatial extent. In this study, we use ecological niche models to infer the current and future distribution of New Caledonian Parakeets (Cyanoramphus saisseti), Horned Parakeets (Eunymphicus cornutus), and Ouvea Parakeets (Eun...
We surveyed odonates at 46 sites in north-eastern New Caledonia,
including 38 primary sites in three catchments on
and around Mt. Panié. A total of 23 species were recorded
during this survey, which comprises 41% of the 56 species
known for the country. The lowest number of species was
documented within the La Guen river catchment, where
less speci...
We assessed the abundance of six invasive species (Ship rats Rattus rattus, Pacific rats R. exulans, rusa deer Rusa timorensis russa, feral pigs Sus scrofa f. domestica, feral cats Felis catus, and stray dogs Canis lupus familiaris) in the Mt. Panié mountains during a Rapid Biological Assessment in 2010, building on research conducted from 2004–200...
Numerous broken shells of a rare endemic snail Placostylus fibratus, a species rated as vulnerable, were scattered around rocky beds of dry creeks in rainforest of New Caledonian. We set a video camera near one site to identify the predator. We recorded a New Caledonian crow Corvus moneduloides dropping and consuming the snail. This is the first di...
Human disturbance is thought to be a major source of stress for animals but breeding status, social interactions and food availability are also potential sources. Long-lasting stress may adversely affect the fitness of animals and for that reason the evaluation of stressors is important for conservation of threatened species. The aim of our study w...
Based on 805 observations of 63 species, we identified the main breeding seasons of avian trophic guilds in New Caledonia. Most omnivorous and carnivorous birds had undefined breeding periods with moderate peaks during the warm/dry season and the hot/rainy season. In contrast, nectarivorous, frugivorous, granivorous and insectivorous species had ma...
Rats are major reservoirs of leptospirosis and considered as a main threat to biodiversity. A recent introduction of Rattus rattus to the island of Futuna (Western Polynesia) provided the opportunity to test if a possible change in species composition of rat populations would increase the risk of leptospirosis to humans. We trapped rodents on Walli...