Nestor Notabilis Research Articles

Assessing kea perception of cereal baits using modelling of spectral reflectance

Kea (Nestor notabilis) are highly inquisitive parrots endemic to Aotearoa/New Zealand that often interact with novel items in their environment. To help reduce the risk of by-kill of kea during aerial 1080 pest-control operations, we investigated how kea perceive the different types of cereal baits typically used in such pest control.

Conditioned aversion in kea to cereal bait: A captive study using anthraquinone

The kea (Nestor notabilis, plural kea), an alpine parrot endemic to New Zealand’s South Island, is endangered by introduced mammalian predators. Aerially deployed 1080 (sodium fluoroacetate) toxin in cereal baits is an important tool in the control of mammalian pest species in New Zealand. Kea are omnivorous and forage on the ground, and thus are at direct risk of consuming toxic baits. This study examined the degree to which kea can develop an aversion to bait that mimicked the visual, textural, and olfactory nature of 1080 baits in two standard cereal bait types, Wanganui #7 and RS5. Treatment baits contained 2.7 % by weight anthraquinone (CAS 84-65-1), a secondary bird repellent that causes an emetic response through mild gut irritation. A sample of 11 captive kea were hand-offered Wanganui #7 baits, starting with untreated bait to obtain a baseline measure of consumption. Two days later the birds were hand-offered treated (repellent) baits in two sessions over four days. In subsequent sessions untreated baits were again offered to measure aversion. Of the 10 birds that consumed untreated bait during the initial session, all 10 consumed at least some treated bait and only one consumed untreated bait in the final session. The process was repeated with RS5 bait. Of the 9 kea that ate the treated RS5 bait, 4 subsequently consumed untreated bait but only one to a level that would have been fatal (LD50) with toxic bait. These results show that kea can learn to become averse to baits mimicking those used in aerial 1080 operations, and that this aversion response lasts at least through 6 interactions with baits (3 per day). This opens up the possibility of creating a learned aversion in wild kea populations, and mitigating their risk from aerial 1080 operations.

Kea show three signatures of domain-general statistical inference

One key aspect of domain-general thought is the ability to integrate information across different cognitive domains. Here, we tested whether kea (Nestor notabilis) can use relative quantities when predicting sampling outcomes, and then integrate both physical information about the presence of a barrier, and social information about the biased sampling of an experimenter, into their predictions. Our results show that kea exhibit three signatures of statistical inference, and therefore can integrate knowledge across different cognitive domains to flexibly adjust their predictions of sampling events. This result provides evidence that true statistical inference is found outside of the great apes, and that aspects of domain-general thinking can convergently evolve in brains with a highly different structure from primates. This has important implications not only for our understanding of how intelligence evolves, but also for research focused on how to create artificial domain-general thought processes.

Vocal development in nestling kea parrots (Nestor notabilis)

ABSTRACT This study investigates vocal development of nestling kea parrots (Nestor notabilis). First, we examine how many structurally distinct call types were present during the nestling period, and the age in which call types occurred. Based on studies with other avian species, we predicted that kea nestlings would have multiple call types, with some present at hatching and others emerging later in the nestling period. Results showed that nestlings have four distinct call types, two present at hatching, and two emerging when the nestlings undergo large physical changes in the second week of life. While two of the call types developed gradually towards more adult-like structures, the other two did not and were apparently only used for communication in the nest. Second, we tested whether nestlings could be discriminated individually based on their calls. All four call types were individually discriminable from hatching until the end of the study, thus providing evidence for vocal signatures. While the function of vocal signatures cannot be ascertained from this study, kea breeding biology rules out explanations based on preventing misdirected parental care. We suggest that vocal signatures may be relevant to the division of parental resources in the nest.

Kea (Nestor notabilis) represent object trajectory and identity

The ability to represent both the identity and trajectory of hidden objects underlies our capacity to reason about causal mechanisms. However, to date no studies have shown that non-human animals are capable of representing these two factors simultaneously. Here, we tested whether kea can represent out-of-sight object trajectories and identities by presenting subjects with three tasks, each of which involved tracking or predicting hand trajectories as they moved behind a screen. Taken together, our results suggest that kea have the capacity for mental simulation in complex tasks involving moving hidden objects.

Prevalence and characterisation of wounds in sheep attributed to attacks by kea (Nestor notabilis) on high country farms in New Zealand

ABSTRACTAims: To characterise and classify wounds in sheep suspected to have been caused by attacks by kea (Nestor notabilis) (kea strike), and to report the prevalence of these wounds on five high country farms in the South Island of New Zealand.Methods: Data were collected from farms between 28 August 2012 and 20 September 2013. Sheep were examined opportunistically immediately after shearing for signs of wounds caused by kea. The age and sex of sheep were also recorded. Wounds were measured and characterised as recent, healing, or healed, and the estimated true prevalence was calculated for each farm.Results: Injuries consistent with kea strike wounds were identified in 70/13,978 (0.5%) sheep examined. The estimated true prevalence varied between farms, from 0 (95% CI = 0–0.16) to 1.25 (95% CI = 0.97–1.61)%. Of the 76 wounds identified, 61 (80%) were located in the lumbar region, and 74 (97%) consisted of full-thickness ulceration of the skin, one showed evidence of injury to muscle and one to bone. The median length of the 63 wounds measured was 6 (min 1, max 23.5) cm, and 10/63 (13%) were categorised as recently healed, 47/63 (62%) as healing, and 17/63 (22%) as recent wounds.Conclusions: The results of this study show that kea strike on sheep was occurring at a low prevalence on the high country farms surveyed. The wounds identified were survivable, but the welfare impact of kea strike on sheep should be considered in balance with the conservation status of kea. There was clear variation in the prevalence of wounds attributed to kea strike between the farms but we were not able to identify the risk factors contributing to these differences. Future studies of kea strike should examine variables such as altitude, local kea density and distribution, and differences in kea strike management and husbandry practices, and should include high country farms without a history of kea strike.

Are kea prosocial?

AbstractProsocial behaviour is widespread in humans, but evidence for its occurrence in other species is mixed. We presented a parrot species, the kea (Nestor notabilis) with a series of experiments to test whether they exhibit prosocial tendencies. Across the first round of testing, in our first condition, two of the four kea acted prosocially, as they preferred to choose a prosocial token which rewarded both themselves and a partner, rather than a token that rewarded only themselves. Three of the four kea then showed a preference for the prosocial token in a second condition where they alternated taking turns with a partner. However, no kea showed a decrease in the third yoked control condition in which the experimenter replicated the token choice made by the partner in the previous alternating trials. This yoked condition was used to dissociate truly reciprocal behaviour, whereby the actor made choices based on their partner's choices, from a response to the amount of rewards conferred to the partner. Finally, three of the four kea continued to choose the prosocial token in the fourth asocial control condition where no partner was present. However, in round two of testing, one kea changed its token choices to a similar pattern to that expected if kea are prosocial, in that it preferred the prosocial token in the initial condition, showed a trend for the prosocial token when turns were alternated, but chose at chance in the yoked and asocial conditions. This study therefore found no evidence of spontaneous reciprocity in kea but further testing is required before we can conclude that kea are not capable of prosocial behaviour at all.

Kea Nestor notabilis mothers produce nest‐specific calls with low amplitude and high entropy

Vocal behaviour of nesting altricial birds is subject to selection pressure from several sources. Offspring beg to attract parents’ attention, thus increasing the chances of being fed, but also increasing the chances of being detected by predators. Research on passerines has shown that parents may reduce the risk of nest predation by alarm calling to warn nestlings to be quiet, and by producing food calls which solicit begging when parents are present to defend the nestlings. Both nestlings and parents may reduce the risk of predator detection by producing calls of low amplitude and high entropy which are acoustically difficult to locate. Although extensive research has been undertaken on nesting passerine vocalizations, little is known about parrots in this regard, and studies are needed to determine whether parrots show similar adaptations. We investigated the calling behaviour of Kea Nestor notabilis mothers during the nesting period to determine whether maternal vocalizations were adapted in a way that could increase the chance of brood success. A microphone was installed inside the nest to record calls produced both inside the nest and in the direct vicinity. Our prediction was that calls outside the nest would be easy to locate and could function as alarm calls to alert conspecifics or distract the predator, whereas calls inside the nest would be difficult to locate and could serve to communicate with nestlings without alerting predators. Our results accorded with these predictions. Calls produced outside the nest were loud and tonal, and corresponded to previously described Kea alarm calls. Calls produced inside the nest, however, were high‐entropy and low‐amplitude calls, and formed a distinct structural category. We thus provide the first evidence that a parrot species has a vocal category for communication inside the nest, and that calls within this category are structured in a way that could reduce the risk of nest predation.

No evidence of mirror self-recognition in keas and Goffin’s cockatoos

Abstract So far only one bird species, a corvid, passed the mark test for mirror self-recognition (MSR) although the results have been questioned. We examined the capacity for MSR in another large-brained avian taxon, parrots, with keas (Nestor notabilis) and Goffin’s cockatoos (Cacatua goffini). After several weeks of mirror habituation, they were subjected to the mark test using different marks and mark placements while facing horizontal and vertical mirrors simultaneously. The keas had an additional control condition in which their reaction towards a marked or non-marked conspecific behind a transparent partition was compared to their own reflection. No evidence of MSR was found in either species. Keas responded to their reflection comparably to a conspecific behind a clear separation. Goffin’s cockatoos showed fewer social responses towards their horizontal reflection compared to their vertical reflection, suggesting that they may interpret them differently.

Testing the causal understanding of water displacement by kea (Nestor notabilis)

Abstract Rooks, Eurasian jays and NC crows have already solved the Aesop’s fable paradigm, using stones to raise a water level to get a previously out of reach reward. Here we test kea parrots on their understanding of water displacement. In Experiment 1, they preferentially chose the water-filled tube over two solid substrates (sand, rocks) within 5 trials. In Experiment 2, they generalised to novel coloured substrates in the first trial. In Experiment 3, confronted with two water-filled tubes, one of which was made unsolvable by preventing the water from rising, none of the kea managed to solve the task. This suggests that their performance in Experiments 1 and 2 was reward association with the liquid-filled tube, without attendance to changes in water level. These results therefore provide no evidence of causal understanding of water displacement and highlight that such an understanding is not required for solving Aesop’s Fable.

Vocal conditioning in kea parrots (Nestor notabilis).

In laboratory studies of vocal behavior in animals, subjects are normally isolated in a sound-insulated chamber for recording, but such socially isolated conditions may reduce the chances that they will vocalize. Indeed, past studies using such methods have faced the challenge that subjects remained silent. Knowledge of conditions under which subjects are more likely to vocalize could thus improve experimental design. This study investigated (a) whether kea (Nestor notabilis) could be trained to increase vocal production using operant conditioning and (b) the conditions under which such training was feasible. We found that visual contact with other kea increased the chances that a subject would vocalize spontaneously, therefore making training through positive reinforcement possible. In the conditions where kea could only hear but not see the rest of the group, they were much less likely to vocalize. Subjects were quickly trained to increase vocal production while in visual contact with other kea, and the training remained effective even when visual access later was removed. The procedure described here could be used as a first step in future laboratory studies of vocal behavior, carried out before subjects are isolated, to overcome the challenge of inducing isolated subjects to vocalize. (PsycINFO Database Record

Kea (Nestor notabilis) decide early when to wait in food exchange task.

The ability to forego an immediate reward in favor of a bigger or better one at a later point has been linked with advanced cognitive skills, such as impulse control and forward-planning, and can be assessed by the classic food exchange paradigm. While the ability to perform in such tasks has long been regarded as an exclusive trait of humans and some mammals, that is, primates and dogs, in recent years some bird species have been found to perform similarly as primates. Here we test 10 captive kea (Nestor notabilis), using a food exchange paradigm standardized in earlier experiments, but adding the use of a container to hold the initial item. The subjects reached waiting times of up to 160 s. They also showed significantly different results depending on the difference in the preference level for the presented food items, as well as clearly nonrandom waiting times, displaying forward-planning and economic evaluation of the situation at hand. As in most other species, results were markedly better when exchanging for quality as opposed to quantity. These results provide further evidence for temporal discounting in birds and fit in with the data gained on corvids and parrots in recent years. (PsycINFO Database Record

Function and flexibility of object exploration in kea and New Caledonian crows.

A range of non-human animals frequently manipulate and explore objects in their environment, which may enable them to learn about physical properties and potentially form more abstract concepts of properties such as weight and rigidity. Whether animals can apply the information learned during their exploration to solve novel problems, however, and whether they actually change their exploratory behaviour to seek functional information about objects have not been fully explored. We allowed kea (Nestor notabilis) and New Caledonian crows (Corvus moneduloides) to explore sets of novel objects both before and after encountering a task in which some of the objects could function as tools. Following this, subjects were given test trials in which they could choose among the objects they had explored to solve a tool-use task. Several individuals from both species performed above chance on these test trials, and only did so after exploring the objects, compared with a control experiment with no prior exploration phase. These results suggest that selection of functional tools may be guided by information acquired during exploration. Neither kea nor crows changed the duration or quality of their exploration after learning that the objects had a functional relevance, suggesting that birds do not adjust their behaviour to explicitly seek this information.

Feather mites of the genera Dubininia and Cacatualges (Acari: Xolalgidae) associated with parrots (Aves: Psittaciformes) of the Old World.

This paper gives a systematic revision of feather mites of the genera Dubininia Vassilev, 1958 and Cacatualges Dabert, Badek and Skoracki, 2007 (Xolalgidae: Ingrassiinae) associated with parrots (Aves: Psittaciformes) of the Old World. Five new species are described: Cacatualges probosciger sp. n. from Probosciger aterrimus (Gmelin) (Cacatuidae) from New Guinea, Dubininia charmosynae sp. n. from Charmosyna pulchella Gray GR (Psittaculidae) from New Guinea, D. micropsittae sp. n. from Micropsitta pusio pusio (Scaltter) (Psittaculidae) from New Guinea, D. nestori sp. n. from Nestor notabilis Gould (Strigopidae) from New Zealand, and D. pezopori sp. n. from Pezoporus wallicus (Kerr) (Psittaculidae) from Tasmania, Australia. Four previously described species of Dubininia are redescribed based on material from type hosts: D. curta (Trouessart, 1885) from Platycercus elegans (Gmelin) (Psittaculidae), D. lorina (Trouessart, 1885) from Lorius domicella (Linnaeus) (Psittaculidae), D. melopsittaci Atyeo and Gaud, 1987 from Melopsittacus undulatus (Shaw) (Psittaculidae), and D. psittacina (Trouessart, 1885) from Strigops harboptilus Gray GR (Strigopidae) from New Zealand. A new diagnosis for the genus Dubininia is provided. A key to all presently known Dubininia species is provided for the first time.

Contemporary effective population size and predicted maintenance of genetic diversity in the endangered kea (Nestor notabilis)

ABSTRACTPopulation size and the potential for maintenance of genetic diversity are critical information for the monitoring of species of conservation concern. However, direct estimates of population size are not always feasible, making indirect genetic approaches a valuable alternative. We estimated contemporary effective population size (Ne) in the endangered kea (Nestor notabilis) using three different methods. We then inferred the census size (NC) using published Ne/NC ratios and modelled the future maintenance of genetic diversity assuming a number of demographic parameters. Short-term Ne was small with a range-wide Ne < 250–700, while NC was within the range of the current estimate (c. 1000–5000). Forward simulations showed low probability of retaining 90% of rare alleles without immigration. However, the probability of maintaining genetic diversity was high with immigration, juvenile survival of ≥ 30%, and an initial sex ratio of c. 0.5–0.6. Despite the low Ne in kea, predator control and/or artificial immigration might be sufficient to maintain the present genetic diversity.

Semen Collection and Spermatozoa Characteristics in the Kea Parrot (Nestor notabilis).

We describe the seminal characteristics of the kea parrot (Nestor notabilis), an endangered species endemic to the South Island of New Zealand. Semen was collected in the full breeding season from 6 birds in the collection of an amateur aviculturist. The manual massage technique was used. A total of 25 ejaculates was collected and evaluated for volume, degree of contamination, and spermatozoa concentration; motility and kinetic parameters were assessed on diluted samples (modified Tyrode's Albumin Lactate Pyruvate, pH 8.2, temperature 37.5°C) with a computer-aided sperm analyzer. Four ejaculates were not analyzed because of an excessively high degree of contamination. Semen color ranged from transparent or turbid yellow to whitish. The geometric mean of spermatozoa number/ejaculate was 765.9 ± 2084.7 × 106. Total and progressive motility were 71.7% ± 20.0% and 59.8% ± 22.0%, respectively. Great variability was observed both among birds and among different ejaculates of the same subject. The seminal characteristics of kea are worth further investigation, with the aim of relating semen quality to fertility and defining a minimum inseminating dose for breeding purposes. A deeper knowledge of male reproductive biology also can increase the success of breeding programs and enable the use of the kea as a model species for other more threatened species, such as the kaka ( Nestor meridionalis ) and the kakapo (Strigops habroptila).

Kea show no evidence of inequity aversion.

It has been suggested that inequity aversion is a mechanism that evolved in humans to maximize the pay-offs from engaging in cooperative tasks and to foster long-term cooperative relationships between unrelated individuals. In support of this, evidence of inequity aversion in nonhuman animals has typically been found in species that, like humans, live in complex social groups and demonstrate cooperative behaviours. We examined inequity aversion in the kea (Nestor notabilis), which lives in social groups but does not appear to demonstrate wild cooperative behaviours, using a classic token exchange paradigm. We compared the number of successful exchanges and the number of abandoned trials in each condition and found no evidence of an aversion to inequitable outcomes when there was a difference between reward quality or working effort required between actor and partner. We also found no evidence of inequity aversion when the subject received no reward while their partner received a low-value reward.

Supplemental Material for Kea (Nestor notabilis) Decide Early When to Wait in Food Exchange Task

Supplemental Material for Kea (Nestor notabilis) Decide Early When to Wait in Food Exchange Task

Audiogram of the kea parrot, Nestor notabilis.

Vocal communication requires the sender to produce a sound, which transmits through the environment and is perceived by the receiver. Perception is dependent on the quality of the received signal and the receiver's frequency and amplitude sensitivity; hearing sensitivity of animals can be tested using behavioural detection tasks, showing the physical limitations of sound perception. Kea parrots (Nestor notabilis) were tested for their ability to hear sounds that varied in terms of both frequency and amplitude by means of a simple auditory detection task. Audiograms for three kea were similar, with the region of highest sensitivity (1-5 kHz) corresponding to the frequency of the highest amplitude in kea calls. Compared with other parrots and other bird taxa, the overall shape of the kea audiogram follows a similar pattern. However, two potentially interesting differences to the audiograms of other birds were found: an increase in sensitivity at approximately 12 kHz and a decreased sensitivity to frequencies below 1 kHz.

Kea: A New Tool to Obtain Stellar Parameters from Low to Moderate Signal-to-noise and High-resolution Echelle Spectra**Named after Nestor notabilis an alpine parrot native to New Zealand.

In this paper, we describe Kea a new spectroscopic fitting method to derive stellar parameters from moderate to low signal-to-noise, high-resolution spectra. We developed this new tool to analyze the massive data set of the Kepler mission reconnaissance spectra that we have obtained at McDonald Observatory. We use Kea to determine effective temperatures (Teff), metallicity ([Fe/H]), surface gravity (log g), and projected rotational velocity (). Kea compares the observations to a large library of synthetic spectra that covers a wide range of different Teff, [Fe/H], and log g values. We calibrated Kea on observations of well-characterized standard stars (the Kepler field “platinum” sample) that range in Teff from 5000 to 6500 K, in [Fe/H] from −0.5 to +0.4 dex, and in log g from 3.2 to 4.6 dex. We then compared the Kea results from reconnaissance spectra of 45 Kepler objects of interest (KOIs) to stellar parameters derived from higher signal-to-noise spectra obtained with Keck/HIRES. We find typical uncertainties of 100 K in Teff, 0.12 dex in [Fe/H], and 0.18 dex in log g.