Gouldian Finch Research Articles

Watch out! High vigilance at small waterholes when alone in open trees.

An animal's environment contains many risks causing animals to scan their environment for potential predators and threats from conspecifics. How much time they invest in such vigilance depends on environmental and social factors. Most vigilance studies have been conducted in a foraging context with little known about vigilance in other contexts. Here we investigated vigilance of Gouldian finches at waterholes considering environmental and social factors. Gouldian finches are colour polymorphic with two main head colours in both sexes co-occurring in the same population, black-headed and red-headed. Data collection was done on birds sitting in trees surrounding waterholes by measuring the frequency of head movements, which reflects how frequently they change their field of view, i.e., scan different areas in their environment. A higher frequency generally reflects higher vigilance. Gouldian finches had a higher frequency of head movements when at small waterholes and when sitting in open, leafless trees. Moreover, head movements were higher when birds were alone in the tree as compared to groups of birds. Finally, birds in same head colour morph groups had a higher frequency of head movements than birds in mixed head colour groups. Results indicate heightened vigilance with increased perception of predation risk (small waterholes, open exposed perch, when alone) but that social vigilance also played a role (group composition) with particularly the aggressive red-headed birds being more vigilant when together with other red-headed birds. Future research should investigate the effect of smaller waterholes as global warming will cause smaller waterholes to become more common for longer periods of time, which can increase stress in the birds.

A RETROSPECTIVE EVALUATION OF MORBIDITY AND MORTALITY IN ASSOCIATION WITH INFESTATION BY THE MITE STERNOSTOMA TRACHEACOLUM IN AN AVIARY-HOUSED POPULATION OF GOULDIAN FINCHES (CHLOEBIA GOULDIAE).

The Rhynonyssid mesostigmatic mite, Sternostoma tracheacolum, is a well-documented endoparasitic hematophagous arthropod of the respiratory tracts of multiple avian species, particularly Estrildid finches and canaries. In this retrospective study, 175 medical and 278 pathology records for the Gouldian finch (Chloebia gouldiae) population (N = 377) at the San Diego Zoo between 2013 and 2021 were analyzed to evaluate the effectiveness of ivermectin-based prophylaxis. A multivariable negative binomial regression model was constructed to evaluate the population effects of monthly treatments on morbidity or mortality associated with respiratory mites. While controlling for other factors in the model, the prophylactic treatment did not significantly reduce the monthly rate of mite-associated morbidity or mortality (IRR = 1.017, 95% CI: 0.997-1.036, P = 0.0759); however, low proportions of the population were prophylactically treated over time. Different factors were significant when separately evaluating adjusted associations with respiratory morbidity and mortality. The findings suggest increased rates of respiratory morbidity for each successive year of the study period (IRR = 1.180, 95% CI: 1.046-1.342, P = 0.0090) and increased rates of mite-associated mortality occurring annually between May and October (IRR = 1.697, 95% CI: 1.034-2.855, P = 0.0404) compared to the wet winter season. Our findings highlight the need to continually evaluate and optimize treatment regimens in zoological collections. Further investigations into this host-parasite relationship and potential treatments and preventive therapies are warranted.

Salience Beats Individual Cue Preferences

Animals can use different cues to memorise food resources, which can be broadly divided into spatial and feature cues. Differences in species-specific preferences for spatial or feature cues has been historically linked to their reliance on spatial information (food-caching and migratory species prefer spatial cues), but more recently, attention has shifted to procedural differences largely affecting the salience of cues. Here, we investigated cue preferences in the colour-polymorphic Gouldian Finch to test a range of hypotheses. Birds were trained to find food either in a white or coloured feeder always positioned in the same location. In experimental trials, feeders were swapped, dissociating the feature and the spatial cue from the feature cue rewarded. Similar numbers of birds preferred the feature or the spatial cue in the first experimental trial. Preferences were not affected by head colour morph, sex or age group. However, birds with a spatial preference changed their choices over time, resulting in a significant number of birds choosing the feature cue at the end of the experiment. These results indicate that Gouldian Finches have individual preferences for one cue type or the other but can change their preference flexibly depending on the salience of the cue.

Entopallium Lost GFAP Immunoreactivity during Avian Evolution: Is GFAP a “Condition Sine Qua Non”?

Introduction: The present study demonstrates that in the same brain area the astroglia can express GFAP (the main cytoskeletal protein of astroglia) in some species but not in the others of the same vertebrate class. It contrasts the former opinions that the distribution of GFAP found in a species is characteristic of the entire class. The present study investigated birds in different phylogenetic positions: duck (Cairina moschata domestica), chicken (Gallus gallus domesticus), and quails (Coturnix japonica and Excalfactoria chinensis) of Galloanserae; pigeon (Columba livia domestica) of a group of Neoaves, in comparison with representatives of other Neoaves lineages, which emerged more recently in evolution: finches (Taeniopygia guttata and Erythrura gouldiae), magpie (Pica pica), and parrots (Melopsittacus undulatus and Nymphicus hollandicus). Methods: Following a perfusion with 4% buffered paraformaldehyde, immunoperoxidase reactions were performed with two types of anti-GFAP: monoclonal and polyclonal, on floating sections. Results: The entopallium (formerly “ectostriatum,” a telencephalic area in birds) was GFAP-immunopositive in pigeon and in the representatives of Galloanserae but not in songbirds and parrots, which emerged more recently in evolution. The lack of GFAP expression of a brain area, however, does not mean the lack of astroglia. Lesions induced GFAP expression in the territory of GFAP-immunonegative entopallia. It proved that the GFAP immunonegativity is not due to the lack of capability, but rather the suppression of GFAP production of the astrocytes in this territory. In the other areas investigated besides the entopallium (optic tectum and cerebellum), no considerable interspecific differences of GFAP immunopositivity were found. It proved that the immunonegativity of entopallium is due to neither the general lack of GFAP expression nor the incapability of our reagents to detect GFAP in these species. Conclusion: The data are congruent with our proposal that a lack of GFAP expression has evolved in different brain areas in vertebrate evolution, typically in lineages that emerged more recently. Comparative studies on GFAP-immunopositive and GFAP-immunonegative entopallia may promote understanding the role of GFAP in neural networks.

A complete species-level phylogeny of the Erythrura parrotfinches (Aves: Estrildidae)

Identifying species boundaries and phylogenetic relationships among groups of closely related species provides a necessary framework for understanding how biodiversity evolves in natural systems. Here we present a complete phylogeny of the avian genus Erythrura (family Estrildidae) commonly known as parrotfinches, which includes species threatened by habitat loss and the pet trade. Using both mitogenome and reduced-representation genome-wide nuclear DNA sequence data, we reconstructed the evolutionary history of the group by sampling all 12 recognized species, four of which had not previously been studied in a phylogenetic context. We included intra-species geographic sampling that allowed us to comment on species limits in some taxa. We recovered the Gouldian Finch (Chloebia gouldiae) of Australia which has often been placed in the monotypic genus Chloebia, as being sister to a clade comprising all Erythrura species. In addition, we recovered a well-supported clade comprising eight species distributed throughout the Pacific Island eco-region, whereas those species occurring in continental southeast Asia, the Greater Sundas, and the Philippines, were recovered as earlier branching lineages. Of note was the early branching of the Fiji-endemic E. kleinschmidti which corroborates its unique phenotype. We also found a deep phylogenetic split (8.59% corrected, 7.89% uncorrected divergence in the mitochondrial gene ND2) between the Java and Philippine populations of E. hyperythra, indicating unrecognized species-level diversity within this taxon. In contrast, genome-wide nuclear data suggested that the New Guinea endemic species E. papuana is embedded within the widespread species E. trichroa in all phylogenetic reconstructions, corroborating previously published mitochondrial data that suggested a similar pattern. By generating a phylogenetic hypothesis for the relationships among all species of Erythrura parrotfinches, we provide a framework for better understanding the extant diversity and evolutionary history of this group.

Enclosure Background Preferences Differ between Sexes and Color Morphs in the Gouldian Finch.

Most wild animals camouflage well into their environment, providing protection from predators, whereas captive animals often contrast with their background. This can cause stress for the animal, which may perceive it as being exposed. Theory suggests that prey is more difficult to detect in front of complex backgrounds; hence, animals should prefer complex over simple backgrounds. We tested this in the polymorphic Gouldian finch by providing a complex background pattern in one half of the flight cage and a simple background pattern in the other half for 10 days (phase 1). Patterns were then swapped and presented for another week (phase 2). Groups of four birds consisting of either pure black-headed or red-headed or mixed head color (two black-headed and two red-headed) pairings were tested. Gouldian finches spent significantly more time in front of the simple background in phase 1 but not in phase 2. Specifically, females preferred the simple background in phase 1 significantly more than males. Moreover, red-headed birds consistently perched in front of the simple background, whereas black-headed birds used both backgrounds, particularly in phase 2. Results indicate that background preferences differ between sexes and morphs, which should be considered when designing backgrounds. Moreover, natural habitat preferences need consideration.

The threatened Gouldian finch preferentially forages in prescribed burnt savannas

Background The granivorous finches of Australia’s tropical savannas heavily rely on a sequence of perennial and annual grass seed production to feed throughout the year. An increase in late dry season wildfires has been suggested to detrimentally effect seed production sequence and has been attributed to poor physiological condition and a reduction in fitness of granivorous finches. Early dry season prescribed burning is an asset protection management strategy often implemented to reduce the incidence of late dry season wildfire, but has also been shown to improve the abundance and nutritional quality of grass seed Aims To assess whether the Gouldian finch (Chloebia gouldiae) preferentially used areas that were subject to early dry season prescribed burning over areas that were not burnt. Methods The creation of a landscape mosaic across the landscape with varying fire histories. Then the assessment of individual finch movement and site utilisation using VHF-radio telemetry transmitters, detected by an array of static receivers deployed across the landscape. Key results Finches significantly preferred to forage in areas burnt in the early season every 2–3 years. Conclusions The study demonstrates that early dry season prescribed burning creates preferred foraging habitat patches for Gouldian finches within savanna fire mosaics.

When to Return to Normal? Temporal Dynamics of Vigilance in Four Situations

Vigilance is an important behaviour to monitor the environment from detecting predators to tracking conspecifics. However, little is known about how vigilance changes over time either without disturbance (vigilance decrement) or after a change occurred. The time course of vigilance can indicate how animals perceive a situation and the potential mechanism used to deal with it. I investigated the time course of vigilance in Gouldian Finches in four situations (familiar environment, two changed environments–novel object at a neutral location (exploration trial) or above the feeder (neophobia trial), novel environment). The frequency of head movements was assessed in four consecutive 15-min blocks in same sex pairs with a high frequency generally seen as indicative of high vigilance. Vigilance decreased over time in the familiar situation indicating vigilance decrement with a similar time course in the exploration trial. Vigilance was consistently high in the neophobia trial and only returned to normal in the last block. Finally, vigilance plummeted in the novel environment and did not return to normal within an hour. Results suggest that perceived threats affected vigilance and that information gathering reduced uncertainty allowing vigilance to return to normal levels but with different time courses depending on the situation.

Is vigilance a personality trait? Plasticity is key alongside some contextual consistency.

Animals regularly scan their environment for predators and to monitor conspecifics. However, individuals in a group seem to differ in their vigilance linked to age, sex or state with recent links made to personality. The aims of the study were to investigate whether a) individuals differ consistently in their vigilance, b) vigilance is linked to other personality traits and c) other factors affect vigilance in the colour polymorphic Gouldian finch. Birds were tested in same (red-headed or black-headed) or mixed head colour morph same sex pairs in four contexts (novel environment, familiar environment, two changed environments). Vigilance was measured as horizontal head movements. Vigilance showed contextual consistency but no long-term temporal consistency over a year. Head movements were only weakly linked to other personality traits indicative of a risk-reward trade-off with more explorative individuals being less vigilant. Vigilance was highly plastic across situations and affected by group composition. Mixed head colour morph pairs made more head movements, potentially linked to higher social vigilance. Results indicate that vigilance is a highly plastic trait affected by personality rather than a personality trait on its own, which allows adapting vigilance to different situations.

Selected Effects and Comparative Propensities

ABSTRACT Several other commentators capably articulate and defend an important objection to Christie, Brusse, et al.: the claim that the existence of a trait is entirely, rather than partially explained by the effects for which it was selected is stronger than the selected effects theorist needs or seeks to defend. Nonetheless, Christie, Brusse, et al.’s cases do draw our attention to a point about the explanatory relation between selected effects functions and their bearers that has not been emphasized by selected effects theorists, although some have quietly accommodated it. This is the idea that, for a trait T to be for performing F, T’s ability to perform F must figure in an explanation of T’s existence in a particular way. It is not T’s absolute propensity to produce F as an effect but its comparative propensity, as compared with alternatives to T, that must figure in the explanation. The pattern of explanation sought by selected effects theorists to underwrite function attributions therefore requires a correct choice of comparison class. When we spell this idea out, we arrive at a hypothesis about what is bothering Christie, Brusse, et al. about the cases they find problematic. Consider their Gouldian finches. Focusing on the role of comparative propensities, the difficulty becomes clear: the claim that the red-heads’ hormonal levels have persisted in the finch population because they have had the effect of dislodging competitors more reliably than the black-heads’ hormonal levels is incorrect. The red-head phenotype doesn’t stick around by outdoing the black-heads at dislodging, since the black-heads can’t be outdone at something they are not in the business of doing in the first place. However, this point is not in the end a serious problem for selected effects theories because the problem comes from a wrong choice of comparison class: namely, black-heads, rather than inferior red-heads. If the hormonal trait of today’s red-heads reached or persists at its present frequency because of some historical selection against other, perhaps quite similar, hawkish variants, this trait will be for dislodging competitors, since it is around because it outdid those alternatives at dislodging.

Pathogenicity of Avian Polyomaviruses and Prospect of Vaccine Development.

Polyomaviruses are nonenveloped icosahedral viruses with a double-stranded circular DNA containing approximately 5000 bp and 5–6 open reading frames. In contrast to mammalian polyomaviruses (MPVs), avian polyomaviruses (APVs) exhibit high lethality and multipathogenicity, causing severe infections in birds without oncogenicity. APVs are classified into 10 major species: Adélie penguin polyomavirus, budgerigar fledgling disease virus, butcherbird polyomavirus, canary polyomavirus, cormorant polyomavirus, crow polyomavirus, Erythrura gouldiae polyomavirus, finch polyomavirus, goose hemorrhagic polyomavirus, and Hungarian finch polyomavirus under the genus Gammapolyomavirus. This paper briefly reviews the genomic structure and pathogenicity of the 10 species of APV and some of their differences in terms of virulence from MPVs. Each gene’s genomic size, number of amino acid residues encoding each gene, and key biologic functions are discussed. The rationale for APV classification from the Polyomavirdae family and phylogenetic analyses among the 10 APVs are also discussed. The clinical symptoms in birds caused by APV infection are summarized. Finally, the strategies for developing an effective vaccine containing essential epitopes for preventing virus infection in birds are discussed. We hope that more effective and safe vaccines with diverse protection will be developed in the future to solve or alleviate the problems of viral infection.

Embryonal Tumour in the Eye of a Lady Gouldian Finch (Erythrura gouldiae) and Limited Review of Intraocular Tumours in Birds

Primary intraocular tumours are infrequent in birds. A 2-year-old male Lady Gouldian finch (Erythrura gouldiae) originally presented to the referring veterinarian after the owner noticed mild swelling of the right eye. After the eye had enlarged rapidly and bulged from the orbit, the bird was seen at the referral hospital. Enucleation was attempted but the bird died after sedation. The eye was removed and, on sectioning, a mass was seen primarily in the vitreous chamber with extension through the sclera to the retrobulbar area. After routine histology, immunohistochemistry and electron microscopy, the mass was diagnosed as an embryonal tumour of probable retinal origin. This type of tumour has rarely been documented in birds and we could find no references to any report in Estrildidae.

Sympatric finches increase trophic and spatiotemporal partitioning to enable coexistence through periods of low resource availability

Abstract Ecological niche theory dictates that sympatric species cannot occupy the same ecological niche at the same time. Sympatric granivorous finch species in tropical savannas appear to contradict this theory by moving in mixed‐species flocks and feeding together upon the same resources. Here, we explored this contradiction by tracking individuals from three finch species (Gouldian—Chloebia gouldiae, long‐tailed—Poephila acuticauda and masked finch—P. personata) often seen feeding together, while simultaneously determining the dietary composition during periods of high and low resource abundance. Dietary composition was characterised using stable isotope ratios of δ13C and δ15N within the blood, and foraging areas were determined from continuous detection using passive VHF radio telemetry. Individuals were sampled early in the dry season when grass seeds were abundant, in the middle of the dry season and at the end when seeds were very scarce. The results showed plasticity in ecological niche overlap among the three finch species depending on grass seed availability within the landscape. In the early dry season, the species foraged together on the abundant grass seed. As the dry season progressed and grass seed availability declined, masked and long‐tailed finches exhibited greater spatial partitioning, masked and Gouldian finches increased dietary partitioning, and long‐tailed and Gouldian finches increased both dietary and spatial partitioning. Our study showed that sympatric granivorous finches utilise trophic and spatiotemporal partitioning to enable coexistence through periods of low resource availability in tropical savannas. Gouldian finches increased activity and ranging behaviour, while long‐tailed and masked finches diversified their diet. Read the free Plain Language Summary for this article on the Journal blog.

Germline-Restricted Chromosomes and Autosomal Variants Revealed by Pachytene Karyotyping of 17 Avian Species

Karyotypes of less than 10% of bird species are known. Using immunolocalization of the synaptonemal complex, the core structure of meiotic chromosomes at the pachytene stage, and centromere proteins, we describe male pachytene karyotypes of 17 species of birds. This method enables higher resolution than the conventional analyses of metaphase chromosomes. We provide the first descriptions of the karyotypes of 3 species (rook, Blyth’s reed warbler, and European pied flycatcher), correct the published data on the karyotypes of 10 species, and confirm them for 4 species. All passerine species examined have highly conservative karyotypes, 2n = 80–82 with 7 pairs of macrochromosomes (including the ZZ sex chromosome pair which was not unambiguously distinguished from other macrochromosomes in most species) and 33–34 pairs of microchromosomes. In all of them, but not in the common cuckoo, we revealed single copies of the germline-restricted chromosomes varying in size and morphology even between closely related species. This indicates a fast evolution of this additional chromosome. The interspecies differences concern the sizes of the macrochromosomes, morphology of the microchromosomes, and sizes of the centromeres. The pachytene cells of the gouldian finch, brambling, and common linnet contain heteromorphic synaptonemal complexes indicating heterozygosity for inversions or centromere shifts. The European pied flycatcher, gouldian finch, and domestic canary have extended centromeres in several macro- and microchromosomes.

Juvenile Gouldian finches (Erythrura gouldiae) form sibling subgroups during social integration.

The formation of social relationships in complex groups is critical in shaping patterns of social organization and behavioral development. In many birds, young individuals remain dependent on their parents for extended periods but must abruptly transition to navigating interactions in the wider group after independence. While lack of social relationships during this period is detrimental in the development of later social skills, little is known about the social relationships juveniles form after independence in many bird species. In this study, we describe patterns of social interactions in juvenile Gouldian finches (Erythrura gouldiae) during transitions from family groups into flocks of unfamiliar individuals. Twenty juveniles from four families were introduced into two flocks. After introductions, juveniles showed a gradient of approach rates with most approaches directed toward siblings, followed by juvenile peers, adult females, and lastly adult males. Significant preferences for siblings resulted in the emergence of sibling subgroups within the larger social network. This intentional self-assortment of siblings suggests that sibling subgroups are an important bridge linking social connections within the family and the wider group. Such findings suggests that sibling relationships have a critical role in the socialization after independence, as well as structuring the social organization of Gouldian finch flocks.

Morph Composition Matters in the Gouldian Finch (Chloebia gouldiae): Involvement of Red-Headed Birds Increases Vigilance

Animals invest in costly vigilance to detect threats. Joining groups reduces these costs, which can be further reduced in mixed-species assemblages. In colour-polymorphic species, morphs often experience different predation pressure and vary in a variety of traits. However, little is known about differences in vigilance or how group composition affects vigilance. The aim was to investigate whether higher conspicuousness increased vigilance and whether vigilance was reduced in mixed-morph groups like in mixed-species assemblages. I tested vigilance in the colour-polymorphic Gouldian Finch (Chloebia gouldiae). Same sex pairs of different age and of either pure (red-red or black-black) or mixed head colour were exposed to three contexts (familiar, changed and novel environment) and head movements were recorded. All birds reduced the frequency of head movements with increasing novelty, indicating different vigilance strategies (switching from a searching to a tracking strategy) depending on the situation. While vigilance did not differ between morphs, morph composition mattered. Black-headed pairs made fewer head movements than mixed-head colour pairs. Results indicated that conspicuousness did not affect vigilance, possibly due to existing adaptations to reduce predation risk. However, whenever red-headed birds were involved, vigilance increased either because of higher group conspicuousness or prevalence of aggression.

Individual Variation in Dietary Wariness Is Predicted by Head Color in a Specialist Feeder, the Gouldian Finch

Shifts in resource availability due to environmental change are increasingly confronting animals with unfamiliar food types. Species that can rapidly accept new food types may be better adapted to ecological change. Intuitively, dietary generalists are expected to accept new food types when resources change, while dietary specialists would be more averse to adopting novel food. However, most studies investigating changes in dietary breadth focus on generalist species and do not delve into potential individual predictors of dietary wariness and the social factors modulating these responses. We investigated dietary wariness in the Gouldian finch, a dietary specialist, that is expected to avoid novel food. This species occurs in two main head colors (red, black), which signal personality in other contexts. We measured their initial neophobic responses (approach attempts before first feed and latency to first feed) and willingness to incorporate novel food into their diet (frequency of feeding on novel food after first feed). Birds were tested in same-sex pairs in same and different head color pairings balanced across experiments 1 and 2. Familiar and novel food (familiar food dyed) were presented simultaneously across 5 days for 3 h, each. Gouldian finches fed on the familiar food first demonstrating food neophobia, and these latencies were repeatable. Birds made more approach attempts before feeding on novel than familiar food, particularly red-headed birds in experiment 1 and when partnered with a black-headed bird. Individuals consistently differed in their rate of incorporation of novel food, with clear differences between head colors; red-headed birds increased their feeding visits to novel food across experimentation equaling their familiar food intake by day five, while black-headed birds continually favored familiar food. Results suggest consistent among individual differences in response to novel food with red-headed birds being adventurous consumers and black-headed birds dietary conservatives. The differences in food acceptance aligned with responses to novel environments on the individual level (found in an earlier study) providing individuals with an adaptive combination of novelty responses across contexts in line with potential differences in movement patterns. Taken together, these novelty responses could aid in population persistence when faced with environmental changes.

Sex and morph differences in age-dependent trait changes in a polymorphic songbird.

There is growing evidence of important variation in how animals age, in particular in how the expression of traits changes with age among different species and populations. However, less is known about variation within populations, which may include variation in ageing patterns between different types of individuals (e.g. sexes or distinct polymorphisms) and between different types of traits (e.g. general traits versus those used in social signalling contexts). We used 6years of longitudinal data to examine age-related changes in trait expression in a captive population of Gouldian finches (Erythrura gouldiae), a socially monogamous songbird with genetically determined colour morphs that differ in behaviour and physiology. We contrasted ageing patterns of different types of traits (social signalling vs. size-related) in both sexes and in two colour morphs, using a mixed model approach to account for both within- and between-individual effects. We found pronounced sex differences in how social signalling traits change with age, showing a quadratic pattern in males, but not changing with age in females. In contrast, we observed no sex-specific ageing patterns in size traits. We also found subtle morph differences in how size-related traits changed with age, with black morphs stable or increasing with age while red morphs showing a decline with age. Finally, we found an interesting sex by morph interaction in one important social signal (headband width). These results highlight the importance of using within-individual approaches to understand ageing patterns across types of individuals (sex, morph, etc.) and the need for further research on the ageing patterns of traits that may experience different selective pressures.

MOMDPs: A Solution for Modelling Adaptive Management Problems

In conservation biology and natural resource management, adaptive management is an iterative process of improving management by reducing uncertainty via monitoring. Adaptive management is the principal tool for conserving endangered species under global change, yet adaptive management problems suffer from a poor suite of solution methods. The common approach used to solve an adaptive management problem is to assume the system state is known and the system dynamics can be one of a set of pre-defined models. The solution method used is unsatisfactory, employing value iteration on a discretized belief MDP which restricts the study to very small problems. We show how to overcome this limitation by modelling an adaptive management problem as a restricted Mixed Observability MDP called hidden model MDP (hmMDP). We demonstrate how to simplify the value function, the backup operator and the belief update computation. We show that, although a simplified case of POMDPs, hm-MDPs are PSPACE-complete in the finite-horizon case. We illustrate the use of this model to manage a population of the threatened Gouldian finch, a bird species endemic to Northern Australia. Our simple modelling approach is an important step towards efficient algorithms for solving adaptive management problems.

Birds of different morphs use slightly different strategies to achieve similar reproductive performance following heatwave exposure.

Responses to extreme climatic events may differ between individuals of distinct morphs which differ in life-history strategies, resulting in climate change 'winners' and 'losers' within species. We examined the reproductive performance and carry-over effects on offspring of black- and red-headed Gouldian finches Erythrura gouldiae after exposure to simulated heatwaves of moderate or severe intensity. We expected black-headed pairs' reproductive performance to decline after the severe heatwave because only the condition of black-headed females deteriorates during such a heatwave. Supporting the fact that Gouldian finches of different morphs use alternative reproductive strategies, we found that black-headed females initiated egg-laying a month earlier than red-headed females after experiencing a severe heatwave. We also found that this severe heatwave resulted in shorter spermatozoa in males irrespective of their morph. Despite these effects associated with heatwave intensity, the overall reproductive performance of both morphs was not affected by this factor, which was possibly due to an increased nestling provisioning rate by parents after exposure to the severe heatwave. However, offspring still bore the cost of parental exposure to the severe heatwave, as they showed a reduced condition (lower plasma antioxidant capacity and transient lower breathing rate) and higher oxidative damage (at least in fledglings with black-headed parents). These results suggest that inter-morph phenotypic variability in the Gouldian finch does not result in clear differences in reproductive performance following heatwave exposure, despite basal phenotypic differences between morphs. Whether animals using alternative reproductive strategies are, in the end, differently affected by climate changes will likely depend on the capacity of their offspring to recover from altered developmental conditions.